This humongous star is more than 1,300 times bigger than our sun
HR 5171A, a 'yellow hypergiant star', the largest yellow star known so far, is also one million times brighter than the sun.
This artist鈥檚 impression shows the yellow hypergiant star HR 5171. This is a very rare type of star with only a dozen known in our galaxy. Its size is over 1300 times that of our Sun 鈥� one of the largest ten stars found so far. Observations with ESO鈥檚 Very Large Telescope Interferometer have shown that it is actually a double star, with the companion in contact with the main star.
ESO
Located 12,000 light-years from Earth, this colossal star is so bright that it is just about visible even with the naked eye. It is about one million times brighter than the Sun.
HR 5171A,聽a "yellow hypergiant star," measures more than 1,300 times the diameter of the Sun. It is the largest yellow star known so far.
Tt has a partner, too. 鈥淭he new observations also showed that this star has a very close binary partner, which was a real surprise,鈥� said Olivier Chesneau of the Observatoire de la C么te d鈥橝zur, Nice, France, who along with her team examined the yellow star. 鈥淭he two stars are so close that they touch and the whole system resembles a gigantic peanut.鈥�
The companion star that orbits around HR 5171A every 1,300 days is only slightly hotter than HR 5171A鈥檚 surface temperature, which is more than 9,000 degrees Fahrenheit. The two stars compose an "eclipsing binary system," in which the smaller companion passes in front and behind the larger one while orbiting.
鈥淭he companion we have found is very significant as it can have an influence on the fate of HR 5171 A, for example, stripping off its outer layers and modifying its evolution," Chesneau said.
In addition to being the biggest known yellow star, HR 5171A is one of the top ten biggest known stars. It is 50 percent larger than the red supergiant Betelgeuse located in the Orion constellation.
Scientists examined the star using a technique called interferometry, which combines light collected from several individual telescopes to create a giant virtual telescope measuring up to 460 feet. The star was seen using聽European Southern Observatory鈥檚 Very Large Telescope Interferometer in Chile.
A rare class of stars, yellow hypergiants are at a stage where they are undergoing rapid changes. The most famous among them is the Rho Cassiopeia.
Found in the constellation Cassiopeia, Rho Cassiopeia is located about 8,200 light years聽from Earth in the constellation Cassiopeia.
"HR 5171 A has been found to be getting bigger over the last 40 years, cooling as it grows, and its evolution has now been caught in action. Only a few stars are caught in this very brief phase, where they undergo a ," researchers noted in a press release by the European Southern Laboratory.