MUSIC IS MY SOUL

Now that it is done, I am feeling a mix of relief and sadness. Relief- because four days of intensive research results presented session after session is like cramming a semester's worth of astronomy into your brain in four days. Sadness- because I could take maybe one more day, just to finish meeting and talking with some of the people I really wanted to talk to one on one. There just wasn't enough time. I think this was the most worthwhile, well-organized and relevant conference I have ever attended.

I'm not knocking any of the organizers of variable star meetings I've been to in the past, but this was all about CVs, all the rock stars of CV research were here, and I had back stage passes. It was frakkin' cool. The last day of the conference was all about things I am interested in- TOADs, Recurrent Novae and Classical Novae.

The talks of the day were also book-ended by two impressive astronomers from Japan's VSNET, Daisaku Nogami and Izumi Hachisu.

First thing in the morning session Daisaku Nogami presented impressive results of the superoutburst evolution of three very interesting CVs- WZ Sge, GW Lib and V455 And. These are three of the most significant outbursts of dwarf novae in the last couple years and Nogami had it all nailed down. The following talks on GW Lib and V455 And were almost redundant after the impressive amount of optical photometric and spectroscopic information Daisaku presented first thing in the morning.

The last talk of the morning session was about the source of negative superhumps, by Michele Montgomery. I had the pleasure of meeting her and talking for an hour or so Tuesday night, at the NOAO reception. She is an excellent presenter and had a great talk, chock full of teasers about her upcoming publication.

You just have to be intrigued by a woman who can teach you all about the minimum accretion disk tilt needed to generate negative superhumps in light curves, the parameters that affect negative superhump signal strength, and the location in the disk that contributes to this phenomena. That is sexy stuff!

Not to dismiss the other presenters who talked about classical novae and recurrent novae after lunch, but Brad Schaefer stole the show with his talk. Brad does not need a microphone to be heard in a room of 200 people. He is enthusiastic and knowledgeable about his topic, recurrent novae, and he knows how to work a room.

Some of the most exciting news from Brad were previously undiscovered eruptions of RN in past years. He and his graduate assistant relentlessly scoured all the archival data in the world to find plates and observations of recurrent novae outbursts. They found three eruptions of U Sco (1917, 1945, 1969) RS Oph in 1907, V2487 Oph in 1900 and CI Aql in 1941.

From these intensive searches, and modeling the results, Brad is able to make some bold predictions about the timing of future eruptions. In the next decade he predicts no less than five recurrent novae eruptions- V2487 Oph, V394 CrA, V745 Sco V3890 Sgr and the one he is most excited about U Sco. U Sco is predicted to erupt in 2009.3, which is RIGHT NOW!
After lunch we were shown amazing results of x-ray observations of recurrent novae and novae. There is a lot of interest in novae eruptions by professionals, more than I realized. What's more, they are making x-ray observations of these objects months and years after the initial outburst in an attempt to observe just when the accretion disk reforms and accretion begins again and what happens at this phase of the outburst.

From this I realized, amateurs need to follow many of these objects for much longer than we typically do as best we can. The AAVSO light curves sort of peter out after six months or so, and rarely is there much follow-up when a star reappears from solar conjunction. It's like we've all forgotten about them and moved on to the next big thing. Unfortunately, this is about the time they become really interesting to professionals, and from what I was seeing there may be some very interesting observational phenomena we are totally missing, like sudden rebrightenings of the systems or flickering. Amateur CV sleuths take note!One of the final talks of the conference was from Izumi Hachisu. He presented the methodology and results of his search for a relationship between the t3 time of decay (the 3 magnitude decay time from optical maximum) and the turn-on and turn-off times of supersoft x-ray emission. He presented detailed light curve analysis of classical novae detected in x-rays, and proposed best fit models that reproduce the optical and supersoft x-ray observations. If all that sounds impressive, you're right, it was. The fact that most of the data was collected with relatively small telescopes makes it that much more impressive.

That's about all I can dig out of my CV overloaded memory and notes at this point. I'm going to let this all digest for a day or two and write a summary review. I know I am looking forward to the next CV conference, which is planned for 2010 in Kyoto, Japan!

As promised, the interviews I did with five astronomers at the Wild Stars in the Old West II conference are now coming online, thanks to my friends at Slacker Astronomy, Michael Koppelman and Doug Welch. The first part of the series is now available.

The first interview in this episode is with Brad Schaefer from LSU. Brad is very excited about the results of his research on recurrent novae. These cataclysmic variables grab our attention and spark our imaginations because of the incredible amplitude of their outbursts, typically 8-12 magnitudes, and the rarity of these spectacular events. Many of these outbursts are once-in-a-lifetime events. Like an apparition of Halley's comet, witnessing an outburst of T CrB twice in a lifetime would be a matter of uncommon luck, longevity or both.

I've written about recurrent novae before. The cause of a nova eruption is a thermonuclear reaction on the surface of the white dwarf. After years of mass exchange between the binary pair, temperature and pressure at the surface of the white dwarf build sufficiently to cause the layer of accreted material to explode like a hydrogen bomb. This bomb, however, can have the mass of 30 Earths! Once the temperature becomes high enough, this layer begins to expand. Minutes into the process the shell can be radiating at 100,000 solar luminosities and expanding outwards at 3000 km/s. Eventually the shell envelopes the entire binary and the orbital motion of the pair acts like a propeller to whip things up. After 1000 days or so the envelope expands to the point it can be seen as nebulosity surrounding the pair. Over hundreds of years the shell dissipates into the interstellar medium.

Most novae probably erupt more than once in their lifetime, with the mass of the white dwarf determining the amount of accreted material that needs to accumulate before triggering on outburst. Systems with a white dwarf of 0.6 solar masses might take as long as 5 million years between eruptions. A system with a 1.3 solar mass white dwarf might only take 30,000 years between eruptions. Systems with recurrence times of 100 years or less probably have very massive white dwarf primaries.

With so few known examples and the rarity of these events it is no wonder that recurrent novae eruptions are extremely interesting to astronomers. Monitoring these stars for outbursts over decades of relative inactivity is still one of the extremely valuable contributions visual observers can provide to science.

The second interview is with Steve Howell, of NOAO. Steve and I talked about the advances that have been made in CV research since the last Wild Stars meeting ten years ago. I also asked him where he thinks new research is heading.

But, I have to admit, I really wanted to talk to him about his awesome image of magnetic accretion. I saw this in his poster presentation at the meeting and was blown away by the whole concept of the complicated, beautiful way mass is accreted in polars.