The first radio detection illustrates the origin of supernovae Ia

May 17. (EUROPE PRESS) –

The first radio observation of a type Ia supernova has confirmed that It comes from a double star system made up of a white dwarf and a solar-type star.

These supernovae occur when a white dwarf, the “corpse” of a star similar to the Sun, absorbs material from a companion star and reaches a critical mass, equivalent to 1.4 solar masses, triggering an explosion whose luminosity will be, given its origin, similar in almost all cases. This uniformity made type Ia supernovae ideal objects for measuring distances in the universe, but the origin and nature of the parent system was unknown.

“When we saw, in the supernova SN2020eyj, signs of a strong interaction with the material of the companion star, we tried to observe the explosion in radio, something that had been tried without result for decades,” explains Erik Kool, a researcher at Stockholm University. and lead author of the new study, published by Nature.

Type Ia supernovae always contain a white dwarf, which receives material from its companion. However, it was unknown whether that companion was a white dwarf or a Sun-like star, something that could be revealed by radio images.

“This first radio detection of a type Ia supernova is a milestone that has allowed us to demonstrate that the white dwarf that exploded was accompanied by a normal, non-degenerate star, before the explosion,” says Javier Moldón, a researcher at the IAA-CSIC that participates in the discovery- In addition, with these observations we can estimate the mass and geometry of the material that surrounds the supernova, This allows us to better understand what the system was like before the explosion.”

This work, whose contribution in radio data was led by the IAA-CSIC, has made it possible to confirm that the material ejected in the supernova explosion collided, after traveling sixty days, with the material that surrounded the system, made up mostly of helium, making it indicating that the companion star was not a white dwarf. In addition, the models anticipated that the radio emission, if it existed, would take many months to be detectable and, in effect, the scientific team had to wait a year and a half to detect the radio counterpart of the supernova.

“The unusual light curve of SN 2020eyj, the infrared emission, the detection of helium emission lines and the unprecedented radio detection make this supernova unique, a treasure trove of information with implications in multiple fields of research,” says Miguel Pérez Torres. , IAA-CSIC researcher who participates in the work-. Studying more similar systems will allow us to better understand the origin of these standard candles and the chemical evolution of galaxies.”

“Now that we have shown that radio observations can provide direct and unique information to understand these types of supernovae, a path is open to study these systems with the new generation of radio instruments, such as the Square Kilometer Array Observatory (SKAO) in the future”, concludes Moldón.

The result has been possible thanks to e-MERLIN, a set of very high angular resolution radio telescopes, and the analysis of the data has been carried out from the Spanish prototype of the SKA Regional Center (SPSRC) of the IAA-CSIC, which has the support of the Severo Ochoa project of the IAA and that facilitates the processing of data from precursor observatories of the SKAO, such as e-MERLIN.