[vsnet-alert 1859] (fwd) Finding V2051 Oph's Friends

[Taichi Kato <tkato>]

Date: Thu, 4 Jun 1998 15:25:39 -0400 (EDT)
From: Joe Patterson <jop@astro.columbia.edu>
Subject: [vsnet-obs 12452] Finding V2051 Oph's Friends




                 V2051 OPH: JOINING THE SU UMA CLUB?

     We have been studying the nightly time series of V2051 Oph for its
last 13 nights of outburst.  In addition to the deep eclipses occurring
regularly every 0.062428 days, the star is flashing large-amplitude
photometric waves at a slightly different period.  In early outburst
(JD 955-957), the star displayed 0.35 mag waves at a period of
0.0640+-0.0002 d.  The amount of period excess (2.5%), the amplitude,
and the waveform (fast rise, slow decline) are all thoroughly normal
for an SU Ursae Majoris-type dwarf nova.  A few irregular dips occurred
too, as often seen in the edge-on members of this class (Z Cha, OY Car,
WZ Sge).

     With such credentials, it seems quite reasonable to use the term
"superhumps" to describe these waves.

     Since JD 960, the variations have become more complicated.  The
superhumps continue, but are accompanied by orbital variations of about
the same amplitude, resulting in "beats" as the incommensurate signals
drift in and out of phase.  The irregular dips also continue.

     V2051 Oph remains a great target for continued close scrutiny!
We'd love to hear from others who may have obtained, or could obtain,
coverage of the star.  And it would be awfully interesting to know if
the outburst history suggested a long/short dichotomy, as normally (but
arguably) required for full membership in the SU UMa club.



Joe Patterson   Dave Harvey   John Stull    Lasse Jensen*  Greg Bolt
Jonathan Kemp   (CBA-Tucson)  (CBA-Alfred)  (CBA-Denmark)  (CBA-Perth)
Raefer Gabriel
(CBA-New York)


*By the way, it's worth noting that Lasse's light curve (posted at the
VSNET site) of this star at Dec=-26 degrees was obtained with a 10-inch
telescope at +56 degrees latitude, with white nights (no darkness).
He tells me that he has "recently moved to a better site".  I guess
we can all agree with that.

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