I would like to draw attention to the star NSV 1161, which I think is an exciting star that there doesn’t seem to be much research on.
It is a young star in the nebula NGC 1333 with a very complex light curve. It has a periodic part of 2.1 days with an amplitude of about 1.5 magnitudes, in addition to a seemingly random variation of another 2 magnitudes.
According to the Russian scientist Vladimir Grinin, with whom we at SAAF have been in contact, NSV 1161 is probably an AA Tau star with an unusually large amplitude.
AA Tau is a subtype of T Tauri stars with a complicated interaction between the star’s magnetosphere and the inner disk region and the angle of view from which we observe the star.
I am currently observing the star via AAVSONet with 1-2 observations per week, but time series would probably also be interesting to get a more complete picture of its behavior.
Many thanks for that Thomas, it looks like a good object to follow, especially with reference to the ‘random’ variations. Grinin is of course a ‘first-magnitude star’ in YSO studies so I would take seriously his conclusions. Maybe a time-series study of one or two of those 2.1 day cycles, which look like rotational modulations? If this is so then it ties in with extreme youth; for comparison, AA Tau shows an 8-day cycle.
Also it would be good to get data in at least B at 3 or 4 stages of a cycle to see any contributions from the circumstellar environment. This is one for the next issue of the YSO newsletter (to which you are welcome to subscribe)
Thanks Michael, subscription mailed. I’m only a casual observer and have no deeper astrophysical knowledge, but I think this star could be of intrest for deeper studies.
In SAAF we have followed the star for two years after its variation was discovered serendipitously by Petter Åström when he blinked the DSO-images he took on NGC 1333. His resulting image can be seen here. We have done a few timeseries, but the star is difficult as you only can get a part of a cycle during one night and the cycles does not repeat exactly so that you can combine data from several nights to get a complete lightcurve.
Herbig mentions the object in a 1972 paper in the Ap J, where it appears as no.271 in the Lick Catalogue of H-alpha objects. He does not mention variability, only that it is a young star in the NGC1333 association. Maybe we can run a campaign on the star, so I shall have a word with HQ about it.
To clear up any misunderstandings, Petter saw a star that varied in his images, and we identified it as NSV 1161. So it was an already known variable, but it was new to him and the rest of us at SAAF. There wasn’t much information about the star and it seemed to vary quite a lot and quickly, so we became curious to observe it more.
