Unveiling Supernova Beginnings through Radio Signal Discovery

This artistic representation illustrates a dual star system where a compact white dwarf star draws matter from a helium-enriched partner. The pair are encased in dense, dusty circumstellar material. The aftermath of the star explosion and the remnants from its partner gave rise to a powerful radio signal, prominent helium lines in the optical spectra, and infrared emission from SN 2020eyj. Credit: Adam Makarenko/W. M. Keck Observatory

A collective of international astronomers have unveiled the source of a thermonuclear supernova explosion. Prominent helium emission lines and the first-ever detection of such a supernova in radio waves suggest that the erupting white dwarf star was paired with a helium-rich companion.

Thermonuclear, or Type Ia, supernovae serve as key measures of the Universe’s expansion for astronomers. The origins of these explosions, however, have remained a mystery. It is known that these blasts involve a compact white dwarf star amassing excessive matter from a companion star, but the precise process and nature of the original star are unclear. The recent discovery of supernova SN 2020eyj affirmed that the partner star was a helium star, which had shed much of its substance just before the white dwarf’s explosion.

“As we noticed clear signs of strong interaction with the companion’s material, we endeavored to find the same in radio emissions,” states Erik Kool, post-doc at Stockholm University’s Department of Astronomy and the paper’s lead author. “This marks the first radio detection of a Type Ia supernova – a goal astronomers have been pursuing for decades.”

SN 2020eyj was pinpointed by the Zwicky Transient Facility camera on Palomar Mountain and monitored with various facilities, including the Nordic Optical Telescope (NOT) on La Palma, the large Keck telescope on Hawai’i, and the electronic Multi-Element Radio Linked Interferometer Network (e-MERLIN), a collection of seven radio telescopes in Great Britain.

Supernova 2020eyj also shone incredibly bright in the infrared spectrum, rivaling some of the most luminous supernovae observed at these wavelengths. This brightness is attributed to thermal emissions from interstellar dust particles mingling with the supernova-surrounding material.

“All radio, optical, and infrared observations align with the companion star shedding a significant amount of mass before the white dwarf’s explosion. This significant discovery enhances our understanding of white dwarf explosions as supernovae, which are utilized for cosmological measurements,” says Prof. Seppo Mattila of the Department of Physics and Astronomy at the University of Turku, a co-author of the paper who contributed primarily to interpreting the infrared and radio observations.

For additional information on this research:

Radio Signal Unveils Thermonuclear Supernova Explosion’s Source
First Discovery of Radio Waves from a Type Ia Supernova

Reference: “A radio-detected type Ia supernova with helium-rich circumstellar material” by Erik C. Kool et al., 17 May 2023, Nature.
DOI: 10.1038/s41586-023-05916-w

Erik Kool from the Department of Astronomy at Stockholm University led the study “A radio-detected Type Ia supernova with helium-rich circumstellar material,” which was published in Nature and marks the first radio detection of a Type Ia supernova. This research involved global collaborators from institutions including the University of Turku, Caltech, the Weizmann Institute, IAA-CSIC, NAOJ, Macquarie University, and Trinity College Dublin.

Frequently Asked Questions (FAQs) about Thermonuclear Supernova Origins

More about Thermonuclear Supernova Origins

• Radio Signal Reveals Origin of Thermonuclear Supernova Explosion
• First Detection of Radio Waves From Type Ia Supernova
• University of Turku, Department of Physics and Astronomy
• Stockholm University, Department of Astronomy
• W. M. Keck Observatory
• Zwicky Transient Facility camera
• Nordic Optical Telescope (NOT)
• e-MERLIN
• Palomar Mountain