Discovered in 2017 and recently observed at the University of Canterbury’s John Astronomical Observatory, the four-star system may represent a new channel in which thermonuclear supernova explosions can occur in space. Nature Astronomy Today (May 13) by an international team of astronomers.
The rare double binary system HD74438 was discovered in the Vela constellation in 2017 using the Gaia-ESO survey, which characterizes more than 100,000 stars in our Milky Way galaxy.
Follow-up observations of the HD74438 have been obtained over the years to accurately track the orbits of stars in the quadruple system. Observations were made using high-resolution spectroscopes at the University of Canterbury at the University of Canterbury Much in New Zealand and a large telescope in South Africa in South Africa.
Astronomers have confirmed that the four stars of this star are composed of four gravitationally bound stars.
The quartet is a member of the young open cluster IC 2391, the youngest (only 43 million years ago) spectroscopic quadruple ever discovered in the Milky Way galaxy, and among the quadruple clusters with the shortest outer orbital period. In (6 years).
In Nature Astronomy In a paper published today, the authors show that the gravitational effect of the outer binary system alters the orbit of the inner binary, making it more eccentric. State-of-the-art simulations of future evolution of this system show that such gravitational dynamics can lead to one or more collisions and merger events that produce evolved dead stars ().White dwarf) Has a mass just below the Chandrasekhar limit. As a result of mass transfer or mergers, these white dwarfs can cause thermonuclear supernova explosions.
Astronomers involved in this study include the director of the John Astronomical Observatory at the University of Canterbury and Associate Professor Karen Polard of the Faculty of Physics and Chemistry at the University of Canterbury. Dr. C. Claire Wally and Professor Jerry Gilmore, UC graduates of the Institute of Astronomy, University of Cambridge, UK (first UC student with a PhD in Astronomy)
Associate Professor Polard states that the 1.0m McClellan telescope at the University of Canterbury John Astronomical Observatory in Tekapo used a Hercules spectroscope to make high-precision, high-resolution spectroscopic observations.
“Our sun-like stars end their life as small, dense dead stars known as white dwarfs. The mass of white dwarfs is the so-called Chandrasekhar limit (about 1.4 times the mass of the Sun). Can’t be exceeded, “she says. To tell. “If so, due to mass transfer or merger events, it can collapse and produce thermonuclear supernovae. Interestingly, currently 70% to 85% of all thermonuclear supernovae are Chandrasé. Suspected to be due to an explosion of white dwarfs with masses below Karl. As a result of mass transfer or mergers, these white dwarfs can explode as thermonuclear supernova explosions. “
Therefore, the evolution of stellar quadrupoles, such as the HD 74438, represents a new promising channel for forming thermonuclear supernova explosions in space, says Associate Professor Polard.
Binary stars are now recognized to play a major role in a wide range of astrophysical events, and binary mergers are responsible for the detection of recent gravitational wave emissions. Binaries also allow us to derive basic stellar parameters such as mass, radius, and luminosity with better accuracy compared to a single star. They represent gems on which various astrophysical topics depend.
Four times a star represents only a small part (a few percent) of all multiple systems. For such complex evolutions of higher-order multiples, Mass transfer And the collision leads to a merger, which is also a potential precursor of thermonuclear supernovae. These supernovae represent standard illuminants for fixing the cosmic distance scale, even though the evolutionary channels leading to such supernova explosion precursors are still highly debated.
The paper “Spectroscopic quadrupole as a possible precursor of subchandra secal type Ia supernovae” was published in. Nature Astronomy..
Thibault Merle et al, a spectroscopic quadruple as a possible precursor of subchandra secal type Ia supernovae, Nature Astronomy (2022). DOI: 10.1038 / s41550-022-01664-5
Canterbury Christ Church University
Quote: Astronomers discover four stars that can cause a supernova explosion (May 13, 2022).
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Astronomers Discover Four Stars That Can Cause a Supernova Explosion
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