SN 2015as: A low luminosity Type IIb supernova without an early light curve peak

Understand

We present results of the photometric (from 3 to 509 days past explosion) and spectroscopic (up to 230 days past explosion) monitoring campaign of the He-rich Type IIb supernova (SN) 2015as.

• The {\it (B-V)} colour evolution of SN 2015as closely resemble those of SN 2008ax, suggesting that SN 2015as belongs to the SN IIb subgroup that does not show the early, short-duration photometric peak.
• The light curve of SN 2015as reaches the $B$-band maximum about 22 days after the explosion, at an absolute magnitude of -16.82 $\pm$ 0.18 mag.
• At $\sim$ 75 days after the explosion, its spectrum transitions from that of a SN II to a SN Ib.