Affiliation
American Association of Variable Star Observers (AAVSO)
Sat, 04/11/2015 - 23:29
Is there any value in 600L (Alpy600) spectroscopy of LPVs during maximums? I know that some show emmission lines, but are such data of value and needed at this low resolution (i.e., 500-530).
Ed
This is a far deeper and apropo question than you may have recognized.
The shortest answer is that it depends on the type of variable. The literature can give some clue as to what spectral changes may occure over the cycle. But how much utility a low res spectrum has is at least I some cases, not well determined.
I have one of my students right now working on a pilot study to track the cycles in longer period Mira variables using SA200 filter wheel grating spectroscopy. No conclusions yet, but I'd encourage others to conduct similar experiments about what might be detectable at which resolutions because this potentially opens us a whole new avenue for non-pro work on LPVs.
Keep in mind that LPVs present a challenge to pros because it can be hard to get telescope time to intensively study something for more than a few months. So if non-pros can contribute it opens a new dimension to study these stars.
Hi John,
I could also contribute if I would get a few stars to observe with my SA200 remotely. Presently I observe U Ori which is in maximum (or just past).
I could try as it is as mag 7 about in V.
Josch (HMB)
I may join your enterprise once I get my Spectra L-200 in May!
James
Thanks for that comment, John. I have been looking for a program, so I will try out some Miras at the Texas Star party this May. The initial program will be some that are approching maximum and others that are on the faint side, just to see if I can obtain useful data. If so, I will start following a few to see what happens. Not sure how faint I can reach with an Aply and a C11 at F7, but it should be fun.
Ed
I think we could detect changes in the depth of some absorption lines, from minimum to maximum, at least with an R=500 spectra taken with Alpy600. This means that spectra of LPV would be useful if the whole variation cycle could be covered (yes, magnitudes at minima make difficult to take useful spectra, but at least 'just before' or 'just after' should be ok).
Regards
Miguel