Circular No. 6830

Central Bureau for Astronomical Telegrams INTERNATIONAL ASTRONOMICAL UNION Mailstop 18, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A. IAUSUBS@CFA.HARVARD.EDU or FAX 617-495-7231 (subscriptions) BMARSDEN@CFA.HARVARD.EDU or DGREEN@CFA.HARVARD.EDU (science) URL http://cfa-www.harvard.edu/iau/cbat.html Phone 617-495-7244/7440/7444 (for emergency use only)

SUPERNOVA 1998T IN IC 694

W.-d. Li, University of California at Berkeley (UCB), forwards the report from C. Li that Zhou Wan has found an apparent supernova (unfiltered CCD mag 15.4) on Mar. 3 UT as part of the Beijing Astronomical Observatory Supernova Survey. As with SN 1998S (cf. IAUC 6829), this object was confirmed by the Lick Supernova Survey at unfiltered mag about 14.5 on Mar. 4.3, with the corresponding KAIT position given as R.A. = 11h28m32s, Decl. = +58o33'.7 (equinox 2000.0); SN 1998T appears in a dust lane of the irregular host galaxy that has no apparent nucleus, so the relative offsets cannot be accurately determined, and its close proximity to a knot makes it difficult to measure (the magnitudes were derived from subtracted images). Observations of the same field prior to Mar. 3 do not show an object at the position of SN 1998T.

A. V. Filippenko and E. C. Moran, UCB, report that on Mar. 5 they obtained a Keck-2 spectrogram (range 510--900 nm, resolution 1 nm) of the stellar-looking knot on the southern side of the dust lane of IC 694 (the eastern part of the irregular galaxy Arp 299 = Markarian 171, of which the western part is NGC 3690; see Wynn-Williams et al. 1991, Ap.J. 377, 426). SN 1998T is indeed a supernova, of type Ib; strong P-Cyg profiles of He I lines are visible. Narrow nebular emission lines are very intense.

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