Affiliation
American Association of Variable Star Observers (AAVSO)
Sat, 05/02/2015 - 19:22
In the AAVSO has a star that had not been observed. For instance I found that the star has not been observed since 1969. How useful / necessary to carry out its observation?
Nikolay
[quote=mishnik]
In the AAVSO has a star that had not been observed. For instance I found that the star has not been observed since 1969. How useful / necessary to carry out its observation?
[/quote]
Hi Nikolay, It would depend on the star! Some stars have been determined to be constant, others are very normal LPV or CV, maybe very faint, so nobody follows them. Such stars may be useful to followup! So, it really depends on the star. Check VSX first and see what its "type" is.
Mike
For example V0413 Lyr. I checked in there VSX no specific data. For variable star 50 years is a lot. I think so.
Nikolay
VSX tells us it is an EA/SD type, basically an eclipsing binary, nothing much else particular about it. Hitting the "?" after the type gives you:
EA
β Persei-type (Algol) eclipsing systems. Binaries with spherical or slightly ellipsoidal components. It is possible to specify, for their light curves, the moments of the beginning and end of the eclipses. Between eclipses the light remains almost constant or varies insignificantly because of reflection effects, slight ellipsoidality of the components, or physical variations. Secondary minima may be absent. An extremely wide range of periods is observed, from 0.2 to ≥10000 days. Light amplitudes are also quite different and may reach several magnitudes.
SD
Semi-detached systems in which the surface of the less massive component is close to its inner Roche lobe.
And, there is a reference given for more information too - http://articles.adsabs.harvard.edu/cgi-bin/nph-iarticle_query?1971PZ…
Which is even in Russian :) So, you can judge for yourself if this star is in need of further observations? It looks like it is no more than a usual eclipsing star, and once its period and amplitude is determined, there is not a lot of new information to be got by further prolonged observation, but maybe somebody is interested in such stars, for long term too?
Mike
I saw this article. And I understand that it is a type. The question is how useful observations of stars that have been observed for almost 50 years? Even the phase curve of the star there.
Nikolay.
This star has probably not been studied since Kurochkin's "discovery" paper. The problem is, it is so faint (mag 14.5 at maximum, according to VSX). The BRNO O-C Gateway site does not list any eclipse time-of-minimum observations (see the AAVSO EB Section pages for reference and link). As LMK said, it is probably a very average 3 day eclipser, but who knows? I have been following some similar stars for many years, accumulating data on their period change behavior. V413 Lyr might be a very interesting star, but it is more likely to be "average". It is not likely to get much (or any) attention unless someone shows it is special. At this point, because there are NO times of minima for the past 50 years, we have no idea whether it shows period change behavior, or any intrinisic variability. If you observe it, you are likely to be the only one, because it is faint, unless you discover that it is very interesting for some reason.
Gary Billings
Some additions:
V0413 Lyr is EA binary with a period of 3.146774 days. To cover all curve phenomena as primary and secondary minima you will need very long time of observations. See the screenshot to see how rare you will get suitable nights to catch the minima. Most of the phenomena will happen during the day. You have to do whole night time series CCD imaging to cover the entire light curve (LC). To accumulate data on its period change behavior you have to do this for many years from now and to be very, very dogged
As Gary Billings said in the previous post “V413 Lyr might be a very interesting star, but it is more likely to be "average". To judge this as a single observer will be very hard job and probably this is the reason that nobody follows that star.
Velimir
I still try and observe the phase curve to get. Also I like eclipsing star.
Nikolay.
All the same, included in the program of observations.
Nikolay