Letter to the Editor

A progenitor candidate for the type II-P supernova SN 2018aoq in NGC 4151

¹ Astrophysics Research Centre, School of Mathematics and Physics, Queen’s University Belfast, Belfast BT7 1NN, UK
e-mail: doneill955@qub.ac.uk
² Department of Physics and Astronomy, Vesilinnantie 5, University of Turku, 20014 Turku, Finland
³ School of Physics, O’Brien Centre for Science North, University College Dublin, Belfield Dublin 4, Ireland
⁴ INAF – Osservatorio Astronomico di Padova, Vicolo dell’Osservatorio 5, 35122 Padova, Italy
⁵ Department of Physics, Florida State University, Tallahassee, FL 32306, USA
⁶ Institute of Space Sciences (ICE, CSIC), Campus UAB, Carrer de Can Magrans s/n, 08193 Barcelona, Spain
⁷ Institut d’Estudis Espacials de Catalunya (IEEC), c/Gran Capitá 2-4, Edif. Nexus 201, 08034 Barcelona, Spain
⁸ Warsaw University Astronomical Observatory, Al. Ujazdowskie 4, 00-478 Warszawa, Poland

Received: 2 November 2018
Accepted: 3 December 2018

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 ± 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_V⁵⁰ = − 15.76 ± 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 IIλ5169 ∼ 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 ∼2 month time span of the data. From fits to the spectral energy distribution of the candidate progenitor, we find log(L/L_⊙) ∼ 4.7 and T_eff ∼ 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 ∼10 M_⊙.