Astronomers report discovery of the closest ultrastripped supernova: SN 2021agco in UGC 3855

Astronomers report the invention of a brand new ultrastripped supernova within the galaxy UGC 3855. The supernova was detected utilizing the Half Meter Telescope (HMT) on the Xingming Observatory in China. The discovering was detailed in a paper printed October 7 on the pre-print server arXiv.

Supernovae (SNe) are highly effective and luminous stellar explosions that would assist us higher perceive the evolution of stars and galaxies. Astronomers divide supernovae into two teams primarily based on their atomic spectra: Sort I and Sort II. Sort I SNe lack hydrogen of their spectra, whereas these of Sort II showcase spectral traces of hydrogen.

Sort Ib supernovae (SNe Ib) are a subclass of stripped-envelope core-collapse SNe. They’re shaped when a large star, with its outer envelope of hydrogen stripped away, collapses beneath its personal gravity. Furthermore, astronomers additionally distinguish ultrastripped-envelope SNe (USSNe), exhibiting spectral options just like these of SNe Ib/Ic, however comparatively faint. In these uncommon SNe, the progenitor envelope has been extraordinarily stripped earlier than explosion.

Now, a group of astronomers led by Shengyu Yan of the Tsinghua College in Beijing, China, experiences the discovering of a peculiar Sort Ib USSNe. The supernova was first recognized with HMT on December 5, 2021 and acquired designation SN 2021agco.

“On this paper, we current the invention and research of a brand new ultrastripped supernova, SN 2021agco,” the researchers wrote.

SN 2021agco was detected at a distance of some 130 million gentle years, in a comparatively outdated intermediate spiral galaxy generally known as UGC 3855—about 15,600 light years from the middle of the galaxy. The supernova had a really quick evolution, reaching the height of −16.06 magazine inside solely 2.4 days after the explosion.

The research discovered that ejecta mass of SN 2021agco was about 0.26 solar lots and the kinetic vitality of the supernova was calculated to be at a stage of 95.7 quindecillion erg. The researchers estimated that the progenitor of SN 2021agco had an envelope with a radius of about 78.4 solar radii, a mass of 0.1 solar lots, and an injection vitality 89.3 quindecillion erg.

In line with the authors of the paper, the findings recommend that the progenitor of SN 2021agco suffered violent mass loss and nearly all of its outer layer was stripped earlier than the explosion. Primarily based on the obtained outcomes, they categorised SN 2021agco as an ultrastripped SN Ib—the closest to Earth object of this subtype.

The observations additionally unveiled some data relating to the properties of the supernova’s host—UGC 3855. The astronomers discovered that the galaxy is roughly 10.6 billion years outdated, has a mass of some 2.6 billion solar lots, and a comparatively low star-formation charge of 0.2 solar masses per 12 months.

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