Letter to the Editor

Revisiting the progenitor of the low-luminosity type II-plateau supernova, SN 2008bk

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, University of Turku, Vesilinnantie 5, Turku, 20014 Finland
³ School of Physics, O’Brien Centre for Science North, University College Dublin, Belfield, Dublin 4, Ireland
⁴ Nicolaus Copernicus Astronomical Centre, Warsaw, Poland
⁵ Universidad de Concepción, Departamento de Astronomía, Concepción, Chile
⁶ Núcleo de Astronomía de la Facultad de Ingeniería y Ciencias, Universidad Diego Portales, Av. Ejército 441, Santiago, Chile
⁷ Millennium Institute of Astrophysics, Santiago, Chile

Received: 28 September 2020
Accepted: 26 November 2020

Abstract

The availability of updated model atmospheres for red supergiants and improvements in single and binary stellar evolution models, together with previously unpublished data, prompted us to revisit the progenitor of the low-luminosity type II-plateau supernova (type IIP SN), SN 2008bk. Using mid-infrared (mid-IR) data in combination with dust models, we find that high-temperature (4250−4500 K), high extinction (E(B − V)> 0.7) solutions are incompatible with the data. We therefore favour a cool (∼3500−3700 K) progenitor with a luminosity of log(L/L_⊙) ∼ 4.53. Comparing with evolutionary tracks, we infer progenitor masses in the 8–10 M_⊙ range in agreement with some previous studies. This mass is consistent with the observed pattern of low-luminosity type IIP SNe coming from the explosion of red supergiant stars (RSGs) at the lower extremum for core collapse. We also present multi-epoch data for the progenitor, but do not find clear evidence of variability.