The 1998 April TRUE outburst (click here!)

Preivous issues:

LY Hya = 1329-294: NO OUTBURST, but object deserves monitoring

Tonny Vanmunster relays in his CVC 79 (also vsnet-obs 2047) that LY Hya is being observed in outburst at V~14.4 by Steve Howell, who is performing infrared spectroscopy of CVs at Mauna Kea. Although this object has been suspected to be a dwarf nova, this is probably the first-ever recorded outburst. Further observations are emergently needed.

LY Hya, also called 1329-294, was originally discovered as a faint blue object near the famous spiral galaxy M83. This object soon turned to be a cataclysmic variable. Echevarria et al. 1983 (MNEAS 205, 559) obtained spectra which showed doubly peaked emission lines of Balmer and HeI, suggesting a high-inclination system.

Haefner et al. 1993 (Astrophys. and Space Sci. 204, 199) performed a radial velocity study, reporting the most probable orbital period of 0.13688 day. Their spectra showed very strong Balmer and HeI emission lines, whose equivalent widths suggest a dwarf nova with a low mass-transfer rate, rather than a nova-like system as initially thought.

More recent observations by Still et al. 1994 (NNRAS 267, 957) favored a solution of the system below the period gap. All these observations suggest that the object has been observed in quiescence, and that we may expect dwarf nova outbursts. Altough it is not still clear whether the present reported outburst is a normal or a super- outburst, the observations by Howell seem to verify its suggested classification.

    133153.93  -294059.9    2000 LY Hya     UGSU:         (?)-17.4-18.4V

NO CURRENT OUTBURST - Howell's message

(from vsnet-alert 320)

This note is to infoirm the vsnet observers that the sespected outburst of LY Hya was an error. The star is listed in various places with some giving a magnitude limit of 14-18 and others (which are more easily obtained such as the downes and shara catalogue), list it simply as 17-18. The error occured when I asked via email to the Belgium Variable Star Group, simply for information they might have on any actual outburst ever seen for this star. That message was then confused as a message stating that LY Hya was currently in outburst.


This star is a suspected SU UMa star and it should however be monitored for any outbursts which may occur in the future.

Dr. Steve Howell (UKIRT- Mauna Kea)

VSNET charts of LY Hya

Enlarged chart


Information is also available on Vanmunster's CV Home Page.

Taichi Kato

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