[vsnet-newvar 2625] OT_J021110.2+171624 (new SU UMa-type dwarf nova)

[Taichi Kato]

   Forwarded messages from cvnet:

===

From: Patrick Wils 
Subject: [cvnet-discussion] Possible dwarf nova

The Catalina Sky Survey <http://voeventnet.org/feeds/Catalina.shtml> has
observed an optical transient of magnitude 14.3 last night
<http://nesssi.cacr.caltech.edu/catalina/20080130/801301180124103586.html>
which might be an outburst of USNO-B1.0 1072-0031053 (position 02:11:10.19
+17:16:24.4), a star which is normally R=19.2. Brightenings are not seen
on NEAT images <http://skyview.gsfc.nasa.gov/skymorph/skymorph.html>, but
the object appears bright on 2 out of 9 POSSII images (a blue image from
1987.94 and a red image from 1990.88, while it was faint on red images 1
and 2 months before). These images are available for a limited time at
<http://www.nofs.navy.mil/tmp/fchqDBQy8_fch.html>.

Patrick

===

From: Tonny Vanmunster <tonny.vanmunster at gmail.com>

Dear colleagues,
 
There's definitely a new object at the below reported position. I just
collected a few CCD images (Jan 30.83 UT) and the optical transient is
visible at mag 14.2 (unfiltered). 
 
Sky conditions are not too bad, so I have started a CCD photometry session
on this target using a 0.35-m f/6.3 telescope and ST-7 XME CCD. I hope to
continue for another hour or two. Hopefully someone else can take over later
tonight in the US.

 
I'll keep you posted on my findings.
 
Best regards,
Tonny
 
PS : Thank you Patrick, for reporting this outburst !
Tonny Vanmunster
CBA Belgium Observatory
http://www.cbabelgium.com <http://www.cbabelgium.com/> 

PERANSO : The Light Curve and Period Analysis Software
http://www.peranso.com <http://www.peranso.com/> 

===

From: "Tonny Vanmunster" <Tonny.Vanmunster at cbabelgium.com>
Subject: [cvnet-outburst] Optical transient OT_J021110.2+171624 is most likely a new UGSU-type dwarf nova

Dear colleagues,

Earlier today, Patrick Wils announced (on cvnet-discussion) the detection by
the Catalina Sky Survey of an optical transient (mag 14.3) on Jan 29th, that
was suspected to be an outburst of USNO-B1.0 1072-0031053 (position RA =
02:11:10.19, Decl = +17:16:24.4, J2000.0), a star which is normally R=19.2.
Patrick furthermore reported that object appeared bright on 2 out of 9
POSSII images.

Following Patrick's announcement, I started unfiltered CCD time-series
observations of the new OT at CBA Belgium Observatory on Jan 30.833 UT,
2008, using a 0.35-m f/6.3 telescope and ST-7XME CCD camera. Sky conditions
were good, and the session lasted for 2 hours. The resulting light curve is
presented at my website (www.cbabelgium.com) and shows a superhump-like
structure with an amplitude of 0.15 mag. Given the short duration of the
session, it's difficult to accurately establish the hump period. Using
Peranso's implementation of the ANOVA method, I find a value of 0.063 +/-
0.009 d. The ANOVA period window and phase diagram for P = 0.063d are
presented as well.

Follow-up CCD and spectroscopic observations are highly needed to further
study the lightcurve characteristics of this dwarf nova and to firmly secure
its UGSU nature.   

Tonny Vanmunster
CBA Belgium Observatory
http://www.cbabelgium.com 
 
PERANSO : The Light Curve and Period Analysis Software
http://www.peranso.com