Artist’s impression of helium-rich materials from a companion star accreting onto a white dwarf. Earlier than the explosion, a considerable amount of materials is stripped from the companion. The analysis workforce hopes to make clear the connection between the emitted sturdy radio waves and this stripped materials. Credit score: Adam Makarenko/W. M. Keck Observatory
Within the newest concern of the journal Nature, astronomers from Stockholm College reveal the origin of a thermonuclear supernova explosion. Robust emission traces of helium and the primary detection of such a supernova in radio waves present that the exploding white dwarf star had a helium-rich companion.
Researchers from Stockholm University have discovered a thermonuclear supernova’s origin traced to a helium-rich companion star of a white dwarf. This first-ever detection of a supernova in radio waves sheds light on the nature and processes leading to Type Ia supernovae, crucial for measuring the universe’s expansion. The finding helps resolve the long-standing question about the process leading to the explosion of a white dwarf star and the nature of its progenitor, identified here as a helium star that had lost much of its material just prior to the white dwarf’s explosion.
Supernovae of Type Ia are important for astronomers since they are used to measure the expansion of the Universe. However, the origin of these explosions has remained an open question. While it is established that the explosion is that of a compact white dwarf star somehow accreting too much matter from a companion star, the exact process and the nature of the progenitor are not known. The new discovery of supernova SN 2020eyj established that the companion star was a helium star that had lost much of its material just prior to the explosion of the white dwarf.
Artist impression of the double star system with a compact white dwarf star accreting matter from a helium-rich donor companion, surrounded by dense and dusty circumstellar materials. It was the interplay of the exploded star and the fabric left over from this companion that gave rise to the sturdy radio sign and the conspicuous helium traces within the optical spectra of SN 2020eyj. Credit score: Adam Makarenko/W. M. Keck Observatory
“As soon as we noticed the signatures of sturdy interplay with the fabric from the companion we tried to additionally detect it in radio emission,” explains Erik Kool, post-doc on the Division of Astronomy at Stockholm College and lead writer of the paper. “The detection in radio is the primary one among a Kind Ia supernova – one thing astronomers have tried to do for many years.”
Supernova 2020eyj was found by the Zwicky Transient Facility digicam on Palomar mountain, the place the Oskar Klein Centre at Stockholm College are members.
“The Nordic Optical telescope on La Palma was basic for following up this supernova,” says Professor Jesper Sollerman on the Division of Astronomy and co-author of the paper.
“As have been spectra from the massive Keck telescope on Hawai’i that instantly revealed the very uncommon helium-dominated materials across the exploded star.”
Erik Kool (middle) and Joel Johansson (left) are post-docs on the Oskar Klein Centre at Stockholm College and lead authors of this paper along with professor Jesper Sollerman (proper) from the Division of Astronomy. Credit score: Magnus Näslund
“That is clearly a really uncommon Kind Ia supernova, however nonetheless associated to those we use to measure the growth of the universe,” provides Joel Johansson from the Division of Physics.
“Whereas regular Kind Ia supernovae seem to at all times explode with the identical brightness, this supernova tells us that there are numerous completely different pathways to a white dwarf star explosion,” he provides.
Reference: “A radio-detected sort Ia supernova with helium-rich circumstellar materials” by Erik C. Kool, Joel Johansson, Jesper Sollerman, Javier Moldón, Takashi J. Moriya, Seppo Mattila, Steve Schulze, Laura Chomiuk, Miguel Pérez-Torres, Chelsea Harris, Peter Lundqvist, Matthew Graham, Sheng Yang, Daniel A. Perley, Nora Linn Strotjohann, Christoffer Fremling, Avishay Gal-Yam, Jeremy Lezmy, Kate Maguire, Conor Omand, Mathew Smith, Igor Andreoni, Eric C. Bellm, Joshua S. Bloom, Kishalay De, Steven L. Groom, Mansi M. Kasliwal, Frank J. Masci, Michael S. Medford, Sungmin Park, Josiah Purdum, Thomas M. Reynolds, Reed Riddle, Estelle Robert, Stuart D. Ryder, Yashvi Sharma and Daniel Stern, 17 Could 2023, Nature.
DOI: 10.1038/s41586-023-05916-w
The paper “A radio-detected Kind Ia supernova with helium-rich circumstellar materials” is revealed in Nature and is led by Erik Kool from the Division of Astronomy at Stockholm College and describes the primary radio detection of a Kind Ia supernova. Co-authors from Stockholm College are Joel Johansson, Jesper Sollerman, Steve Schulze, Peter Lundqvist, Sheng Yang, and Conor Omand. This work concerned researchers from institutes internationally, together with Caltech, Weizmann Institute, IAA-CSIC, NAOJ, Macquarie College, and Trinity Faculty Dublin.
Funding: Vetenskapsrådet (Swedish Analysis Council), Wenner-Gren Basis