A call to arms: extragalactic variable star observation.

[Xilman]

This thread arises from Mr Spock's generous encouragement in

 

Although there are many thousands of variables in the Milky Way which are observed by amateurs and many useful measurements are reported to the likes of the BAA-VSS and AAVSO, very few people monitor variables in other galaxies. I find this rather disappointing.

Amateurs way down south have it easy. Both the LMC and SMC are close enough that a good number of VS are within range of binoculars or small telescopes.

Those of us further north are a little more constrained. Either we use robotic telescopes and/or we look at local group galaxies which rise above our horizon. Note that I am explicitly avoiding supernovae, despite their extremely valuable coverage by the likes of us. The obvious galaxies are M31 in Andromeda and M33 in Triangulum.

I must be honest: visual observers will need large apertures, dark skies, and will be limited to only a few targets.  That said, I have made visual estimates of both AE And and AF And in M31 with a 46cm Dobsonian.

At least one kind of variable, those catalogued as SDOR and are also known as LBVs --- luminous blue variables --- are actually easier to observe outside the MW in some ways. For a start there are more of them and they tend to vary in brightness rather more than the nearby examples.

If you have a camera and at least 20cm aperture there are hundreds, if not dozens,  of  extragalactic variable stars which are within your capabilities and, because they are not monitored as frequently as desirable, are within your ability to conduct genuine scientific research. Even if you don't want to be at the bleeding edge, you could confirm the period-magnitude relationship of Cepheids and so make your own measurement of the distance to M31 and M33.

If anyone would like a challenge, I can very easily provide more help and information .

 

OBTW, and in line with the double star focus of this sub-forum, I may have discovered an eclipsing binary in M31. More analysis is needed decide whether it is real or not.

 

 

 

 

Edited November 19, 2021 by Xilman

[Mr Spock]

2 minutes ago, Xilman said:

I may have discovered an eclipsing binary in M31. More analysis is needed decide whether it is real or not.

If you have, that's very exciting. I look forward to hearing about it.