Radio signal reveals supernova origin

Date:
May 17, 2023
Source:
Stockholm University
Summary:
Astronomers reveal the origin of a thermonuclear supernova
explosion.

Strong emission lines of helium and the first detection of such a
supernova in radio waves show that the exploding white dwarf star
had a helium-rich companion.


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==========================================================================
FULL STORY ==========================================================================
In the latest issue of the journal Nature, astronomers from
Stockholm University reveal the origin of a thermonuclear supernova
explosion. Strong emission lines of helium and the first detection of
such a supernova in radio waves show that the exploding white dwarf star
had a helium-rich companion.

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 is 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.

"Once we saw the signatures of strong interaction with the material from
the companion we tried to also detect it in radio emission," explains Erik Kool, post-doc at the Department of Astronomy at Stockholm university and
lead author of the paper. "The detection in radio is the first one of a
Type Ia supernova - - something astronomers have tried to do for decades." Supernova 2020eyj was discovered by the Zwicky Transient Facility camera
on Palomar mountain, where the Oskar Klein Centre at Stockholm University
are members.

"The Nordic Optical telescope on La Palma was fundamental for following
up this supernova," says Professor Jesper Sollerman at the Department of Astronomy and co-author of the paper. "As were spectra from the large
Keck telescope on Hawai'i that immediately revealed the very unusual helium-dominated material around the exploded star." "This is clearly
a very unusual Type Ia supernova, but still related to the ones we use
to measure the expansion of the universe," adds Joel Johansson from the Department of Physics.

"While normal Type Ia supernovae appear to always explode with the same brightness, this supernova tells us that there are many different pathways
to a white dwarf star explosion," he adds.

* RELATED_TOPICS
o Space_&_Time
# Stars # Astronomy # Astrophysics # Galaxies #
Extrasolar_Planets # Space_Telescopes # Cosmology #
Black_Holes
* RELATED_TERMS
o Supernova o Crab_Nebula o Radio_telescope o Astronomy o
Star_Trek:_The_Original_Series o Planet o Gravitational_wave
o Meteor

========================================================================== Story Source: Materials provided by Stockholm_University. Note: Content
may be edited for style and length.


========================================================================== Related Multimedia:
*
Artist_impression_of_the_double_star_system_with_a_compact_white_dwarf
star_accreting_matter_from_a_helium-rich_donor_companion.

========================================================================== Journal Reference:
1. Erik C. Kool, Joel Johansson, Jesper Sollerman, Javier Moldo'n,
Takashi
J. Moriya, Seppo Mattila, Steve Schulze, Laura Chomiuk, Miguel
Pe'rez- 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, Daniel Stern. A radio-detected type Ia
supernova with helium-rich circumstellar material. Nature, 2023;
617 (7961): 477 DOI: 10.1038/s41586-023-05916-w ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2023/05/230517122109.htm

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