SN 2001B : Bright type Ib supernova reaching 14th mag

SN 2001B was discovered by Beijing team on January 3.61 UT (mag about 15.5) and confirmed on the next day with 0.3 mag brightening. The position is about 6" west and 9" south of the nucleus of the somewhat odd-shaped face-on spiral galaxy IC 391. It lies on the midpoint of the southern diffuse arm. The recession velocity of the host galaxy (1556 km/s) suggests that the typical SN Ia without extinction is mag about 13.3 at its maximum (vsnet-campaign-sn 126). It reached the peak at around 14.4mag (vsnet-campaign-sn 134). The object was revealed as of type Ib, not Ia as reported earlier. Jan. 23 spectrum tells that it was about 1 week past maximum, which is coincident with vsnet-reported observations (max around mag 14.5 at Jan 15). Generally, SN Ib has a maximum 1 magnitude dimmer than normal SN Ia. As the expected maximum for SN Ia was 13.3, the vsnet light curve shows very good agreement with it (vsnet-campaign-sn 149).

CCD image presented by T. Vince

Other related articles: vsnet-campaign-sn 128, 127, 129, 130, 136, 151

CCD image presented by K. Kadora: