It's the biggest gaggle of massive stars we've seen since the Academy Awards: New images from The Hubble Space Telescope show a cluster of nine monster stars — each one more than 100 times more massive than our sun. One of them is the previously discovered R136a1, which is the most massive, luminous star in the known universe
"Together these nine stars outshine the Sun by a factor of 30 million," according to a statement from the European Space Agency, which operates the telescope with NASA.
In addition to those nine headliners, the young star cluster R136 — located about 170,000 light years away in the Tarantula Nebula — also contains dozens of stars of at least 50 solar masses.
"Because they are so massive, they are all close to their so-called Eddington limit, which is the maximum luminosity a star can have before it rips itself apart; and so they've got really powerful outflows. They are shedding mass at a fair rate of knots," the University of Sheffield's Paul Crowther told the BBC. Crowther is the lead author of a study on the newly imaged stars, set to be published soon in the Monthly Notices of the Royal Astronomical Society.
According to Crowther and his colleagues, these stars are shedding an Earth's mass worth of gas and dust each month — so they won't live for very long. Stars as massive as these only live for a couple million years or so, which is why they're so rare in older galaxies like our own.
With so many of the massive, fast-dying stars in close proximity, the researcher say it's likely some of them will form black holes that will eventually merge — like the pair observed during the first detection of gravitational waves. It's possible that one day this very star cluster will send some of the same signatures careening our way.
Little is known about stars of this mass — in fact, when the first four stars in R136 were discovered in 2010, researchers were shocked to find that stars could even get so massive. But probing more clusters like this one will help scientists puzzle out their origins.
“There have been suggestions that these monsters result from the merger of less extreme stars in close binary systems. From what we know about the frequency of massive mergers, this scenario can’t account for all the really massive stars that we see in R136, so it would appear that such stars can originate from the star formation process," study author Saida Caballero-Nieves said in a statement.
Correction: An earlier version of this post mistakenly attributed a quote to Crowther instead of Caballero-Nieves. We regret the error.