Affiliation
American Association of Variable Star Observers (AAVSO)
Mon, 03/04/2013 - 22:25
I extracted some 340 star names from the most recent CVNET Circular. Forgive my ignorance (and please help it) but what are these stars? I know they are CV's but are they the only ones known, are they the only ones of interest (to someone), are they somehow "recommended" for study? What? Why do they get this attention?
Jim Roe [ROE]
Hi Jim:
I'm not sure this is really what you are looking for but I'll just run through a few basics.
Probably the best place to go is the CV section site at
https://sites.google.com/site/aavsocvsection/
Basically CVs are binaries in which a white dwarf is cannibalizeng gases from a companion. These gases impinge on an accretion disk arround the white dwarf and periodically exhibit outburst behavior (brightening of the system believed to originate in the disk itself rather than the surface of the star).
There's a whole zoo of variations on a theme from those with a classical accretion disk to those whose magnetic fields are strong enough to prevent formation of the disk to the Z Cams which seem to get stuck in between minimum and max etc.
The ones on the circular are not the only ones known by any stretch of the imagination but those which generate the most interest- i.e. have long histories of observations, exhibit odd behavior, or are suspect or simply need more observations. The Z Cam campaign identified some which turned out not to be Z Cam types and others that were suspected but not definitely known to be Z Cams. These are very fascinating stars to study and are believed to be the precursers to novae, re-current novae, Type Ia Supernovae, etc.
Hi Jim
The stars in the circular are the ones for which obsrvations have been received by us observers. If no-one observes a particular star for that period, eg something that sets close to sunset, then it is not listed in the circular.
I try to observe all CVs (UGs + a few others) whose maximum brightness is about 14.5V and south of Dec +10° (I live in the Southern Hemisphere), and obviously for which sequences exist. You can use VSX to help you identify these.
You need to select stars that you can see at maximum. So it is pointless me trying to observe something that only reaches 16.0 in my 12"
Best wishes with your observing
Stephen [HSP]
Thanks for the info. I am curious as to what, and why, folks are observing. I have some room in my target list for a few more stars, plus I'm thinking to bring another telescope online which would add more capacity.
Jim Roe [ROE]