2010CBET.2479....2S

S. J. Smartt and S. Valenti, Queen's University, Belfast; S. Mattila, E. Kankare, S. Katajainen, and S. A. Bird, Tuorla Observatory; and T. Pursimo, Nordic Optical Telescope, report that they obtained low-resolution spectra (range 320-910 nm) of 2010ik on Oct. 3.95 UT with the Nordic Optical Telescope (+ ALFOSC). The spectrum suggests that 2010ik is a type-Ib/c supernova at approximately 1-2 weeks after maximum light; however, some peculiarities exist. Comparison of the spectrum of 2010ik with a library of supernova spectra using the "GELATO" code (Harutyunyan et al. 2008, A.Ap. 488, 383) yields a good match with the type-Ib/IIb supernova 2008bo (Navasardyan et al. 2008, CBET 1325) and with the peculiar type-Ib supernova 2005bf (Anupama et al. 2005, Ap.J. 631, 125), but with a redshift of z = 0.025, which is much higher than the redshift of the likely host, UGC 112 (z = 0.016, from NED). Fixing the redshift at z = 0.016, there is also a reasonable match with the spectrum of the type-IIb supernova 2008ax (Pastorello et al. 2008, MNRAS 389, 955) at seven days after maximum. The authors further report that an image from the NOT provided magnitude R about 18.7 for 2010ik on the same date (Oct. 3), and (assuming a Hubble Flow distance to UGC 112 of 70 Mpc) this suggests an absolute magnitude of -15.7 (after correction for foreground extinction of A_R about 0.19, from NED). If there is no further internal extinction from the host galaxy, this is faint for a type-Ib/c or type-IIb supernova. Furthermore, the measured magnitudes of Grennan, Boles, and Arbour suggest that 2010ik has had a "plateau-type" phase for around two weeks, which is again unusual for a type-Ib/c or type-IIb supernova. Further monitoring of this peculiar event is encouraged.