Precursor To An Outburst?

Dwarf novae are compact binaries where one star is a sun-like star and the other member is a white dwarf, orbiting so close that it is literally stripping the outer atmosphere off its partner. The material streams over to the white dwarf but can�t slam down to the surface. Instead, it goes into orbit around the white dwarf, forming what is known as an accretion disk.

Image used with permission. Copyright Mark A. Garlick. Do not use this image without permission.

Eventually, the accretion disk builds up enough material to become unstable. The disk material falls down onto the surface of the white dwarf, causing a thermonuclear explosion that releases all kinds of energy across the electromagnetic spectrum. Optically, we see these as sudden brightenings of several magnitudes in a matter of hours. These outbursts can last from days to weeks. The system eventually simmers down into quiescence and the whole process starts over again.

The majority of these binaries have periods measured in hours. Think about that for a second. Imagine a white dwarf racing around our sun in a few hours, so close it is stripping material from the surface. Everything about these systems is extreme.

Some dwarf novae, like SS Cygni, go into outburst every couple weeks. Some may take years or decades to build up enough steam to explode into outburst. No one knows when the next outburst will occur, making these a favorite target for amateur astronomers to monitor on a nightly basis.

Occasionally, one of these cataclysmic variables will tip its hand to an upcoming outburst, by becoming active a week or more before the big event. Sometimes they will actually have a minor precursor outburst, fade to quiescence and then go into a major outburst.

Over the last couple nights, several UK observers have reported an increase in the quiescent level of V630 Cas. It has been measured peeking its head into the 15th magnitude range, slightly brighter than its normal quiescent magnitude around 16.5V.
V630 Cas is rare example of a dwarf nova with a long orbital period. Its period is measured in days, not hours.

The last recorded outburst of V630 Cas was in 1992, and lasted about three months from beginning to end. That is a long time for an outburst to last! The only other recorded outburst was in 1950. Obviously, outbursts of this system are very rare, so astronomers will be excited to catch every last detail from beginning to end of the next outburst.

This current 'activity' could be the precursor to an upcoming outburst. Observers will be paying close attention to V630 Cas in the coming weeks to make sure that a rare, and possibly long, outburst isn't missed.

I�ll let you know what happens.

Big Eyes on a Big Star

Mass is constantly being recycled in the universe. One of the most common ways recycling is achieved is through stellar mass-loss. All stars exhibit some form of mass loss. Smaller stars can be quite stingy and hold onto their mass by burning away slowly. Other massive stars can lose prodigious amounts of mass each year. The rate at which a star loses mass depends on its initial mass, age, spectral type, luminosity class, rotation rate, evolutionary stage, even the proximity of a companion star.

The first generation of stars consisted mostly of hydrogen and helium. These stars then seeded the interstellar medium with heavier elements, shedding material via massive winds, planetary nebulae and supernova explosions.

This material then became the building blocks for the next generation of stars and planets. Understanding mass loss is essential for following the evolution of single stars, binaries, star clusters, and galaxies.

However, mass loss is among our weakest areas in understanding fundamental stellar processes. In large part, this is due to lack of detailed, direct observations of stellar photospheres and the mass-loss process. High-resolution optical interferometry with telescope arrays is beginning to provide these data, ushering in a promising a new era in mass-loss studies.

The angular resolution that a telescope can achieve is proportional to its diameter. The larger the telescope, the better its resolution. The purpose of astronomical interferometry is to mix signals from a collection of telescopes to produce images having the same angular resolution as an instrument the size of the entire collection.

The Very Large Telescope Array (VLT)

Recently, a team of French astronomers captured one of the sharpest color images ever made. The team members are Jean-Baptiste Le Bouquin and Antoine M�rand (ESO), Sylvestre Lacour and St�phanie Renard (LAOG, CNRS, Grenoble, France), and Eric Thi�baut (AIRI, Observatoire de Lyon, France).

The image was taken over several consecutive nights with ESO's Very Large Telescope Interferometer (VLTI), a virtual telescope about 100 meters across. The result is an amazing image that reveals a spherical molecular shell around an evolved Mira star, T Leporis, 500 light-years away!

Image showing T Leporis' atmospheric layers and the size of the star relative to the diameter of the Earth's orbit.
(Credit: ESO)

Miras are giant pulsating variable stars. Evolved stars like this have used up most of their nuclear fuel, causing them to swell up to enormous radii and become unstable. This internal instability causes them to expand and contract more or less regularly. T Lep pulsates with a period of 380 days, and in the process loses the equivalent of the Earth�s mass every year to space. In the end, all that is left is a white dwarf, the ash of the core, surrounded by the gases lost to space from the star�s wind and tenuous grip on its outer layers. We see these stellar remnants as planetary nebula elsewhere in the galaxy. Our Sun will become a Mira in a few billion years, engulfing the inner planets in its final blaze of glory.

Mira stars are among the biggest factories of molecules and dust in the Universe. Since the molecules and dust are formed in the outer layers of a Mira's atmosphere, astronomers would like to be able to see these layers to better understand the processes of mass loss and dust formation. Until now, this has been all but impossible due to the distance to even the nearest stars. The angular size of even giant swollen stars like T Lep were too small to image from Earth.

�T Leporis looks so small from the Earth that only an interferometric facility, such as the VLTI at Paranal, can take an image of it. VLTI can resolve stars 15 times smaller than those resolved by the Hubble Space Telescope,� says Le Bouquin.

�We were able to construct an amazing image, and reveal the onion-like structure of the atmosphere of a giant star at a late stage of its life for the first time,� says team member, Antoine M�rand. �Numerical models and indirect data have allowed us to imagine the appearance of the star before, but it is quite astounding that we can now see it, and in color.

Obtaining images like these was one of the main motivations for building the Very Large Telescope Interferometer. We have now truly entered the era of stellar imaging.�

400 years after Galileo turned his tiny telescope towards the sky, we can now actually see stars atmospheres directly, using some of astronomy's most amazing new tools of discovery.

SimoCowboy Ready to Roll!

Next week is a conference I have been excited about attending for a long time. It's an entire week devoted to my specialty, cataclysmic variables. The list of attendees is a literal who's who of CV research.

The conference is called Wild Stars in the Old West II. This special get together doesn't come around that often. I wouldn't miss it for the world.


From the website:

"It has been ten years since the last North American Workshop on Cataclysmic Variables and nearly five years since the last international meeting on cataclysmic variables and their kin. Of particular interest since these last meetings are new results based on observational platforms such as GALEX, Spitzer, Chandra, XMM INTEGRAL and Swift/BAT, large surveys such as SDSS and planned Pan-STARRS and LSST, smaller but equally important surveys such as All Sky Automated Survey (ASAS), Catalina Sky Survey, �Pi of the Sky�, ROTSE, results from large aperture ground-based telescopes, theoretical advances, and evolutionary relationships of CVs to other binary stars."

I plan to blog about the proceedings and talks, and I'm taking a digital audio recorder to do some one on one interviews with some of the leaders in CV research. These will be turned into podcasts for Slacker Astronomy and Restless Universe.

Sunday is a travel day, and the welcome get together in Tucson. Monday, the real stuff begins. Check back for updates next week.

Yeehaw!

Wild Stars Day Two

You better show up wide awake for these conferences. Tuesday morning we jumped in feet first into the crazy world of AM CVn type stars. This is a rare class of stars that has been garnering more attention lately due to their extremely short orbital periods, (we're talking 10-60 minutes here), and the fact they are sources for low frequency gravitational waves.

AM CVn spectra are totally devoid of Hydrogen lines. They show a rich Helium spectrum along with processed heavy element lines. This makes them exciting to astronomers because supernovae spectra don't show hydrogen, so these stars may be supernovae progenitors. If you want to get grant support or telescope time these days, it helps if you're proposal has something to do with the sexy topics of exoplanets, supernovae or dark matter.

There are several proposed channels for the evolution of these stars. By the third paper of the morning we had heard about all the possible ways these stars can be born and how they may die as helium Ia supernovae. AM CVn's are thought to form via 2-3 different "channels".

1-A detached white dwarf (DWD) system, formed through a series of Common Envelope evolutions, shrinks as a result of angular momentum losses due to Gravitational wave Radiation (GWR). Eventually, the less massive star fills its Roche radius and mass transfer commences. The system then evolves to higher periods due to redistribution of angular momentum.

...or, 2- a low mass helium donor transfers mass to a white dwarf accretor. The system passes through a minimum in period of ~ 10 minutes. The period increases after this minimum and mass transfer keeps falling. During this process the helium donor goes from being a non-degenerate to a degenerate star.

...or , 3- they may evolve from cataclysmic variables with evolved donors. After significant mass loss, the exposed Helium core of the donor in a CV evolves similar to #2 Helium star track.

What's truly amazing, and mind bending if you haven't had enough coffee, is the fact that we just can't find helium core white dwarfs right now. Since these may be members of binary progenitors for both supernovae and classical novae, astronomers are forced to model how these stars contribute to colossal cosmic explosions using math, physics and imagination. Then they have to figure out a way to explain it to other astronomers and survive the question and answer session after they present their talk.

Kudos to graduate student Ken Shen for his paper on Unstable Helium Shell Burning on Accreting White Dwarfs. This young man knows his stuff and can give a presentation. I predict good things for his future.

After lunch we started hearing talks closer to my areas of interest. I already mentioned the awesome 3D Gas Dynamic Modeling movies shown in the talk given by D.V. Bisikalo. Then Don Hoard talked about Dusty Toads, a topic we have seen here before a few times.

SW Sex stars is another class of stars I wanted to learn more about. It seems that all eclipsing nova-like stars in the 3-4 hour period range are SW Sex stars. But eclipses are simply a line of sight effect, so they can't be considered a pre-requisite for inclusion in the SW Sex club. So Linda Schmidtobreick and her colleagues looked at a large sample of non-eclipsing stars in the 3-4 hour period range to see if they had the rest of the required characteristics for inclusion in the SW Sex category. What they found was that most of these stars are indeed SW Sex stars. Remember, the CV period gap is from 2-3 hours, so these stars may represent an important group of stars, with periods just above the gap, in a high mass transfer state which may cause the binaries to lose contact and stop accreting as they evolve through the period gap.

Boris Gaensicke has become a rock star in the CV community. It is almost unfair to have him start the final afternoon session and then expect three more people to deliver talks on essentially the same topic- 'recent results of CV population studies and the space density of classes of CVs'. I'm just glad it wasn't me, because that is exactly what happened.

Boris hit it out of the park with his presentation. He presented results from the new CVs discovered by SDSS. The main points of his talk are that we've now determined where the missing 80 minute period spike stars predicted by CV theory are. Paula Szkody and SDSS have found them down to around 19th magnitude. They do exist, and they are significantly different from the rest of the CV population.

The spectra of the majority of these stars reveal slowly accreting, white dwarf dominated, WZ Sge-like stars. But, we have still not found the "period bouncers"; those stars with periods less than 80 minutes that are near the predicted 65 minute limit where these CVs will begin to evolve back to longer orbital periods. Boris says they will be found if we just dig another couple magnitudes deeper, and I believe him.

Wild Stars- Day Three

For those of you who came in late on this one, I am in Tucson, Arizona, attending a conference on cataclysmic variables called Wild Stars in the Old West. It has been ten years since the last American CV conference, and five years since the last international CV conference. I wouldn't have missed this for the world. CVs are my thing.


Not only that, but this conference's attendees list is a literal who's who of the CV research world. I am having a ball. Writing all about it has been a pleasure too, even if I have to stay up well past midnight local time to get it done.

Day three featured talks on Magnetic CVs, Accretion Disks and Symbiotic Variables.

The morning session began with Kent Honeycutt showing results of time-resolved spectroscopy of He I and H-alpha lines in BZ Cam. He showed some slick animations that illustrate wind events in the system. Axel Schwope's paper investigated the physics of hard x-ray emitting shocks in Polars using the XMM-Newton satellite. I also learned some new acronyms in common use in Polar research. LARPs, HARPs and PREPs. Low accretion rate polars, high accretion rate polars, and pre-polars respectively. You really have to keep up with the acronyms around here or you won't have a clue what they are talking about!

David Buckley gave an animated, and at times humorous talk on the Southern African Large Telescope (SALT) and its fantastic suite of instruments, capable of doing high signal to noise time resolved photometry, spectroscopy and polarimetry. He also gave some honest insight into the pressures and demands of launching a sophisticated instrument program like this and its affects on the stressed out astronomers.

Polars were the prevailing topic in the morning sessions. Fred Walter showed results of nearly continuous coverage of EF Eri with the SMARTS telescopes since 2003, and an overview of the long term behavior of the system since the 1970's and 80's. Paul Mason explained how highly magnetic polars like AT UMa emit at radio wavelengths. It turns out that accretion disks may actually squash radio emission, so the lack of an accretion disk in polars allows radio waves to be detected from these CVs outside of an outburst. Domitilla de Martino summarized results form XMM-Newton observations of Intermediate Polars (IPs). She also pointed out some of the similarities between IPs and Polars.

After lunch we delved into the hearts of magnetic CVs and accretion disks. The first talk described an exceptionally long Chandra observation of EX Hydra and all the science they were able to glean from such a high signal to noise X-ray spectrum. They were able to explore the emission lines formed in the accretion column as well as first time ever views of a broad component that represents photo-ionization of the accreting column.

I think its amazing how these guys can glean so much science out of 140 hours of time on a space telescope. They were also able to tell the size of the accretion spot and the height of the shock area. All this from an x-ray spectrum!

Chris Mauche reported on a multi-wavelength campaign on the amazing star AE Aquarii. The combined radio, optical, UV, x-ray and gamma-ray results were presented eloquently. Chris is an excellent speaker and a brilliant astronomer. Knox Long described in detail his observations of the structure and source of winds in cataclysmic variables. The end result being, our current understanding is just about right.


The talk that generated the most interest and discussion day three was Graham Wynn's talk on RS Ophiuchi and CVs with massive white dwarfs, giant secondaries and massive accretion disks. He had six movies running at once, a conference record, demonstrating the fact that no matter what the rate of accretion, a disk was formed from the secondary wind. He then suggested some unique solutions to dramatic outbursts RS Oph and objects like it.

Big red secondaries and binaries with long periods remained the objects of interest for the last two talks on symbiotic variables. These interacting binaries present their own challenges to astronomers trying to understand binary evolution.


After the sessions were over we all piled into four buses and rode to dinner at a western steak house in Tucson. It was a fitting scene for a conference about wild stars in the old west. 13 hours after heading to the observatory I found myself walking back to the hotel in the crisp dry evening desert air. I woke up the next day with vague recollections of a dream about Willie Nelson (or was that Steve Howell?) and supernovae.

Wild Stars Pictorial Review Continued

This is Koji Mukai and Domitilla de Martino. Koji is one of the leading experts on intermediate polars in the whole world. Domitilla is also involved in IP research and presented a paper on results from the space X-ray observatory XMM Newton. For those of you who thought astronomers were geeks with no looks or personality, these two will shatter your ill-conceived notions in a matter of seconds.

Axel Schwope is another brilliant and entertaining astronomer using XMM Newton and other telescopes to examine some of the brightest polars in x-ray, optical spectroscopy and optical cyclotron spectroscopy.

I wonder what he tells people at parties when they ask him what he does?


You think astronomers don't have a sense of humor? You might be wrong. David Buckley shared this political cartoon from South Africa starring the SALT telescope. He was also brave enough to share this photo of himself in 'trying to get to first light' mode.

He really looks like Saddaam Hussein out of the foxhole.





Below, a rare sighting of Boris Gaensicke (left with pony-tail) actually sitting still!
He was chair of the session on this day. Here he is seen enjoying the talk from David Buckley (right), who looks much better with a shave and a bath.


Nerd Herd- here is a typical coffee break at the conference. The weather has been absolutely fabulous. Everyone enjoyed the outdoor courtyard gatherings in between papers.

Christpher Tout sharing ideas and sunshine during the break. Later, I pulled him aside to do an interview for a podcast. He was great.


Paula Szkody and friend discussing the merits of the poster in front of them. Paula also graced us with an interview for the podcast.

We talked about SDSS results and what is in her future. In a word- LSST. For those of you who are acronym challenged, that is the Large Synoptic Survey Telescope.





More polar humor. EF Eri is known mostly for the fact that it doesn't do anything most of the time. It's not accreting and we can examine the secondary star because there is no accretion light contribution in the way.

A little Star Trek humor lightens the mood.

Astronomy nerds can be fun...

Can Visual Astronomers Still Contribute to Science?

Today's episode of the 365 Days of Astronomy Podcast examines the controversial issue of the scientific value of visual observations.

Entitled Can Visual Observers Still Contribute to Science? we examine the consequences of living in an age with CCDs and automated sky surveys, and the impact they are having on visual variable star observers.


Restless Universe is the podcast of the American Association of Variable Star Observers (AAVSO).

Variable Stars and the Stories They Tell

The AAVSO podcast is featured on 365 Days of Astronomy again this month.

Today we look at the many reasons variable stars are so interesting to astronomers and the impact variable star research has had on astronomy.

Stellar Evolution
The study of variable stars permeates all branches of astronomy, but first and foremost, the study of variable stars is all about the secret life of stars. How they are born, the way they live and interact with the space around them, how they evolve throughout their lifetime, and ultimately, how they die.

So, what are stars and how are they formed?
A star is a massive object, typically comprised of mostly Hydrogen gas. In the beginning, a star condenses from a cloud of interstellar gases. This cloud gets perturbed enough by some external force that slightly denser pockets of material begin to form within it. Gravity causes these pockets to contract and as their rotation speeds up, causing in-falling material to form a disk we call an accretion disk. Eventually, there is a massive protostar at the center of this rotating cloud surrounded by a lumpy disk that will either be blown away by the star�s wind or become planets.

This protostar continues to grow, and after perhaps 100,000 years or so it is massive enough for nuclear fusion to ignite in its core. From this point on, the life story of our star is the perpetual balancing act between the force of gravity�s contraction and nuclear burning�s expansion trying to blow the star apart.

T Tauri stars are pre-main sequence stars that have recently emerged from this opaque envelope of stellar formation. Our own Sun presumably passed through this T Tauri stage some 4 1/2 billion years ago. Therefore, these stars offer us a peak into the early history of our own Sun and solar system, as well as other planetary systems.

Fortunately for us, most stars live out the majority of their lives peacefully converting hydrogen to helium for billions of years without any major fluctuations or changes. But as stars age and have converted more and more of their original mass from hydrogen into helium, changes begin to take place internally that change the size, temperature and behavior of the star.

As they approach middle age, many stars begin to swell as a reaction to their changing internal structure. A star like our Sun will increase its diameter by a hundred times or more, becoming what we call a red giant. Many of these red giant stars are variable stars, changing in brightness more or less regularly as their atmospheres expand and then contract on timescales of months or years. We�ve learned a lot about star�s internal workings, their atmospheres and stellar winds by studying pulsating red giants.

The stellar aging process also creates some of the most intriguing and beautiful celestial objects. Planetary nebulae are formed when a red giant star ejects its outer layers as clouds of luminescent gas. The Ring Nebula in Lyra and the Cat�s Eye Nebula in Draco are examples of the death throes of swollen, giant stars.

Even this phase is just a fleeting moment in the star�s history. In the end, the nebula will dissipate, and all that is left of our once proud star is a tiny, dense, hot white dwarf, the remnant of the core of our old, evolved star. 95% of all stars that we see in our own galaxy will ultimately become a white dwarf. That includes our Sun.

Not all stars expire so gracefully. Some super-massive stars die in violent explosions we call supernovae. These catastrophic explosions destroy the star and the energy released in the blast can outshine the entire galaxy the star resides in for weeks on end. The famous variable star Eta Carinae may be destroyed one day in exactly this manner.

One of the bi-products of all these dying stars is the heavier elements in the universe that make up our planet, the oceans, the atmosphere we breathe and the very stuff we are made of. All the heavy elements in the universe were created inside the bowels of stars that have long since blown up or blown off their atmospheres. We are indeed �stardust�, and we owe our very existence to variable stars.

Properties of Stars- Distance
Variable stars also reveal a lot about stars in other ways. Take distance, for example.

Astronomy is all about the distance to things in the universe. Variable stars are inextricably woven into the story of our determining the distances to stars and other galaxies.

For many years, the best tool in the astronomical tool bag was the Cepheid period-luminosity relationship. Cepheids are very bright, massive variables with periods of 1 -70 days. The longer the period of the Cepheid, the more luminous it is. Once we know the period of the variable, we know how bright it really is, its absolute magnitude. When we measure a star�s apparent magnitude, how bright it looks to us from a great distance, and compare it to its absolute magnitude, we can calculate the actual distance to the star mathematically. This allows Cepheids to be used as �standard candles� for distance determination. Edwin Hubble used Cepheids in the Andromeda galaxy to make the first estimate of its distance, which led to the realization that it was another galaxy in its own right, hundreds of millions of light years away, and not just a nebula in our own galaxy.

Supernovae are used in much the same way today, to measure the distances to galaxies billions of light years from us.

Mass
Mass is the most important quantity of a star. A star�s initial mass largely determines its life cycle. Large, hot stars use up their fuel quickly and may only live for millions of years. Small miserly red dwarfs burn up their resources slowly, and may last for tens of billions of years.

But how do you weigh a star?
Binary stars are of great importance to astronomers because they provide the only means of directly determining the masses of stars other than our Sun. To find the mass of a binary system we need to apply Kepler's Laws. One of the important pieces of information we need to obtain to do this is the period of the stars orbiting each other. Fortunately, eclipsing binaries, another type of variable star, reveal the orbital period of systems by dimming periodically as one star passes in front of the other. Using this information can yield the total mass of the system and from there we can determine the masses of the individual components of the binary.

Nowadays we are using this same method to study planets around other stars. By measuring the minute dip in light output from a star as a planet passes in front of it from our point of view, and then figuring out the orbital period of the planet by observing multiple eclipses, we can determine the size, density, mass and other characteristics of these extra-terrestrial planets.

Binary star evolution can take some pretty wild turns off the normal evolutionary path of single stars. This is another important branch of astronomical research, and nearly all the players in this game are exotic variable stars of one type or another. The evolution of one member of a pair may have dramatic consequences for its partner over the lifetimes of these systems, as they exchange mass and evolve from one type of pair into another over time.

Large Scale Phenomena
Variable stars can also give us a better understanding of larger scale phenomena in the universe. For example, accretion disks in cataclysmic variables teach us things that can aid in our understanding of star formation, planet formation, galaxy formation, active galactic nuclei and the environments close to super-massive black holes in the hearts of distant galaxies. Because these variable star disks are so much closer and brighter than the disk around a distant black hole, they are easier to study and model.

Variable stars are everywhere. They are spread throughout our galaxy, they reside in other galaxies and they are interwoven into the history of our understanding of the Restless Universe we live in.

To find all the episodes of Restless Universe click on the logo below and you will be magically transported to the Restless Universe page on the AAVSO site.

Spica...the rest of the story

Spica, also known as Alpha Virginis, is the brightest star in the constellation Virgo. Because it lies on the ecliptic, the path of the Sun, Moon and planets across the sky, it is sometimes occulted (eclipsed) by the Moon.

Other than on those occasions, to the unaided eye Spica shines constantly at magnitude o.98, making it the 16th brightest star in the sky. But like so many other stars you wouldn't suspect are actually variable stars, Spica is much more than meets the eye.

As a side note, five of the top sixteen brightest stars are variable stars. They are Betelgeuse, Hadar, Aldebaran, Antares and Spica.

Spica is an interesting case, because not only does it pulsate, causing it to fluctuate in brightness, but it is part of an exotic pair of stars doing a cosmic dance in very close proximity to each other.

Spica is an ellipsoidal variable. Ellipsoidal variables are binary systems where the two components are close enough to distort their shapes into elongated, egg-shaped stars. As they rotate around each other they show us varying amounts of combined surface area. When we see them both from the side we see the maximum amount of surface area. Since brightness is directly related to the amount of surface area throwing light our way we see the pair at its brightest when we see them both from the side. When they rotate around to the point we are looking at them from the end of one or the other star, we see the least amount of surface area shining at us, so the star appears slightly dimmer.

The time it takes to go from bright to faint and then back to maximum light can be measured, and this in turn tells us the period of rotation of the system. In Spica's case, that's about four days. Keep in mind though, these variations are not really detectable without using photoelectric photometry or a CCD. Spica varies from 0.92 - 1.04 magnitudes, too small a change to record visually.

This might seem like a small, insignificant thing to note or study, but consider these facts. The primary component of the pair is 11 times more massive and 8 times the radius of our Sun. Its smaller partner is 7 times as massive as our sun and 4 times as big. These two massive stars spin around a common center of mass so quickly that it only takes 96 hours to complete a cycle. Their combined light output is on the order of 15,000 times the luminosity of our Sun. Its a good thing Spica is a comfortable 260 light years away, or there would be no night time on earth.



Not only does Spica have all this craziness going on, but due to instabilities in its interior, the primary has reached a point in its evolution where it is now pulsating. Yes, its atmosphere is actually expanding and contracting periodically. Beta Cepheids (not to be confused with the better known Delta Cepheids) have periods of 2 -12 hours or so. Maximum light occurs when the star is contracted down to its smallest hottest state, and minimum corresponds to its expanded cooler phase. This variation is also quite small, a few hundredths of a magnitude.

So to the unaided eye Spica shines fairly constantly and only winks at us when the Moon passes in front of it once in a while during an occultation. But to those in the know, Spica is an active constantly changing system, containing two massive stars whipping around each other in space, distorting their shapes into eggs while one of them throws its whole atmosphere up and down in a matter of hours.

As Paul Harvey would have said, "and that my friends, is the rest of the story."

Albert Jones- The Interbiew

Although the quantity of variable star measurements is not as important as the quality, after studying the great observers past and  present, it became obvious to me that to reach 100,000 variable star observations in a lifetime would be quite an accomplishment. There are only a handful of observers who have had the patience, persistence and talent to achieve this in a lifetime.

One of these legendary observers stands head and shoulders above the rest, Albert Jones. Now 89 years old, this quiet, unassuming New Zealander has made over 500,000 variable star measurements over the last 60 years or so. He has received honors from the Royal Society of New Zealand, the American Association of Variable Star Observers, the Smithsonian Astrophysical Observatory, the Astronomical Society of the Pacific, the British Astronomical Association, the Royal Astronomical Society, and has received an Honorary Doctorate of Science from Victoria University in Wellington, New Zealand.

In 1964 he was made one of the first four Fellows of the Royal Astronomical Society of New Zealand, and in 1987 he was awarded an Order of the British Empire (OBE) for his services to astronomy. Minor planet 3152 was named after him in 1988 in recognition of his achievements. If you are involved in variable star astronomy, you know who Albert Jones is. This list of honors and awards does not even begin to tell the whole story. I asked Albert if he would grant an interview, and he kindly accepted. I found Albert Jones, the man, even more inspiring than the legend.

During the process, we sent several emails back and forth. In one of the early ones, I misspelled the word �Interview� in the subject line. Albert was far too kind to ever make note of it or correct it, so we sent several more emails back and forth with �Interbiew� in the subject line. For the rest of my life, I will always remember this as 'the Albert Jones Interbiew�.

Mike: Let�s start at the beginning. Tell us about your parents and family. Do you have any brothers or sisters?

Albert: I was born in 1920 in Christchurch, New Zealand. My mother was such a kind loving person, dedicated to husband and family. Father was a breakfast food miller and head of that department where he worked. There were two brothers and one sister.

When my parents went to school, before 1900, only primary education was free. Secondary education had to be paid for, and like most others, it was beyond their means. Around 1930, when I was at school, primary education was free, then one had to pass an exam to gain two years of secondary education, then another exam to go to the next stage. To go further and to be admitted to a university, one had to pass the Matriculation Exam. I did that at the end of 1936, during the depression years, a time during which there was widespread unemployment, and even people with university degrees had to take on menial work, like digging ditches, to earn a living.

So I found a job instead of furthering my formal education, but that did not stop me from teaching myself from books. Later on, people urged me to retrain in the hope of finding a better job, but by that time I was so hooked on variable star astronomy that I wondered whether I might not have much time for observing if I did better myself, so I was happy as long as I could carry on observing.

Mike: What was it like growing up in New Zealand in the first half of the 20th century? How have things changed since you were a child?

Albert:  I can still remember when the �wireless� was a novelty and telephones were a luxury, and of course, motor cars (automobiles) as well. Roads were made of shingle (stones) and few roads were sealed with bitumen, many vehicles were horse driven.   

When I started school, we were taught writing on slates using slate pencils and as we grew older we wrote on paper using pencils and pen and ink. Things we take for granted now, TV, computers and the internet were not even thought about.

Mike: How did you first get interested in astronomy?

Albert:  From an early age I wanted to know about the sky and stars and planets. I do not know how I became so fascinated by them. All I can remember is that my inquiring mind wanted to learn more. Parents and friends helped me with what they knew.

After I left school at the age of 16, I was well aware of my limited knowledge and never dreamed that one day I might be able to make a contribution to Astronomy, but for my own fun, and to satisfy my curiosity, I could at least learn the constellations and be able to recognize planets. So with the aid of books, I did that.

Then in answer to a request in the newspaper for reports of aurorae, I made detailed notes of the next aurora that I saw, sent it in and was thrilled with the reply stating it was the best report received. So two years later, I timidly asked if there was an astronomy club or society that might accept me as a member. Soon after, I became a member of the New Zealand Astronomical Society (later to become the Royal Astronomical Society New Zealand; RASNZ). Then I started receiving their journal �Southern Stars�.

Mike: I think every astronomer remembers their first telescope. Tell us about your first telescope.

Albert: My first telescope was the crudest thing imaginable. An inexpensive lens kit consisting of what may have been a simple spectacle lens of about 20 inches focus and a small negative lens for the eyepiece. I made a tube for the telescope by wrapping paper around a rod as a pattern, and gluing the layers of paper. Although the images were very poor, it at least allowed me to see things. I can still remember the thrill of seeing the Orion Nebula I had read about in books.

Later a bigger lens kit showed me the rings of Saturn. The tube was a cardboard one that had once been the centre of a roll of carpet. A simple tripod made the telescope usable for viewing objects like star clusters and planets, even the rings of Saturn.

Then I heard that a local man had an old telescope he was not using, so I bought my first real telescope, a 5-inch f/15 reflector, evidently made for viewing planets and the Moon. The finder was so tiny that it was difficult to find faint star fields away from bright stars.

Mike: At some point you decided to start observing variable stars. Tell us about the first variable star you began observing.

Albert: As I mentioned above, the journal �Southern Stars� became available and helped me immensely, especially after the discovery of Nova Puppis 1942, because one of the co-discoverers, a New Zealander named Alex Crust, wrote an article for  �Southern Stars� about the nova. It included a chart with comparison stars plus instructions on how to make estimates of it as it faded.  I did not need any encouragement to look at it each clear night, and after I had made 50 estimates I posted the estimates to Mr. Crust, who wrote another article for the journal and listed all estimates to date. Imagine how thrilled I was to find that not only were my estimates worthy of inclusion, but they compared well with others. Those first observations starting in January 1943 proved that making observations of variable stars was within my capability,

Mike: Frank Bateson, the founder and long-time director of the Royal Astronomical Society of New Zealand's Variable Star Section played a key role in your interest and development as a variable star observer. Tell us about Frank and your relationship with him over the years.

Albert:  Yes Mike, the following year Frank Bateson returned from the Navy to civilian life, and in reply to my request to join the Variable Star Section, he sent me charts of 25 variable stars.  At first I thought that I had bitten off more than I could chew, but as I gained experience in locating star fields, I soon had the 25 stars on target and asked for more stars. The next batch of 43 stars again made me think I had over-done it, but before long I could locate all those stars.

One handicap was the tiny finder. Even now I can remember my frustration one night looking for S Apodis by star-hopping from Gamma Aps, over 3 degrees away! All the intervening stars were too faint to see through the finder. It took me an hour to locate the field. I was determined to find it and did not want to admit defeat.

Mike: You also began sweeping for comets early on, and discovered your first comet in 1946. Tell us about your discovery of Comet Jones 1946h.

Albert: I did some comet sweeping with the old reflector and successfully recovered  Comet P/Kopff, before anyone else, they say. I located it from  the ephemeris in the BAA Handbook.

Then I heard of a 5-inch refractor that was for sale, and that one was far better to use. The finder objective was larger and enabled me to star-hop to fainter fields with confidence. I also used it for comet sweeping.

One morning in August 1946, I had unsuccessfully swept the south-east and found only permanent celestial scenery. I noticed dawn was imminent, so decided to see if I could see U Puppis, as by then the field should be low in the eastern sky. The finder was too high at that position to look through it from standing on the ground, so I hurriedly aimed the main telescope at the region of Puppis using a low power. I swept down to locate the variable, but on the way I noticed a fuzzy object.

I made a quick field sketch, but dawn stopped viewing before I could notice any motion.  I did not get to see the variable that morning. Rather than make a false �discovery�, I waited until next morning. The sky was clouded over, but luckily the clouds moved away in time for me to find the position where the object was the morning before. It had moved away.

I kept sweeping until I located the comet. I notified Ivan Thomsen at Carter Observatory who spread the word. That was Comet 1946h. Soon afterward, I realized that variable star observing was not only more fun but also produced real results right away. So I concentrated on variable stars instead.

The 5-inch refractor was later replaced by an 8-inch reflector made up from bought optics. Aperture fever later led me to purchase a 12.5-inch f/5 mirror, which I made up into the telescope I still use now.

Mike: Your second comet discovery came in 2001, when you were 80 years old. That is quite a long time between discoveries! Not only is that 54 year gap a record, but you are the oldest person to have discovered a comet. What is the story behind your second comet discovery?

Albert: In 2000, I learned that Dr. Brian Marsden was stepping down from head of the CBAT (Central Bureau for Astronomical Telegrams) so I wrote to congratulate him on his retirement. In reply, he told me that he was not retiring and was staying on to support Dan Green who had taken on the position. He mentioned that it was a long time since I found a comet and it was time I found another. But that is easier said than done.

A few months later, I was star-hopping to T Aps when I noticed a strange fuzzy object and made a note of the position. I phoned Alan Gilmore at Mount John Observatory and told him I had seen a comet that morning. I felt sure it must be a known comet that I had not heard about and I asked Alan its name. Alan replied that he had not heard of such a comet, so he reported it to the CBAT. Brian Marsden wondered whether it might be the same comet that Syogo Utsunomiya had seen only once a week before which had become lost. That turned out to be the case. So it now has both our names. Brian Marsden emailed, �I told you what to do!!�

Mike: The home-built 12.5� telescope you have used since 1948 is named Lesbet. That�s kind of an odd name. Who is it named for?

Albert:  That is another story. Back in 1947, I  wanted an even larger telescope and airmailed to Dr. Les Comrie, a former New Zealander who had revolutionized the British Nautical  Almanac Office by replacing math tables with mechanical accounting machines, which he found could be adapted to do mathematical astronomical calculations.

Dr. Comrie was very kind to up-and-coming amateurs. I wrote to him and asked where in the UK could I buy a larger f/5 mirror and he replied that his friend James Hargreaves had a mirror blank that he could grind and figure to f/5, then pack it in a box in time for Dr. Comrie to bring to NZ by ship as he had plans to come to NZ to visit his father in late 1947. That suited me fine as it saved me the bother of getting an import license and permission to send money to England, as well as arranging the freight.

When Dr. Comrie came to NZ he forwarded the mirror to me, I paid for it by sending the money to Dr. Comrie's account in a large business in Auckland. With the money, Dr. Comrie paid for food parcels to be sent to his friends in England who had not seen luxury food during the war, so everyone benefited besides me. I named the telescope Lesbet after Les and his lovely wife Betty. Les always said she had a perfect figure too!

Mike: There was quite a bit of excitement in 1987 when supernova 1987A went off in the Large Magellanic Cloud. You are credited with co-discovering the brightest supernova seen since the 17th century. How did that come about?

Albert: I was monitoring some stars not far from the Tarantula Nebula. On that fateful night, while I was observing stars elsewhere in the sky, I noticed some clouds coming over so I poked the telescope at my targets in the LMC. I was quite surprised to see a bright stranger, so I noted its position on the chart. But before I could make a magnitude estimate the clouds moved over. I phoned Bateson who started phoning others for confirmation. Then the clouds moved away and I made an estimate of the stranger before phoning Bateson again to tell him. He then phoned the Observatory at Siding Spring, in Australia, to tell them about the star. I have been told that everyone at the Observatory stopped what they were doing and turned their attention to the supernova. Rob McNaught then checked the photos he had taken and found the star was recorded on them.  

Rob then phoned Dr. Marsden to say he had a photo of it, but as Brian was already on the phone to Chile, Rob told the secretary. Dr. Marsden then phoned back to Rob to congratulate him on the discovery, but Rob said he was not the discoverer. It was discovered by someone in NZ, but did not know who it was. Dr. Marsden correctly guessed who it might be.

Mike: Perhaps your greatest discovery is your wife, Carolyn. How did you two meet, and how has she supported your passion for the stars?

Albert: My first marriage was such a disaster that I thought of ending my life. Fortunately, I did not and we parted. I vowed never to marry again, but changed my mind after Carolyn joined the same hiking club. I could not help secretly admiring her. Then when two years later, I found out that she thought the same about me, I changed my mind for the better. Carolyn was such a kind, lovable person and so different that I instinctively could tell she would be the ideal person to live with forever. July 2009 was our 25th wedding anniversary- the happiest years of my life.

Mike: How active are you these days? Do you still submit observations?

Light Curves of RU Lupi-

Top curve is AAVSO data without Albert Jones archival observations. 

Bottom curve is the same time period with Albert Jones observations included in the AAVSO International Database.

From the AAVSO 2007 Annual Report

Albert: I continue to observe variable stars each clear night, and besides sending my observations to AAVSO, I send data on selected stars to over 30 professionals worldwide.

I like to start observing as soon as it gets dark, and as I have had lots of birthdays, after observing for 3 hours I become so tired that I have to stop. Then I go to bed and get up again an hour or two before dawn and observe stars that have come up in the east.

The thrill of seeing with my own eye how variable stars change has not palled a bit, and to know that what I report is of value to Science is an added bonus. Especially, on a cold winter morning, when I may feel reluctant to leave a warm bed. Once I have put on a few extra layers of clothes and dragged the telescope out of the shed I feel it is so worthwhile.

 Mike: Even if we knew everything there was to know about variable stars, and therefore no real reason to keep going out night after night to observe them, would you keep observing anyway?

Albert: As long as my well-being and eyesight allow me to get to the telescope, there would be a number of stars that I would like to keep monitoring to satisfy my curiosity and for fun.

Mike: After discovering two comets, a naked eye supernova and making over half a million variable star observations, what is it that still drives you? What else would you like to accomplish or discover?

Albert: Just looking and looking, in case I might discover something, might become boring. So I carry on monitoring stars for Science. And if something new is noticed serendipitously, that would be a bonus. There are lots of my old estimates that were made before reliable comparison star magnitudes became available from sources like the All Sky Automated Survey, so I hope to revise as many as I can while I am still able.

Mike: What is the greatest difference between observing and reporting observations now and in the past?

Albert: Over 60 years ago there were charts for lots of variable stars, some not as good as those available now, so it is good to obtain better charts and finding charts for them. Long ago, one had to draw finder charts from what one saw through the finder. Now finder charts can be made using PC software and printed by modern computer printers.

PCs and software are great for entering the observations from my logbooks, and it is now so easy to sort the individual stars, and select which stars go to whom by email. No longer does it take lots of writing by hand. I could go on and on, but let me just say how lucky observers are today with all this modern technology to take a lot of the drudgery off their hands.

Mike: Thank you for taking the time to let us get to know you.

Albert: Well Mike, I do hope that I have not bored you with all this.

Thinking back over the years, Carolyn and I have enduring memories of the wonderful people who have come into our lives through Astronomy.

I sincerely hope that anyone reading this will realize that serious work can be undertaken with only basic gear. If one has access to a modern telescope with all the bells and whistles, please have a go at variable star observing. But do not despair if you do not have such equipment, as so much needs to be done and can be accomplished with very modest gear. I know- been there, done that. The main thing is to have fun.

Don�t Lick the Telescope, and Other Tips for Cold Weather Observing

December marks the transition here in Michigan from cool fall weather to downright frigid winter temperatures. For most of January, February and March, there is snow on the ground and the daytime temperatures will hover around freezing. Nighttime temperatures will be well below freezing, and on those few precious clear winter nights it can be unbelievably cold.

Here are some cold weather survival tips I have learned, observing from Michigan in temperatures down to 20 below zero Fahrenheit.

   1. Wear warm boots. When I meet people new to astronomy, they always want to know what the best telescope is and what accessories to buy. I always tell them, "The most important piece of equipment you will ever buy is warm boots". When it is clear, it is cold. If your feet are cold, you are miserable. If you are miserable, you are done.

Standing on the cold, damp ground outside you�ll soon know if your boots are up to the task. If they absorb moisture, or don�t insulate you from the cold ground your toes will be crying Uncle long before your favorite Messier object clears the trees.

  2. Always dress for temperatures 20 degrees colder than you predict it will be each night.

For the most part, you are not moving around a lot when looking through a telescope, downloading images from your camera or monitoring your tracking. You don�t generate any heat of your own just sitting there, and the night air has a way of sucking the warmth out of you faster than you think it will.

   3. Wear a hat. Most of the heat in your body escapes through the top of your head like a chimney. Cover your head and retain body heat.

I�ve seen lots of funky looking hats at star parties. Don�t worry about fashion. Go for comfort. My deep-winter, arctic-air-repelling hat is a big leather and fur job with earflaps and a long extension in back that covers my neck. I look like one of the wicked witch of the North�s soldiers in my long coat and that hat, but I�m warm.

   4. Keep your hands warm. Mittens are better than gloves, but they are awkward to use when dealing with focuser knobs, charts, pens and pencils, But if you can keep your fingers together, tucked away from the cold, they fare much better than they do as individual digits exposed to the elements. I�ve never had much luck with those gloves with the flip-top mitten cover for your fingers.

If you insist on wearing gloves, like I do, keep your hands in your pockets and out of the wind, as much as you can. Those little chemical heat packs you can buy in sporting goods stores work pretty well for a while. I sometimes throw a couple in my coat packets to create a safe haven for my fingers for a few moments between variable star observations.

If your fingers begin to hurt from the cold, go inside or get in your car and warm them up thoroughly. Frostbite can be very painful.

  5. Get out of the wind. Most of the time it�s not the air temperature that gets you, it�s the wind-chill. Put a building or a hedge, or better yet, an observatory, between you and the wind and you will be able to endure the cold for twice as long. The added bonus, of not having the telescope shake in the breeze, will save you time in making critical observations.

I remember very well the night that convinced me to build an observatory. It took twice as long as usual to set up wearing gloves, I dropped a small wrench in the snow and spent half an hour looking for it, the telescope was shaking so much it was hard to see anything in the eyepiece, my eyes kept tearing up from the wind and dropping tears onto the eyepiece lens, and the wind kept blowing right up my back as I faced south trying in vain to make variable star estimates.

I spent three hours out in the snow and wind and got exactly one variable star estimate that night. That week I became the proud owner of a fiberglass, domed observatory.

   6. Don�t breathe on optics. Breathing on cold glass means instant frost. If you wear a scarf over your face, be sure not to let the warm air you exhale spill out over the top of the scarf and down onto the eyepiece.

Set up your finder-scope so you are not breathing on the eyepiece when looking through the finder. On very cold nights, I sometimes have a large patch of frost on the back of the mirror cell of my Schmidt-Cassegrain, caused from my breath freezing on the back of the telescope while looking through the finder-scope.

   7. If you have dew heaters, use them right from the start of your session. They are much better at preventing frosted corrector plates, secondaries, eyepieces and finders than they are at removing frost. If you don�t have dew heaters, get them.

A heated box or holder for eyepieces can be a great benefit. If you only switch between a few, keep them in your pockets to stay warm.

Another accessory I find handy is a small hair dryer. If you have electricity available, one of these can be great to warm the eyepiece up enough to prevent fogging. If the lens or corrector plate on your telescope frosts up, you can use it to carefully remove the dew or frost.

You can also use it to warm your fingers. I�ve even stuck mine inside my coat to warm my frozen torso enough to go a little while longer. I�m sure this is a fire hazard, and you�ll probably read in the paper one day, �Michigan astronomer mysteriously ignites into flames, burning down observatory.�

   8. If you take notes at the telescope like I do, keep your pen warm or the ink will freeze. I have one of those "astronaut pens". Even that froze at 20 below.

I keep my pens tucked behind my ear to keep them warm. All my observing hats have a distinct black ink spot on the inside lining, just behind my left ear, from me continuously sliding my pen in and out under my cap and over my ear for warm storage.

   9. Use a plastic flashlight. If you are like most of my friends who read charts and log observations using a red flashlight, you put the flashlight in your mouth to write. On very cold nights, a metal flashlight can stick to your lip and be hard to remove without losing a bit of flesh.

Don�t laugh; I�ve seen it happen!

I suppose rule 9A should be, "don�t lick the telescope!"

If I ever see anyone get his or her tongue stuck to a frozen telescope, you�ll be the first to know!

   10. Take breaks every hour or half hour, depending on the weather, and go warm up. Keep an extra pair of dry socks warming on the dash of your car, or go in and throw a pair in the dryer for a few minutes. It�s amazing how a nice toasty pair of socks can change your attitude!

I�ve received several pairs of electric socks for Christmas and birthdays over the years from well-meaning friends and family, but I�ve never been really impressed by them. Considering the number of batteries it takes to actually keep your feet warm, it�s just not worth it. Refer to rule #1. Wear warm boots.

  11. Be aware of battery life in cold temperatures. The batteries in your flashlight, telescope, camera, dew heaters, etc., will perform poorly in cold temperatures. They�re smarter than me. They know when to quit. Keep warm extras handy.

  12. Keep your own personal battery charged. Plenty of rest, a good meal, snacks and hot coffee go a long way towards warding off the inevitable freeze.

The search for a thermos that would keep coffee hot in sub-zero temperatures was my �Holy Grail� for a long time. After years of searching, I finally found one at a camping supply store. It cost a pretty penny, but it makes all the difference to me.

  13. Know your limits. You have to be realistic about how much cold, discomfort or pain you are willing endure in order to get those last few observations. Don�t wait until it�s too late and then decide to tear down and pack up.

When you are really frozen, you fingers don�t work right, you move slower, you feel more tired than you normally would, and you can get careless, dropping things in the dark or forgetting how to pack your gear just so. All this means it is going to take you longer than usual to tear down.

That�s when you will meet Mr. Frostbite. It is better to take my word for it than to learn a painful lesson from him.

With a little planning and common sense you can take advantage of those long, clear, cold winter nights. Orion, Gemini and Taurus are calling. Just be careful out there.

Help! I Want To Study The Stars

Getting started in the hobby of astronomy can seem overwhelming. I mean, it is the study of the Universe! That's a pretty staggering concept. There is so much to learn; constellations, the motions of the stars, Sun, Moon, planets, just getting the names and pronunciations right can be tough without some good help, or a mentor.

Most observers start out in just about that order, it's a natural progression. Once they've learned their way around the sky and can name many of the bright stars and constellations they gravitate towards the Moon and planets. For many of us, that first magical look through a telescope at Saturn and her majestic ring system is all it takes to get us hooked for life.



Soon after purchasing their first telescope, most amateur astronomers begin seeking out deep sky objects, like the Messier objects. Locating them and learning how to discern the subtle detail available in the eyepiece is a fun and rewarding experience.

Most people find that adding to their understanding of the objects they observe adds to the enjoyment. Knowing that the planetary nebula you are looking is the gaseous remains of an old stars atmosphere, glowing in space due to the energy released by the white dwarf in its center makes them even more exciting to observe. Soon, reading astronomy books and magazines, even astronomy blogs!, becomes a regular activity.

The variable star AE Aurigae is embedded in the Flaming Star Nebula, aka IC 405.
Photo credit: Jorge Garcia, Astronomy Picture of the Day

For me, it was the things that changed from day to day, or even in the course of a few hours, that were always the most interesting things to observe. Watching sun spots rotate around the solar disk, tracking the changing orientation of the Galilean satellites from night to night, watching a prominent feature on Mars rotate out of sight and watching the Moon pass in front of a bright star or planet has always been the biggest thrill for me. Proof that the Universe was alive with motion and packed with action I could see with my own eyes or in a telescope.

Many amateurs can continue on chasing after ever fainter, more elusive 'faint fuzzies', or spend the rest of their life perfecting the technique of obtaining the perfect image of a galaxy or star cluster, but for some, they reach a fork in the road, where they decide they want to actually contribute to science in some meaningful way. For many of these amateur scientists, variable star observing (VSO) provides the answer.


Getting started in VSO presents many of the same challenges as starting out in general astronomy. You need to be able to find your way around the sky, learn the terminology, and learn how to get the most out of your equipment and what the limitations are. And just like other astronomical pursuits, its a lot more fun if you understand what it is you're looking at and why it is interesting to professional astroomers.

Fortunately, the AAVSO has a program for beginning observers, the AAVSO Mentor Program. The AAVSO has a long tradition of experienced observers helping new observers learn the ropes of VSO. Many of us can trace our knowledge back several generations to some of the most prolific and famous amateur observers of all time. Even William Tyler Olcott, the founder of the AAVSO, started out by learning VSO from another observer.


The mentor program has volunteer instructors in the US, Canada, Europe, South America and Australia. There are mentors for visual observers just stating out and knowledgeable amateurs who can teach you to use a CCD or photoelectric photometer.


"...it is a fact that only by the observation of variable stars can the amateur turn his modest equipment to practical use, and further to any extent the pursuit of knowledge in its application to the noblest of sciences."

William Tyler Olcott, March 1911

If you'd like to turn your modest equipment to practical use observing variable stars, and want to get off to a good start, contact the AAVSO, or email me at mikesimonsen at aavso dot org to request a mentor to help get you started.

Most observers start out doing VSO because they want to contribute to science. The observers who stay with it for years and years do it because its a lot of fun. So come on and join in the fun, but be forewarned, you may get hooked...

"I feel it my duty to warn any others who may show signs of star susceptibility that they approach the observing of variable stars with the utmost caution. It is easy to become an addict and, as usual, the longer the indulgence is continued the more difficult it becomes to make a clean break and go back to a normal life."

Leslie C. Peltier, Starlight Nights, 1965

Telescopic LPVs for New Visual Observers

Okay, so you�ve been observing some naked eye and binocular variables for a while. Good for you! The stars in the AAVSO Ten Star Training Program can be fun and rewarding to observe for a lifetime.

Maybe you were drawn in by the Citizen Sky project and now you�re getting hooked on variable stars. Hey, it happens; you are not alone. But epsilon Aurigae is in full eclipse now, and will remain faint for most of this year, so maybe you�re ready for some new stars to satisfy your new addiction.

Perhaps you already owned a telescope or you finally got that shiny new 8� Schmidt-Cassegrain you�ve had your eye on for Christmas. Now where do you look for interesting variables? I�ve got some suggestions for you. These are fun stars to observe, AAVSO still needs observations of these stars, and best of all, they are easy to find and identify, so you won�t spend cold winter nights looking for them. You can spend your time observing them instead!

R Aur- After you make your observation of epsilon Aurigae for the night, (because you should keep observing it all the way to the end of the epsilon Aur campaign!) use your telescope and finder to star hop over to this great long period variable. I think of this one as the �Pirate Star�, because its name is �Arr, Arr!�

There are plenty of magnitude 6 to 9 stars in the area to help point the way, making this one easy to find. Varying from 6.9-13.9V, it also happens to be an interesting double star! R Aur is on the rise from minimum right now, so it will get easier as winter turns to spring.

R Cas- This Mira gets as bright as 4.7, and can fade to 13.5. R Cas is currently on the rise from around 10th magnitude so it will be easy to observe all winter.

T Cas- When at or near maximum, this is one of the reddest stars you�ll ever see in the eyepiece. This Mira varies from 6.9-13.0V and has a very interesting light curve with multiple humps, perhaps indicating multiple periods. Currently around 9th magnitude, but is it rising or fading? Have fun following this one!

T Cas has humps like a camel in its light curve. What's up with that?

V Cas- This Mira has a pretty regular period of 228 days. Ranging from 6.9-13.4, V Cas is currently at minimum, so it will become easier to observe as winter progresses and it brightens.

S Per- Sitting in a beautiful star field with plenty of 8th and 9th magnitude stars to point the way, this interesting semi-regular variable, varying from 7.9-12V, is somewhat unpredictable, so you never know what it will be doing next time you observe it.

W Tau- Located in the Hyades, just west of Aldebaran is a bright double star consisting of theta 1 and theta 2 Tau. In the same medium power field of view is W Tau, a semi-regular variable that ranges from 8.2-13.0V. The period is listed as approximately 165 days, but this star is unpredictable, and the light curve for the last 1200 days is chaotic. This, plus the fact it is easy to find and observe, makes W Tauri a fine catch on a cold winter night.

W Tau is close to a beautiful double star in the Hyades cluster. You gotta be able to find this one!

There you go; a half dozen stars to add to your variable star program. If you�re looking for more you can check out the Stars Easy to Observe list on the AAVSO website at http://www.aavso.org/easy-stars

If you run into trouble, or just want some friendly advice from an experienced observer, contact me at mikesimonsen at aavso dot org. I coordinate the AAVSO Mentor Program and I can hook you up with one of our great mentors to help give you a boost up the learning curve.

T Scorpii, Our Long Lost Friend

On May 21, 1860 a nova burst forth in the constellation Scorpius. This nova was notable in the fact that it seemed lie either in or in our direct line of sight with the globular cluster NGC 6093, also known as Messier 80 (M80). At peak brightness it shone at magnitude 7.0, brighter than the rest of the entire cluster. It faded more rapidly than a 'typical' nova and disappeared. The nova was given the variable star designation T Scorpii and hasn't been seen or heard from since.

In recent years, studies of globular clusters have yielded some surprising results, among them a class of stars called 'blue straggler stars'. Blue straggler stars (BSSs) are stars observed to be hotter and bluer than other stars with the same luminosity in their environment. As such, they appear to be much younger than the rest of the stars around them.  This presents a problem for stellar evolution theory, since all the stars in a cluster ae believed to have formed at roughly the same time, so they should all be the same age and have evolved differently mainly (if not only) because of their initial mass.

The three main theories suggested that could produce such stars are: (1) collisions between stars in clusters or (2) mass transfer between, or the merger of components of short-period binaries, or (3) the progenitors of BSSs are formed in primordial triple star systems. Processes such as tidal friction might create very close inner binaries. Angular momentum loss in a magnetized wind or stellar evolution could then lead to the merger of these binaries, or to mass transfer between them, ultimately producing BSSs.

Messier 80
Credit: NOAO/AURA/NSF

Star clusters, both open and globular, are great astrophysical laboratories for astronomers, because all the stars are assumed to be at roughly the same distance and approximately the same age, so differences in the population of stars are assumed to be real, not the result of how far away they are or how old. These blue stragglers are just one hot topic that has caused astronomers to look at clusters like M80 much closer with space telescopes like Chandra and Hubble space telescopes.

Recently, astronomers studying stellar populations in M80 in the ultraviolet, using the HST, were able to identify most of the known x-ray sources in the core of the cluster. While the main point of their investigation was to study the populations of BSS's, one of these sources happened to be a dwarf nova in outburst at the time of the observations. More interesting than that, it appears to be consistent with the location of the 1860 nova, T Scorpii. Given its position, X-ray and UV brightness and variability, this source is almost certainly the true counterpart to T Sco. After 150 years we have finally found an old friend.

Welcome back, T Scorpii.