A team of Japanese researchers describes ways for seeing and perhaps predicting precursor signs for explosions from Local Type II and Galactic supernovae in a recent report published to High Energy Astrophysical Phenomena (SNe). This research has the potential to improve our understanding of how and when supernovae may occur across the cosmos (supernovae is the plural form of supernova) (SN). But how crucial is it to identify supernovae before they occur?
Dr. Daichi Tsuna, an astronomer from the University of Tokyo's Research Center for the Early Universe and the study's principal author, stated, "From my perspective, it is important in two ways." First, while we know that supernovae (SNe) are explosions that indicate the death of huge stars, we don't know what happens near the conclusion of their lives. In reality, SN antecedents, as shown by recent observational studies, are not anticipated by classic star evolution theory. Our article proposes that future observations will allow us to investigate this precursor in more depth, which will help us comprehend star development and enhance the present hypothesis.
Second, discovering an SN precursor would provide for an early warning of a near-future SN, as well as help to expand the available time frame for coordinating multi-messenger (light, neutrinos, and gravitational waves) studies.
The researchers created a theoretical model for such a discharge from a red supergiant star's mass outburst using the open-source program CHIPS (Complete History of Interaction-Powered Supernovae). This is noteworthy since the star Betelguese, which was detected to decline in brightness in 2019, generating speculation that it may have gone supernovae, is also a red supergiant star. As it turns out, Betelguese is reaching the end of its existence, but according to a 2021 research, it won't explode for another 100,000 years. But what impact may this research have on Betelguese?
Betelgeuse is a red supergiant, which is exactly the type of star researched in this article, according to Dr. Tsuna. As a result, if Betelgeuse explodes very soon, it may show this type of precursor emission right before the SN. Because Betelgeuse is so near to us, neutrino detectors may detect neutrinos released days before the SN. Even before the SN explosion, we can do multi-messenger astronomy.
According to the study's results, eruption light curves are fuelled by a transient shockwave pulse that lasts only a few days, followed by a much longer cooling discharge that lasts hundreds of days. This time is followed by a dim peak period fuelled by what is known as the bound envelope drawing back for lesser energy eruptions. According to the study's conclusion, such mass eruption episodes can serve as an early warning of a nearby SN in the near future, which will be significant for multi-messenger investigations of core-collapse SNe.
Dr. Tsuna, one thing I'd want to emphasize is that we have a bright future in detecting these fairly weak precursors. For example, in a few years, the Rubin Observatory will undertake wide-field survey observations with substantially higher sensitivity than current surveys. It would be sensitive enough to identify such emissions and might serve as a probe of the spectacular latter moments of a giant star's existence.
Journal Information: Daichi Tsuna, Yuki Takei, Toshikazu Shigeyama, Precursors of Supernovae from Mass Eruption: Prospects for Early Warning of Nearby Core-collapse Supernovae. arXiv:2208.08256v1 [astro-ph.HE], arxiv.org/abs/2208.08256