# Observational properties of a Type Ib Supernova MASTER OT J120451.50+265946.6 in NGC 4080

## TL;DR

This paper presents detailed photometric and spectroscopic observations of the Type Ib supernova MASTER OT J120451.50+265946.6, revealing its decline rate, spectral features, and progenitor characteristics based on nebular phase analysis.

## Contribution

It provides comprehensive observational data and analysis of a Type Ib supernova, including progenitor mass estimation and nebular spectral properties, which are novel for this event.

## Key findings

- Decline rate faster than similar SNe 1999dn and 2009jf
- Normal Type Ib spectral features observed
- Progenitor estimated to be a massive WR star of ~20 M_sun

## Abstract

MASTER OT J120451.50+265946.6 (M12045), discovered by the MASTER Global Robotic Net, is a Type Ib supernova (SN) that exploded in NGC 4080. We present the {\it BVRI} photometric and spectroscopic observations upto $\sim$250 days since $B_{max}$. At the time of discovery the SN was a few weeks past maximum light and our observations capture the linearly declining light curve phase. M12045 declines faster as compared to SNe 1999dn and 2009jf at comparable epochs. Rigorous spectroscopic monitoring reveals that M12045 is a normal Type Ib SN. The analysis of the nebular phase spectra indicates that $\sim$ 0.90 M$_\odot$ of O is ejected in the explosion. The line ratio of [\ion{O}{I}] and [\ion{Ca}{II}] in the nebular phase supports a massive WR progenitor with main sequence mass of $\sim$ 20 M$_\odot$.