Resurrected supernova provides missing link between two types

Astronomers have found a supernova exhibiting unprecedented rebrightening at millimeter wavelengths, offering an intermediate case between two kinds of supernovae: these of solitary stars and people in close-binary methods.

Many large stars finish their lives in a catastrophic explosion often known as a supernova (SN). Supernovae enhance quickly in brightness, after which fade over the course of a number of months.

Astronomers have lengthy recognized that the presence or absence of a detailed binary companion can have an effect on the evolution of massive stars. In a detailed binary system, gravitational interactions with the binary companion will strip massive quantities of fabric from the SN progenitor lengthy earlier than the ultimate explosion. In these circumstances, the progenitor will probably be quiet up till the time of the particular SN. However, within the case of an SN progenitor with no binary companion or a distant companion, main as much as the SN explosion the progenitor will hold most of its preliminary mass.

Astronomers wished to know what occurs when the binary is just not too shut and never too distant. The break got here when a global analysis workforce, led by Keiichi Maeda (Professor on the Graduate College of Science, Kyoto College) and Tomonari Michiyama (ALMA Joint Postdoctoral Fellow on the Graduate College of Science, Osaka College), used ALMA (The Atacama Massive Millimeter/submillimeter Array) to watch a supernova often known as SN 2018ivc because it dimmed for about 200 days after the preliminary explosion.

The outcomes confirmed that SN 2018ivc was an uncommon object, so the workforce determined to investigate cross-check it once more, at about 1,000 days after the explosion. They discovered that the item was truly rebrightening, the primary time this phenomenon had ever been noticed in millimeter wavelength radiation.

Comparability to numerical modeling means that interplay with an intermediate-distance binary companion about 1500 years earlier than the SN explosion created a big hole shell of circumstellar medium. At 200 days after the SN, the ejecta flying out from the explosion had but to succeed in the shell. Then someday between 200 and 1,000 days, the ejecta collided with the circumstellar medium.

These outcomes appeared as “Resurrection of Kind IIL Supernova 2018ivc: Implications for a Binary Evolution Sequence Connecting Hydrogen-rich and Hydrogen-poor Progenitors” in The Astrophysical Journal Letters on March 1, 2023.