(cba:news) V713 Cep outburst; also VZ Scl, IM Eri (no go)
jop at astro.columbia.edu
Mon Nov 13 06:10:18 EST 2017
V713 Cep richly deserves observation. If in superoutburst, it's a GREAT
target. If in normal outburst, it's an excellent target. And even if
in quiescence, it's not too shabby either.
With our recent successes* re WZ Sge and ES Cet, I've come to realize
that we are in a great position to make some impactful studies of
orbital-period changes. For years I didn't think so, because with our
small scopes, our signal-to-noise is poor near the bottoms of typical
deep eclipses (typically mag 17-20), or typical shallow eclipses (just
0.2 mag deep). Now I realize: WRONG on both counts. Even with
40-second integrations, it's easy for us to get an accuracy ~5 seconds -
because integrative sampling is equivalent to instantaneous sampling,
and because we commonly get very large amounts of data (say 40 eclipses
Plus we're there year after year. Some of the present campaigns are in
part motivated by orbital-period issues (BT Mon**, X Cha, OY Car, U Gem).
Two stars to discontinue coverage: VZ Scl (excellent season, but we're
done) and IM Eri (analysis of last year's data suggests this star is
*Success here meaning completion of a paper reporting a many-year
campaign and its consequences. We have some smaller successes along the
way, of course.
**BT Mon is special, because its Porb = 0.3338 days. Thus its eclipses
drift by only 2 minutes per day. So space out your observations of this
guy. We want the full orbital light curve, not just the (very deep!)
eclipse. But it's NOT a star for the usual CBA style ("hit it every
night, in as dense a cluster as weather permits").
Beautiful planetary conjunction in tonight's morning sky!
-------- Forwarded Message --------
Subject: [vsnet-outburst 21482] V713 Cep outburst
Date: Mon, 13 Nov 2017 10:17:14 +0900
From: Taichi Kato <tkato at kusastro.kyoto-u.ac.jp>
To: suuma at yahoogroups.com, variable_star_forum at yahoogroups.com,
vsnet-alert at ooruri.kusastro.kyoto-u.ac.jp, vsnet-alert at yahoogroups.com,
vsnet-campaign-dn at ooruri.kusastro.kyoto-u.ac.jp,
vsnet-outburst at ooruri.kusastro.kyoto-u.ac.jp, vsnet-outburst at yahoogroups.com
V713 Cep outburst
Eclipsing dwarf nova below the period gap. No superoutburst
has been observed.
YYYYMMDD(UT) mag observer
20171030.521 <163c (Mitsutaka Hiraga)
20171108.516 <163c (Mitsutaka Hiraga)
20171112.794 158C (Jeremy Shears)
Center for Backyard Astrophysics (CBA) mailing lists
More information about the cba-public