Yellow hypergiants are very uncommon, in fact there are only a dozen or so known in Milky Way Galaxy. The best-known among these dozen is Rho Cassiopeiae. Hypergiants are one of the the biggest and the brightest stars identified. Hypergiants are at a phase of their lives when they are unbalanced and varying rapidly. Due to this unpredictability, these entities also eject material outward, creating a large, stretched atmosphere around the star.
|Artist’s impression of the yellow hypergiant star HR 5171. Image credit: ESO.|
The newly discovered hypergiant star is HR 5171A. HR 5171A lies about 12,000 light-years away from Earth and has more than 1,300 times the diameter of the Sun. HR 5171A is one of the 10 biggest hypergiants stars discovered so far. It is 50 percent greater than gigantic Betelgeuse and around 1,000,000 times brighter than the Sun. The hypergiant is chunk of a binary star system, with the second partner star so close that it is in contact with the main giant star. Observations exhibited that “HR 5171A star has a very close binary partner, which was an actual disclosure,” described Dr Olivier Chesneau from the Observatoire de la Côte d’Azur in France, who is also the main author of a paper issued in the journal Astronomy & Astrophysics. HR 5171A and its partner star, HR 5171B, are so adjacent that they look like a single star and the entire system look like a huge peanut. Dr Chesneau and his associates made use of a procedure termed as interferometry to syndicate the light collected from multiple distinct telescopes, successfully generating a huge telescope up to 140 m in size.
By examining data on the star’s variable brightness, the group confirmed the object to be an eclipsing binary system where the minor partner star passes in front and behind the superior one as it orbits. In this case HR 5171A is orbited by its partner star every 1,300 days. HR 5171B is only faintly hotter than HR 5171 A’s.
Dr Chesneau said “The companion we have found is very significant as it can have an influence on the fate of HR 5171A, for example, stripping off its outer layers and modifying its evolution,”
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