MUSIC IS MY SOUL

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.

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.

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.

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!


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.

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!

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.

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.

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...

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).

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, 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."