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Special Notice #94: Possible CV in Hya [V498 Hya]

January 22, 2008: Taichi Kato drew attention in vsnet-alert 9834 to another starĀ  [V498 Hya] on the CBAT unconfirmed observations page:

2008 01 19.592 08 45 55.08 +03 39 29.7 13.3

Hiroyuki Maehara in vsnet-alert 9847 indicated that his observations of the star did not show any sign of ordinary superhumps, but did show small amplitude (~0.1mag) modulations.

Martin Nicholson also imaged the object using a robotic observatory in New Mexico, getting 2454485.83625 13.46V and 2454485.83435 13.48B.

This confirms the outburst and the blue color, indicating that it is probably a cataclysmic variable in outburst.

The position matches the following USNO-B source:

USNO-B1.0 0936-0175941 08 45 55.08 +03 39 29.3 B1 20.99 B2 19.74

and with the SDSS object

08 45 55.07 +03 39 29.3 J084555.07+033929.2

20.579 20.587 20.587 20.849 20.988 (ugriz)

obviously indicating that the progenitor was also blue, and that the outburst amplitude is about 7 magnitudes.

This is likely another WZ Sge subclass star, and is a good candidate for monitoring until it fades from this outburst.

We will get it added to VSX and VSP/AID as soon as possible.

Arne Henden

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