(cba:news) just Maxi = ASASSN-18ey... OK, also V1974 Cyg
jop at astro.columbia.edu
Wed Sep 4 10:22:23 EDT 2019
We're nearing the end of the time-series campaign on this star. We've
learned a few things.
(1) No matter how short you take your integrations, you see violent
variations. Quite unlike CVs, but seen in some black-hole X-ray novae
(where the variations extend down to milliseconds). So for our
purposes, there is no particular need or want for fast integrations
(since that information is basically in the X-ray).
(2) The huge 17-hour signal of last year is gone. There are some waves
suggesting a timescale around 10-20 hours. It's not yet clear if
there's a stable period (or two???) in there. And it may not ever be
clear, since the Earth's travels shorten our window at 4 minutes/day.
For these candidate timescales, changes in airmass are worrisome. But
it's likely our data are the world's best, so let's do our best and
leave honorably. Try to get these long time series for around another
(3) Tracking the decline from the August-September echo is a different
story. That's where "follow the star into a tree" is called for... but
very short time series (10 minutes) are OK. Ideally it should be V
(because it's a standard magnitude), but "clear" is OK too, especially
if you can estimate the difference. Remember - AS ALWAYS - avoid RED
comparison stars! (And, to the extent possible, keep the same one.)
David Cejudo has been faithfully tracking V1974 Cyg, but without a lot
of help. Too much razzamatazz over Maxie. That's "old" nova is
definitely a good target for observation - as is, in the morning sky,
the newly faded PX And.
p.s. the recurrent nova V3890 Sgr is also worth a peek. If it starts to
show fast variability, even more so.
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