How big can stars get?

The theoretical size limit for the biggest stars keeps going up!

Today, it’s thought stars can’t be more massive than 150 times our sun’s mass. But, for a while, scientists thought they had found something even bigger in the star cluster Pismis 24.

Pismis 24 lies 8,000 light-years away in the direction of the constellation Sagittarius. A star in its midst – Pismis 24-1 – was thought to be 200 to 300 times our sun’s mass. But, in 2007, this object was revealed to be not one but three stars, orbiting each other.

In 2009, EarthSky spoke with Jesus Maiz Apellaniz, an astronomer with the Andalucia Institute of Astrophysics in Spain. Maiz Apellaniz said that stars like those in this system are bright, a million times or more brighter than our sun. But this sort of star can be hard to find. They’re short-lived and far away, in this case about 8,000 light-years from Earth.

He added that the birth place for stars are usually clouds that have large amounts of dust, and dust obscures the light from the stars and makes them very hard to detect.

Each of the stars in Pismus 24-1 are still very massive, between 60 and 100 times as massive as our sun. But theories suggest that a star can’t be more massive than 150 solar masses.

With this system now known to be several stars instead of one, the star “Eta Carinae” remains a good candidate for the title of most massive star known. It’s somewhere around the theoretical mass limit of 150 solar masses.

EarthSky

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