Exploding star makes a black hole and eats companion

Supernovae are the explosions of massive stars.  Supernova SN 2022jli was discovered in May 2022 in the nearby (75 million lightyears) galaxy NGC 157 in the constellation Cetus.  Detailed monitoring of the fading supernova using the Zwicky Transient Facility at Palomar showed a periodic change in brightness, implying that two objects were involved in the deadly dance.

Artist impression of the supernova explosion. SN 2022jli occurred when a massive star died in a fiery explosion, leaving behind a compact object — a neutron star or a black hole. This dying star had a companion which survived this violent event. The periodic interactions between the compact object and its companion lead to periodic changes in the observed light curve, which revealed that the supernova explosion had indeed originated from a binary system and resulted in a compact object. Credit: ESO/L. Calçada

– People believe that a compact remnant is produced at the centre of a massive star explosion, says lead author Ping Chen from the Weizmann Institute of Science, Israel.
– But the direct link between supernova explosions and newly formed compact objects is elusive. In this work, we establish such a direct link.

The link is provided by the periodic nature of the brightness fluctuations, the object got slightly brighter every 12.4 days. Spectroscopic evidence showed that this was connected to material moving back and forth in the system.

– We used many different telescopes to monitor this object over several months, says Jesper Sollerman from Stockholm University, one of the lead-investigators in this study. This included the ZTF camera, the Nordic Optical Telescope on La Palma as well as the European Southern Observatory Very Large Telescope in Chile.

The interpretation forwarded in the Nature article is that a compact object orbits a companion star and is regularly stripping material from this star. It is well known that most massive stars have companions, but the direct evidence for this in a supernova explosion has been missing.

My best guess is that this transient is powered by a black hole that was created in the supernova explosion

– My best guess is that this transient is powered by a black hole that was created in the supernova explosion, and that was slowly accreting material from the more extended companion star, explains Jesper Sollerman.

The paper

A 12.4 day periodicity in a close binary system after a supernova is published in Nature and is led by Ping Chen from the Weizmann Institute in Israel.  From Stockholm university participated professor Jesper Sollerman from the Department of Astronomy and also former Stockholm researchers Steve Schulze and Sheng Yang from the Oskar Klein Centre.

Contact

Jesper Sollerman, Department of Astronomy, Stockholm University, jesper@astro.su.se

Further reading

The paper in Nature:  https://www.nature.com/articles/s41586-023-06787-x
ArXiv link: https://arxiv.org/abs/2310.07784    
Press release at ESO: https://www.eso.org/public/news/eso2401/
Zwicky Transient Facility; https://www.ztf.caltech.edu