(cba:news) July stars
jop at astro.columbia.edu
Tue Jul 9 06:50:03 EDT 2013
New stars for the new season.
It's time to end the HS1813+61 coverage. The star has wandered between
a high-ish and a low-ish luminosity state, and the periodic content has
been complicated by that feature. Definitely for analysis in the cold
light of winter... and time to end 2013 coverage.
And time to replace this "Dra" star by a new kid in Draco: ASASSN-13ax,
discovered in a supernova search (and therefore using the supernova
lingo as an identifier). In our familiar language, which Taichi Kato
likes/promotes and which is well suited to our objects, it would be
OTJ180005.78+525635.3. Sitting up there in Draco, perfectly positioned
for summer coverage. Enrique has been observing it for a few days, and
last night it grew the strong superhumps which are the
always-good-for-admission ticket to our club. In particular, it's very
likely a WZ Sge star, erupting from mag 21 to 13.5, with some unknown
but probably long recurrence period. It's still at mag 14 and will
probably flash great superhumps for a couple more weeks. Probably.
Anyway, it's a superb target for long runs.
We're getting ready to publish our decade-long (but somewhat sporadic)
coverage of V1974 Cyg and V1432 Aql, and both stars need a final fix of
2013 data. These two require pretty long coverage, in order to parse
among the (known or putative) signals closely spaced in frequency. One
month of dense data would bring these campaigns to an end.
And the big star in the June CBA world has been PNV1915+07, which has
been getting great coverage by practically all of our usual suspects -
especially Enrique, Jim Jones, and Greg Bolt. This WZ Sge star, now
faded to 16.3, continues to delight with its big periodic wave. Since
the 2013 outburst is the first-ever-recorded, and indeed the first time
the star publicly announced its existence, we don't know what the future
will bring. Let's make sure our telescopes are there to find out!
The DQ Her stars (intermediate polars) can take a rest in mid-summer,
i.e. now. The two exceptions are V1223 Sgr and IGR1654-19 (Scaringi et
al. 2011, A&A 530, A6); each needs a few nights to tie down the
long-term cycle count.
Finally, don't forget NR TrA and V617 Sgr! These stars have great light
curves and need your help. The first is the known remnant of Nova TrA
2008, while the second is a suspected (OK, only by me... but still)
remnant of a recent but unnoticed nova event.
We're very likely to have a AAVSO+CBA meeting in mid-June 2014, and I
especially hope that some of our seldom-seen members can attend. It'll
be at Big Bear, or possibly some other southwestern USA location. More
info when the details harden up.
More information about the cba-public