CBA Center for Backyard Astrophysics



CBA Message

Tonny's 1-Cycle Dwarf Nova
(31 January 2008)

Dear CBAers,

Please take note of this guy.  The light curve definitely suggests a 
superhump, but the sky position is so awkward that the period will be 
very tough to nail unless we can get round-the-world coverage.  If you 
have a clear evening sky, see if you can squeeze out a short time-series 
(the longer the better, of course).

Borealites only, of course.  By the way, on the other side of the night, 
it's AM CVn season again.  I've written a short paper on the orbital 
period change in AM CVn; all it needs is one more seasonal timing in 
February 2008, and it's complete.  That would be YOUR timing!

Happy observing!  I'm sure I don't need to tell you, but there's a 
beautiful conjunction of Venus and Jupiter in the predawn sky this week. 
Gorgeous sight even from the Big Apple.

joe

-------- Original Message --------
Subject: 	[cvnet-outburst] Optical transient OT_J021110.2+171624 is most
likely a new UGSU-type dwarf nova
Date: 	Thu, 31 Jan 2008 00:29:12 +0100
From: 	Tonny Vanmunster <Tonny.Vanmunster .at. cbabelgium.com>
Reply-To: 	cvnet-outburst .at. yahoogroups.com
Organization: 	CBA
To: 	<aavso-photometry .at. mira.aavso.org>,
<cvnet-discussion .at. yahoogroups.com>, "'CVnet outburst'"
<cvnet-outburst .at. yahoogroups.com>
CC: 	Cba-Chat <cba-chat .at. cba.phys.columbia.edu>, cba-news
<cba-news .at. cba.phys.columbia.edu>

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