Today I joined to a live webcast a friend told me about.  It was put on by a group of amateur astronomers, but very interesting and professionally done. The title was Advanced Spectroscopy, so I didn’t really know what to expect.

It started off with a description of the speakers amateur setup – some amateur setup! I think there are some colleges that would consider themselves privileged to have such equipment.

Dale Mais was the speaker. He calls himself an amateur but I suspect the only difference between him and a professional is that he gets paid for doing something else. He was very knowledgeable and has published several astronomy papers.

http://www.mais-ccd-spectroscopy.com/

So what’s he doing? Let’s see if I can remember correctly, no guarantees however. Basically, Dale is measuring the emission spectra of  Mira stars, which are red giants and reside on the asymptotic branch of the Hetzsprung-Russel diagram. They’re also called long-period variable stars because their luminosity varies with a period of 100 to 1000 days or so.

He mentioned that contrary to what many popular publications say, heavy elements could come from such stars. Once people thought the Big Bang produced heavy elements and later suggested that they came from supernovae. But he says they can really be made in Mira stars and suggests some nuclear equations. Someone a while back detected an isotope of technetium in such a star (half-life is such that it had to be made in the star; could not be hanging around from formation).

He has an automated setup that can collect data all night long. He said he had 87 DVDs worth of data. Over 3.5 years he detected very few flares and estimates just one every 20 years per star. I guess not having a flare means that measuring emission spectroscopy is not that useful, so he concentrated on photometric measurements. He detected a knee in the luminosity curve of some Mira stars.

I don’t know if luminosity curve is the correct name for this, but I think the graph is like brightness vs. time where time is the period; and so you overlay the graph with each period, and for some stars you see a knee progress to the right and then reappear on the left. Other stars overlay the knee exactly.

Dale and a colleague are currently writing this up, but hoping to find a theorist to help them explain the knee. He suggested something like an oscillation that reflected off a stellar core.

The web conferencing software was www.ivocalize.com . It worked well, but it is not a desktop sharing program. Basically, it allows a presenter to share slides and talk. Attendees can write text messages or talk. Writing a text message seems to be considered more polite than interrupting.

I participate is some other meetings where we really do need desktop sharing. We want to share running programs and do collaborative debugging for example. For desktop sharing, I’ve used www.gotomeeting.com which is excellent. (It’s not free, but certainly affordable for a company, like $50 a month). We use www.skype.com for conferencing audio, which is free.