SN 2002ao: Bright, Peculiar Supernova

The KAIT team discovered a brightest supernova SN 2002ao. IAUC 7809 informed that the discovery of SN 2002ao was made on Jan. 25 when a new object was mag about 14.3. The position is about 16" east and 10" north of the diffuse nucleus of the tilted open-spiral galaxy UGC 9299. The recession velocity of UGC 9299 is 1552 km/s (NED). If this velocity is of the Hubble flow, the expected maximum of a typical SN Ia is mag about 13.4 (vsnet-campaign-sn 326, 327). The object was brightening and reported to be 13.6mag on January 29 (vsnet-campaign-sn 336).

IAUC 7810 informed that a spectrum of SN 2002ao showed a blue continuum with broad features, which cannot be identified with Si, He, or H. They quoted the resemblance with type IIb SN 1996cb around maximum (vsnet-campaign-sn 334).  On the other hand, Kinugasa et al.(IAUC 7815) suggested that it can be of type Ic. The UCB group mentioned that it had very unusual spectrum; it had strong He I *emission* lines. Such emission lines are only observed in the nebular phase of type Ib SNe, which is very later phase. There was no sign of such profiles on Kinugasa's spectrum, so it must have experienced very rapid evolution (vsnet-campaign-sn 339, 345).

The fading rate of the object was relatively gradual until February 5 (vsnet-campaign-sn 346), and then, the object suddenly faded to 16.2mag on February 8 as reported by J. Nicolas. It was confirmed by Llapasset on February 13 at 16.3mag. Such rapid fading is very unusual for supernovae (vsnet-campaign-sn 348).

Other articles:
vsnet-campaign-sn 349, 351, 355, 360

Discovery image taken by P. Cacella:
[vsnet-campaign-sn 365]

General Information about This Object

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