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Hasty demise of a lonely star

Supernova (SN) 2019bkc/ATLAS19dqr was recently discovered by the Asteroid Terrestrial-impact Last Alert System (ATLAS) and located in what appears to be a “hostless” environment.

2019.06.27 | Ole J. Knudsen

Supernova SN 2019bkc imaged with the NOT telescope on La Palma. Photo from the paper.

Supernova SN 2019bkc imaged with the NOT telescope on La Palma. Photo from the paper.

 

IFA's Max Stritzinger og Simon Holmbo are co-authors on a recent paper on this special supernova.

Upon obtaining a spectrum we soon realized it was a peculiar transient with similarities to several other well-observed fast transients with unknown origins. Followup imaging over the next several weeks revealed SN 2019bkc is the most rapidly-declining supernova yet studied. Comparison with a variety of progenitor scenarios (e.g., .Ia SN, ccSN with little radioactivity, ccSN with no radioactivity, electron-capture of massive AGB star, etc) provides little indication of the underlying nature of this object. Furthermore, SN 2019bkc serves as a lesson to transient search programs whom should consider to obtain spectral classification of such “hostless” transients as traditional programs would often assume such objects to be Galactic, cataclysmic variable outbursts. SN 2019bkc provides a significant challenge for existing models of fast- evolving SNe.

The red curve shows the rapid decline of the supernova SN 2019bkc in magnitudes (M). x-axis is in days. Illustration from the paper.

The paper, titled "The Most Rapidly-Declining Type I Supernova 2019bkc/ATLAS19dqr" was put on ArXive in this version on 8 May 2019.

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