A newly discovered star breaks the galactic speed record for travelling at a velocity of 1,200 kilometers per second (2.7 million mph). The star is travelling at such a high speed, it will be able to break free from the gravity of our galaxy. The star was ejected from a thermonuclear supernova explosion, according to a press release from the Keck Observatory in Hawaii.
The data was obtained using the W. M. Keck Observatory and Pan-STARRS1 telescopes on Hawaii. The results will be published in the journal Science.
Stars like our sun are tied to the galaxy by gravity and orbit with moderate speeds, but a few hypervelocity stars are such speed demons that they are unbound - meaning, they are moving so fast that they will break through the galaxy and end up as intergalactic wanderers.
Stephan Geier from the European Southern Observatory and his team observed the high-velocity star know as US 708 with the Echellette Spectrograph and Imager instrument on the 10-meter Keck II telescope to measure its distance and velocity. By combining measurements from the archives with the new data, the team was able to obtain the peripheral component of the star's velocity (across our line of sight).
US 708 has been determined to be moving at a speed of 1,2000 kilometers per second, which is much faster than any previously know hypervelocity stars in the Milky Way. Also, perhaps more surprisingly, the trajectory of the speedy star means the supermassive black hole in the core of our galaxy could not have been the source of the star-on-the-run.
Another odd notation: US 708 is rotating, which is not a common property for hypervelocity stars. US 708 is a compact helium star which scientists believe could have been formed by interaction with a companion. That means, US 708 possibly resided in an ultracompact binary system in which helium was transferred to a massive white dwarf companion triggering a thermonuclear explosion of a type Ia supernova. Another way to say that is US 708 was ejected - quite violently - from the disrupted binary.
