(cba:news) March stars, take one
jop at astro.columbia.edu
Thu Mar 6 05:42:06 EST 2008
This new optical transient in Hya (I think), from the Catalina Sky
Survey, has a good chance of being quite a gem! Below is ATEL 1411, the
discovery announcement, and Kato's comment. Since it is 17th mag now,
near the peak of outburst, it won't torment us for very long... but with
about a week of data we should be able to squeeze out a decent period.
Top - if transient! - priority for northern and southern observers.
Time to usher a few stars off the stage. V485 Cen, UMa 6, V436 Car, T
Pyx, DW Cnc... these stars are sufficiently well recorded for the year,
and can rest up for the off-season. I still have some hope for MU Cam,
but so far it doesn't seem to be too popular. HV Vir came down from its
superoutburst, and may now have some echoes; these are certainly
interesting but usually don't hump much (and they're hard to study
because the nightly light curves often have large slopes). So I'm
inclined, with reservation, to demote HV Vir also.
For northerners, it's a great time to get long runs on AM CVn. I'm just
wrapping a long-term period study. Such a study is maximally
constrained by the earliest (1978) and latest (now) data, so long time
series of this star are now - just for a few more weeks - would be great.
Has anyone been following OT1112-35? Since Greg Bolt's superb data of
December, I've been awfully curious about this star. Unfortunately we
can't reach this dec from Arizona, so I rely on australite CBAers to
tell me anything about it. It had a very long outburst, and I assume
has faded now. Has it? How bright is it? I'd really like to pursue
this guy any way possible!
I also recommend RX1039-05 = Sex. Finishing a long-term study on this
star also, and hence need 2008 timings. It's very faint (18) but has a
HUGE photometric modulation - try it, you'll be impressed with how faint
you can go when the wave amplitude really cooperates.
I'll write again later today. I'd love to hear any news about the new
Hydra (I think) transient.
CSS080304:090240+052500 is indeed a dwarf nova in outburst.
The presence of He II emission lines, as well as the large
outburst amplitude, suggest another WZ Sge-type outburst!
The splitting in the line profile would suggest a high inclination.
Title: Discovery of a Bright Optical Transient from the Catalina
Author: S.G. Djorgovski, A.J. Drake, R. Williams, A. Mahabal, M. Graham,
E. Glikman, C. Donalek (Caltech); J. Hennawi (UCB/LBL);
S.M. Larson (UAz/LPL); E. Christensen (Gemini Obs.)
Queries: george at astro.caltech.edu
Posted: 4 Mar 2008; 23:58 UT
Subjects: Optical, Request for Observations, Cataclysmic Variables,
We have detected a bright (V ~ 16 mag) optical transient in Catalina Sky
Survey (CSS) images obtained at the Mt. Bigelow 0.7m Catalina Schmidt
Telescope on 04 March 2008 UT.
<table border=1> <tr align=center><td><a
CSS080304:090240+052500</a></td><td> 2008-03-04 UT 05:34:11 </td><td>
RA 09:02:39.70 </td><td> Dec 05:25:01.0 </td><td> Mag 16.3</td></tr>
The transient is coincident within the astrometric uncertainties with
a marginally detected SDSS source (ID = 587732578836087360), which has
u = 23.76 +- 0.60
g = 23.17 +- 0.18
r = 23.10 +- 0.22
i = 23.00 +- 0.30
z = 22.19 +- 0.37
Thus, the source has brightened by about 7 magnitudes relative to the
The discovery data and the finding charts are posted at this webpage:
http://voeventnet.caltech.edu/feeds/ATEL/CSS The source was posted
in the real time at VOEvent pages,
A spectrum of the transient has been obtained with the ESI spectrograph
at the WMKO Keck-II 10m telescope on the same night, 04 March 2008 UT,
approximately 5 hours after the initial detection. It shows a blue
with emission lines of H-alpha 6563, H-beta 4861, He I 5015, He I 7065,
He II 4687, and He II 6683, with an approximate observed redshift of
150 km/s. The lines are bimodal, with a velocity splitting of about
We tentatively interpret this as a nova-like phenomenon. Further analysis
of the spectra is in progress.
More information about the cba-public