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Special Notice #87: New WZ Sge variable in Hya [VSX J111217.4-353828]

January 5, 2008: VSNET announced the discovery of an optical transient by Marcin Sokolowski of the "Pi of the Sky" group (alert 9764, 12/21/2007). Precise coordinates were obtained at SRO (vsnet-alert 9772) and elsewhere:

11:12:17.40   -35:38:28.8    J2000

(SRO, UCAC2, errors less than 100mas)

A match was made by Brian Skiff (vsnet-alert 9769) with a faint blue GSC2.3 star at

11 12 17.44 -35 38 30.1 J2000

with an arcsec coordinate error. At R=20.88 and proper motion over several decades, the match is consistent. This gives an amplitude of about 8-9 magnitudes, about right for a WZ Sge cataclysmic variable.

Hiroyuki Maehara (vsnet-alert 9778) analyzed images from Greg Bolt, and found early superhumps with a period of about 0.05843d.

As reported by Daisaku Nogami (vsnet-alert 9782), Kenzo Kinugasa has obtained optical spectra at GAO that indicate this is a typical dwarf nova outburst with Halpha and HeI emission lines.

This object is now listed in VSX as VSX J111217.4-353828 and can be plotted from VSP using that identifier.

A BVRI field calibration can be found at: and a sequence extracted from this will be available shortly.

Last reports from SRO give the magnitude as V=13.8 and remaining very blue, with no strong Halpha signal in the Rc filter. We expect this object to start fading shortly, and ask observers to monitor it nightly, increasing your observing cadence if you see it fade.

Arne Henden


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