I've been collecting and submitting data on this star since late February 2021. I thought its intense red color and rapid deep fades of 3 - 4 mag in V as suggestive of a YSO. Sadly, I only have BVRI data for one night, all remaining data is V only.
Mike Poxon examined the data today and seems to concur.
"Well, the depth and rapidity of the fades certainly make a good case, as does the J-K (1.7) Unfortunately VSX doesn't give a B-V to compare it with but it's a fair assumption that the B-V will be less than the J-K, thus more strongly suggestive of a YSO. However on the DSS colour image it appears to be quite red - but also it is the S member of a pair separated by only 6" so may present problems observationally.
I have been doing a bit of research on this one, and there is an 18th-mag object in Pan-starrs that differs by 6" in RA from the original MISAO discovery, which is the correct one. Using the original position from Panstarrs shows no star at that position so I think it safe to assume that the star in the DSS image is MIS V0980 - and it is clearly brighter than 18th mag. The B-V is 1.013 therefore with B-V < J-K it does look as if we have a YSO!"
But there is a paucity of observations and virtually all from one person (me) and one system (AAVSONet SRO).
I encourage others to add to the dataset!
RA 18 58 55.40 Dec +22 29 54.4 in VUL. V range: 14 to below 18 mag.
The ASAS-3 lightcurve shows variation between 13.5-14.5 with what appear to be numerous <15 results, but unfortunately the scale of these plots are too small to show further detail. The star, despite being reasonably red on DSS images (which I know is not a cut-and dried affair) is not in 2MASS, though the error ellipses could include it. Its B-V of 1.013 was determined by running the parameters from Panstarrs through the sequence team's spreadsheet, as no values are given elsewhere. It indicates a spectrum of K, thus suggesting that IF it is a YSO - which is by no means yet established - it is probably a T Tau; however the rapidity and depth of Peter's observations suggest that if it is, its behaviour is hardly typical T Tau fare! Similar activity has however been reported recently on other TTs such as SU and RW Aur.
I have saved…
I have saved the stacked images I analyzed, but not the unstacked. If anyone is interested in checking my work, I'd gladly share them. And I'll begin saving unstacked images as well!
Disclaimer: I only took the VPhot class last year and only have been submitting data since 10/2020, so there is a chance, hopefully small, that I've messed up the analysis!
OK, looks as if this star is a faint Mira. Earlier obs strongly suggest that the close companion contributed to the post-discovery results. Having no B-V for the object meant I had to resort to indirect methods to calculate it, and which turned out too low. Alert over!