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[vsnet-campaign-sn 102] SN 2000ds in NGC 2768
Dear SN watchers,
T. Puckett and his coleague has discovered a new faint SN in the
neighbouring galaxy in UMa. It seems to be of some atypical nature.
The location of the new object is: R.A. = 9h11m36s.24, Decl. =
+60o01'42".2 (2000.0), which is about 9" west and 32" south of the
center of the elliptical or lenticular galaxy (S0_1/2 in NED) NGC
2768. There is a mag 16 foreground star about 1' WNW of the nucleus.
The reported magnitudes are: Oct. 10.40, 17.9C; Oct. 12.34, 18.1C.
Previous images on 2000 May 28 did not show SN 2000ds.
Such an early type galaxy as NGC 2768 are thought to produce only
SNeIa because the massive stars has not been born in (astronomically)
recent years. The recession velocity of NGC 2768 is 1373 km/s, so the
expected maximum of typical SNeIa is about mag 13. Almost the same
brightness in 2 days suggest that it is not a young (10+ days before
maximum) SN Ia. And, typical SNeIa 140 days after maximum is about
3-4 mag dimmer than at maximum. Taking them all into account, SN
2000ds could be a old SN Ia affected some extinction, or be of
somewhat dim nature. The other possibilities, however, has not been
excluded such as it is in the rising phase. The spectroscopic
observation is needed for further discussion, and the follow-up
magnitude estimates are also useful. Needless to say, the check on
the pre-discovery image is quite recommended.
Sincerely Yours,
Hitoshi Yamaoka, Kyushu Univ., Japan
yamaoka@rc.kyushu-u.ac.jp
vsnet-adm@kusastro.kyoto-u.ac.jp
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