Skip to footer

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.

|
ESO
This artist’s 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 — one of the largest ten stars found so far. Observations with ESO’s Very Large Telescope Interferometer have shown that it is actually a double star, with the companion in contact with the main star.

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, 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. “The new observations also showed that this star has a very close binary partner, which was a real surprise,” said Olivier Chesneau of the Observatoire de la Côte d’Azur, Nice, France, who along with her team examined the yellow star. “The two stars are so close that they touch and the whole system resembles a gigantic peanut.”

The companion star that orbits around HR 5171A every 1,300 days is only slightly hotter than HR 5171A’s 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.

“The 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 European Southern Observatory’s 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 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 dramatic change in temperature as they rapidly evolve," researchers noted in a press release by the European Southern Laboratory.

You've read  of  free articles. Subscribe to continue.
Real news can be honest, hopeful, credible, constructive.
What is the Monitor difference? Tackling the tough headlines – with humanity. Listening to sources – with respect. Seeing the story that others are missing by reporting what so often gets overlooked: the values that connect us. That’s Monitor reporting – news that changes how you see the world.
editor@csmonitor.com
Subscribe
Mark Sappenfield
Editor

Dear Reader,

About a year ago, I happened upon this statement about the Monitor in the Harvard Business Review – under the charming heading of “do things that don’t interest you”:

“Many things that end up” being meaningful, writes social scientist Joseph Grenny, “have come from conference workshops, articles, or online videos that began as a chore and ended with an insight. My work in Kenya, for example, was heavily influenced by a Christian Science Monitor article I had forced myself to read 10 years earlier. Sometimes, we call things ‘boring’ simply because they lie outside the box we are currently in.”

If you were to come up with a punchline to a joke about the Monitor, that would probably be it. We’re seen as being global, fair, insightful, and perhaps a bit too earnest. We’re the bran muffin of journalism.

But you know what? We change lives. And I’m going to argue that we change lives precisely because we force open that too-small box that most human beings think they live in.

The Monitor is a peculiar little publication that’s hard for the world to figure out. We’re run by a church, but we’re not only for church members and we’re not about converting people. We’re known as being fair even as the world becomes as polarized as at any time since the newspaper’s founding in 1908.

We have a mission beyond circulation, we want to bridge divides. We’re about kicking down the door of thought everywhere and saying, “You are bigger and more capable than you realize. And we can prove it.”

If you’re looking for bran muffin journalism, you can subscribe to the Monitor for $15. You’ll get the Monitor Weekly magazine, the Monitor Daily email, and unlimited access to CSMonitor.com.

Subscribe to insightful journalism

QR Code to This humongous star is more than 1,300 times bigger than our sun
Read this article in
https://www.csmonitor.com/Science/2014/0312/This-humongous-star-is-more-than-1-300-times-bigger-than-our-sun
QR Code to Subscription page
Start your subscription today
https://www.csmonitor.com/subscribe