I did my first measurements of Ry Tau tonight but I noticed that the star is surrounded by a faint nebula and I'm wondering how this affects the measurements. With my sampling (1.44"/pixel), the nebula is entirely contained inside the second circle during photometry, so hopefully it does not impact the measurements too much. Still, I would love to have advice from experts on how to handle this specific case of variable star inside a nebula.
Thank you,
jf
Hi,
It is the first time I am trying to do photometry on Young Stellar Objects and I am not sure if I am doing the right things. I am currently following RR Tau with both V and R filters and I am wondering if the star 130 or the 118 in the RR Tau AAVSO star chart (30' FOV) are a good choice as comparison star.
Would it be possible to get an advise on the above choice or a suggestion for a better comparison star?
Thank you in advance
Marco
Both of these…
Hi Marco,
Both of these stars are, I am sure, good for RR Tau. Neither have excessive B-V values (so are unlikely to be variable themselves!) but I checked the ASASSN database just in case. With two separate detectors neither star shows discernible variability outside error margins. So basically they are as good comp stars as you will find!
Good luck with your obs.
Michael Poxon, YSO section leader, Norwich, UK
Thank you for…
Hi Michael,
Thank you for your reply and advise. I started to analyse the collected data using the 118 as reference star and 130 as check star and they seem working fine. Bad weather and full moon close to the star did not help, however I have been able to collect few overnight time serie with S/N >30 (as requested). From a preliminary analysis, the nights of the 21-22-23 Nov, the star showed a first descending from 12.65 Vmag to 13.75 Vmag and then a little ascent to 13.50. Then the night of the 25 Nov once again a descent to Vmag < 13.8. I am missing the night of the 24 Nov. I wish to show the time serie just to have a confirmation the data analysis is OK but I dont know how to upload the graph.
Thanks again for your help.
Marco
Looking at the RY Tau light curve the past week or two (JD 2460266-2460275) it seems to me there are indications of an oscillation with a period of 3-4 days and an amplitude of around 0.2 magnitudes. Assuming the signal is real, I wonder if this could be due to axial rotation and features such as hot spots on the stellar surface?
I recently read an article on RY Tau in MNRAS (P.P. Petrov et al. 2021) where it seems their long term monitoring of the star between 2013 and 2019 could not with confidence detect an axial rotation period. However, based on the stellar parameters they estimated the period to be about 3 days.
It would be exciting if the AAVSO light curve could confirm the axial rotation period. Looking at the historic light curve it seems RY Tau is currently at its brightest for more than a decade, and one could speculate that this indicates the star is unusually unobscured by gas and dust, thereby allowing the brightness modulation caused by axial rotation to come through.
AAVSO Alert Notice 843 announces a new observing campaign beginning immediately on five YSOs - R Mon, UX Ori, CO Ori, RR Tau, and RY Tau. Please see the notice for details and observing instructions.
There are threads for this campaign under the following AAVSO forums:
- Campaigns and Observation Reports: https://www.aavso.org/5-ysos-2023-campaign
- Young Stellar Objects: https://www.aavso.org/5-ysos-2023-campaign-01
Please subscribe to these threads if you are participating in the campaign so you can be updated. Join in the discussion or ask questions there!
Many thanks, and Good observing,
Elizabeth O. Waagen, AAVSO HQ