# Progenitor candidate for the type II-P supernova SN 2018aoq in NGC 4151

## TL;DR

This paper identifies a likely red supergiant progenitor for SN 2018aoq in NGC 4151, estimates its distance and properties, and suggests it originated from a star of about 10 solar masses.

## Contribution

It provides the first progenitor candidate for SN 2018aoq, combining pre- and post-explosion data with spectral and photometric analysis to estimate progenitor characteristics.

## Key findings

- Distance to NGC 4151 is 18.2 Mpc based on standard candle method.
- Progenitor is an M-type red supergiant with about 10 solar masses.
- SN 2018aoq has intermediate brightness and low expansion velocities.

## Abstract

We present our findings based on pre- and post-explosion data of the type II-Plateau SN 2018aoq that exploded in NGC 4151. As distance estimates to NGC 4151 vary by an order of magnitude, we utilised the well-known correlation between ejecta velocity and plateau brightness, i.e. the standard candle method, to obtain a distance of 18.2$\pm$1.2 Mpc, which is in very good agreement with measurements based on geometric methods. The above distance implies a mid-plateau absolute magnitude of $M_{V}^{50}=-15.76\pm$0.14 suggesting that it is of intermediate brightness when compared to IIP SNe such as SN 2005cs at the faint end, and more typical events such as SN 1999em. This is further supported by relatively low expansion velocities (Fe II $\lambda$5169 $\sim$3000 km s$^{-1}$ at +42 d). Using archival HST/WFC3 imaging data, we find a point source coincident with the supernova position in the F350LP, F555W, F814W, and F160W filters. This source shows no significant variability over the $\sim$2 month time span of the data. From fits to the spectral energy distribution of the candidate progenitor, we find $\log\left(L/L_\odot\right)\sim 4.7$ and $T_{\mathrm{eff}}\sim 3.5$ kK, implying an M-type red supergiant progenitor. From comparisons to single and binary star models, we find that both favour the explosion of a star with a zero-age main sequence mass of $\sim$$10 M_\odot$.