Abstract: Drs. Brandon Marshall (University of Nebraska) and Charles Kerton (Iowa State University) request AAVSO observers’ assistance in monitoring the unique variable ASASSN-V J022007.17+610705.5 (Cas) = VES 735 in support of spectroscopy observations being obtained at the Dominion Astrophysical Observatory in November and December.
This is a followup to Alert Notice 794, which provided photometry that was included in a recent publication to MNRAS: Long-Term Monitoring of the Oe Star VES 735: Ope! Not So Quiet After All.
I looked at the comp stars / check stars suggested by VSP ( sequence X38759AQG ), and checked if they are indeed constant by consulting Gaia DR3 Stellar Variability (vizier).
It appears that most of stars in the sequence are deemed variable, e.g., for 117 (000-BPL-393), Gaia results suggests the standard deviation in Gaia G photometry is ~0.0054 mag (instrumental variability excluded), or a range of ~0.0215 mag (an approximation by using 4X standard deviation).
Only 130 is constant (range of ~0.0021mag). 135 is marginal (range of ~0.0075 mag)
Should the sequence be redone? Or am I misinterpreting Gaia results?
For details, see this spreadsheet of cross matching the stars in the sequence with Gaia DR3 / Gaia DR3 Stellar Variability. The column SG in the spreadsheet / Vizier refers to the G band astrophysical standard deviation.
I checked the Gaia sources you mention in your spreadsheet (513499314883192576, 507480558176826752, 513443652107038464, 507494851818841856, 507494851828904704, 513487701291625728, 513502411559969792, 513498666348537600) and none of them appear in Gaia DR3 Part 4 Variability. In particular, I could not find any of them in I/358/varisum which is the summary catalog of variable stars in Gaia. In I/358/varisum we find max and min for variables in all 3 Gaia filters (G,B,R). The sources you mention do appear in I/358/gaiadr3. I assume that what we see in tI/358/gaiadr3 he catalog is instrumental uncertainty rather than variability.
Does this help? Am I understanding the issues correctly.
I’ve spent a lot of 2024 working on the Gaia catalogs with Sebastian Otero…so I’m slowly beginning to learn a bit.
I’d be happy to continue this conversation if that would help.
-leo
(leo.fernig@gmail.com)
None of them is in Gaia DR3 Variability, but I’m referring to Gaia DR3 Stellar Variability (VizieR, for the data and the link to the paper). The authors measured the variance in Gaia DR3 photometry, tried to separate out the astrophysical variation from instrumental variation. In the spreadsheet, the links in the column Stellar Var Flag point to the correspond records.