Letter to the Editor

The impostor revealed: SN 2016jbu was a terminal explosion

¹ School of Physics, O’Brien Centre for Science North, University College Dublin, Belfield, Dublin 4 D04 V1W8, Ireland
e-mail: sean.brennan2@ucdconnect.ie
² INAF – Osservatorio Astronomico di Padova, vicolo dell’Osservatorio 5, Padova 35122, Italy
³ Institute of Space Sciences (ICE, CSIC), Campus UAB, Carrer de Can Magrans s/n, 08193 Barcelona, Spain
⁴ Caltech Spitzer Science Center, Caltech/IPAC, Mailcode 100-22, Pasadena, CA 91125, USA
⁵ Department of Physics, University of Warwick, Coventry CV4 7AL, UK

Received: 14 June 2022
Accepted: 17 August 2022

Abstract

In this Letter, we present recent observations from the Hubble Space Telescope of the interacting transient SN 2016jbu at +5 yr. We find no evidence for any additional outburst from SN 2016jbu, and the optical source has now faded significantly below the progenitor magnitudes from early 2016. Similar to recent observations of SN 2009ip and SN 2015bh, SN 2016jbu has not undergone a significant change in colour over the past 2 years, suggesting that there is a lack of ongoing dust formation. We find that SN 2016jbu is fading more slowly than expected of radioactive nickel, but faster than the decay of SN 2009ip. The late-time light curve displays a non-linear decline and follows on from a re-brightening event that occurred ∼8 months after peak brightness, suggesting CSM interaction continues to dominate SN 2016jbu. While our optical observations are plausibly consistent with a surviving, hot, dust-enshrouded star, this would require an implausibly large dust mass. These new observations suggest that SN 2016jbu is a genuine, albeit strange, supernova, and we discuss the plausibility of a surviving binary companion.