# MASTER OT J004207.99+405501.1/M31LRN 2015 Luminous Red Nova in M31: Discovery, Light Curve, Hydrodynamics, Evolution

## TL;DR

This paper reports the discovery and detailed photometric analysis of a luminous red nova in M31, exploring its light curve, hydrodynamics, and possible formation scenarios, suggesting star mergers as a key mechanism.

## Contribution

It presents new multicolor photometry data of a luminous red nova in M31 and discusses its implications for understanding star merger outbursts.

## Key findings

- Light curve analysis over 70 days reveals the nova's evolution.
- Estimated ejected shell mass and energy support star merger models.
- Proposes star merger as a natural stage in close-mass star evolution.

## Abstract

We report the discovery and multicolor (VRIW) photometry of a rare explosive star MASTER OT J004207.99+405501.1 - a luminous red nova - in the Andromeda galaxy M31N2015-01a. We use our original light curve acquired with identical MASTER Global Robotic Net telescopes in one photometric system: VRI during first 30 days and W (unfiltered) during 70 days. Also we added publishied multicolor photometry data to estimate the mass and energy of the ejected shell, and discuss the likely formation scenarios of outbursts of this type. We propose the interpretation of the explosion, that is consistent with the evolutionary scenario where star merger is a natural stage of the evolution of close-mass stars and may serve as an extra channel for the formation of nova outbursts.