Scientists using the W. M. Keck Observatory and Pan-STARRS1 telescopes on Hawaii have discovered a star that breaks the galactic speed record, traveling with a velocity of about 1,200 kilometers per second or 2.7 million miles per hour. This velocity is so high, the star will escape the gravity of our galaxy. In contrast to the other known unbound stars, the team showed that this compact star was ejected from an extremely tight binary by a thermonuclear supernova explosion. These results will be published in the March 6 issue of Science.
Stars like the Sun are bound to our Galaxy and orbit its center with moderate velocities. Only a few so-called hypervelocity stars are known to travel with velocities so high that they are unbound, meaning they will not orbit the galaxy, but instead will escape its gravity to wander intergalactic space.
A close encounter with the supermassive black hole at the centre of the Milky Way is typically presumed the most plausible mechanism for kicking these stars out of the galaxy. ...
Know the quiet place within your heart and touch the rainbow of possibility; be
alive to the gentle breeze of communication, and please stop being such a jerk. — Garrison Keillor
BDanielMayfield wrote:Are not ALL Supernovae "thermonuclear"?
No. Supernovae of type Ia are, since they result in binary systems where a white dwarf "sucks" material from its companion until its mass is large enough to ignite nuclear fusion again. On the other hand, type II supernovae result from the collapse of massive stars.
BDanielMayfield wrote:Are not ALL Supernovae "thermonuclear"?
No. Supernovae of type Ia are, since they result in binary systems where a white dwarf "sucks" material from its companion until its mass is large enough to ignite nuclear fusion again. On the other hand, type II supernovae result from the collapse of massive stars.
I'd say it depends on how we choose to use "thermonuclear". Certainly, a great deal of the energy released in type II supernovas is the product of thermonuclear reactions (that is, very high energy nuclear reactions), even if those supernovas are directly caused by gravitational collapse.
Simply saying "thermonuclear supernova" is a bit vague.
Chris
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Chris L Peterson
Cloudbait Observatory https://www.cloudbait.com
BDanielMayfield wrote:Are not ALL Supernovae "thermonuclear"?
No. Supernovae of type Ia are, since they result in binary systems where a white dwarf "sucks" material from its companion until its mass is large enough to ignite nuclear fusion again. On the other hand, type II supernovae result from the collapse of massive stars.
Good point, though. The ultrafast star is apparently an extremely compact helium star, which is a kind of star that may be produced when a red giant orbits close to a white dwarf and has its swollen atmosphere siphoned away from it onto the white dwarf. This scenario would explain not only the compact helium star, but also the type Ia supernova.
