[vsnet-alert 5146] SY Vol bright outburst

[Taichi Kato <tkato>]

SY Vol bright outburst

    Rod Stubbings reports that the suspected dwarf nova SY Vol is probably
undergoing a bright outburst.

  YYYYMMDD(UT)   mag  observer
  20000723.492   142  (R. Stubbings)
  20000723.533   142  (R. Stubbings)
  20000724.514   140  (R. Stubbings)
  20000724.551   140  (R. Stubbings)
  20000724.585   140  (R. Stubbings)

    According to the GCVS, the minimum is fainter than 17.5.  The following
star seems to be the quiescent counterpart, which would make the outburst
amplitude larger than 6 mag.

USNO0150.05620695 085328.874 -711229.90 (2000.0) 21.9 22.2

    The object is also has a likely ROSAT detection [vsnet-chat 3133]

>    As pointed out by Greaves, the identification of SY Vol with the ROSAT
> source (looks secure) is very promising.  No observations have been reported
> to VSNET yet.

    Confirmatory observations, accurate outburst astrometry and multicolor
photometry, spectroscopy and time-resolved photometry are urgently needed.
Considering the large-amplitude of the outburst, the star may be an SU UMa
type dwarf nova undergoing a rare superoutburst.  The object is put on
the VSNET Collaboration target list.  See vsnet-campaign and vsnet-campaign-dn
for further detailed progress.

Regards,
Taichi Kato
VSNET Collaboration team

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