The pinwheel galaxy’s supernova progenitor lost mass several years before dying

Daichi Hiramatsu et al. / The Astrophysical Journal Letters, 2023

This led to the formation of dense circumstellar matter.

Astronomers have determined that the progenitor of the supernova SN 2023ixf, discovered in the Pinwheel Galaxy this year, was actively losing mass in the last 1-2 years before its death. This led to a slow breakthrough of the shock wave from the explosion through the dense circumstellar matter. The article was published in The Astrophysical Journal Letters. Most massive stars with masses greater than eight solar masses end their lives by gravitational core collapse when they begin to fusion iron, leading to Type II supernova explosions. To understand the mechanisms and features of supernova explosions, it is necessary to understand the properties of their progenitors, which is not so simple

Of particular interest is the progressive mass loss of red supergiants before the explosion, which is not predicted by standard theories of stellar evolution but has been repeatedly revealed from observational data. close. A team of astronomers led by Daichi Hiramatsu of the Harvard-Smithsonian Center for Astrophysics announced the results of observing supernova SN 2023ixf using telescopes at the Itagaki Observatory, Las Cumbres Observatory, Fred Lawrence Whipple Observatory and several other ground observatories. observatories as well as the WISE and Swift space telescopes.

Observations cover the period before the explosion and the first month after the outbreak was detected and include photometric and spectroscopic data. The researchers determined that the behavior of a supernova explosion is best suited to a model of shock wave interaction with dense matter around the star located within (3-7) × 1011 km from star. This can be explained by two models that show how a star loses mass before dying. If the loss is continuous it is characterized by a rate of 0.1 to 1 solar mass per year and occurs 1 to 2 years before the explosion, decreasing to 0.01 to 0.1 solar mass solar energy per year 0.4 to 0.7 years before the explosion.

If mass loss occurred by ejection of material, this occurred in the last year before the explosion, with emissions ranging from 0.3 to 1 solar mass.