SV Vul

[quote=BBI]

Is it actually "usefull" to observe this type of variable? Does the lightcurve change over the course of years? Or are people observing it just for the fun of it?

[/quote]

There have been discussions in the past regarding what stars are "useful" to observe. To a degree, it depends on who is studying what at any given time. Certainly, classical Cepheids, being one of the core "standard candles" in the universe, are quite critical to cosmology, distance scales, and other active areas of study. While their properties are very well known and pretty stable, they are so important to critical questions of the universe, that any new information uncovered could have a significant impact. For example, the recent discovery of two subtypes of the Type-1a supernovae, can make a big impact on current models such as lambda-CDM!

So, I think long-term coverage of Cepheids is a worthy and useful endeavor. Just like long term monitoring of LPV's, a core effort of AAVSO since its inception, has uncovered important discoveries about period changes.

Mike

I seem to recall that SV is in the same field as some more 'interesting' variables. Maybe some people are estimating them 'as a bunch' rather like I always do RR, CQ and AD Tau together.

Indeed, they change and these changes are important. The very SV Vul is featured in the paper "Enhancing Our Knowledge of Northern Cepheids through Photometric Monitoring" by David G. Turner et al., which states "the study of Cepheid period changes can yield vital information on the location of individual variables within the Cepheid instability strip".

You can find interesting the JAAVSO published survey Classical Cepheids After 228 Years of Study by the aforementioned Turner.