Massive Stars
Written by Fraser Cain
Since they're all just made of hydrogen and helium, when it comes to stars, mass is everything. The amount of mass that a star has defines its luminosity, size and even how long it will live. The most massive stars in the Universe really live fast and die hard; they can amass more than 100 times the mass of the Sun, and will only live a few million years before detonating as supernovae.
How massive is massive? Some astronomers think that the theoretical limit for stellar mass is about 150 times the mass of the Sun, beyond this limit powerful stellar winds will push away infalling material before it can join the star. And stars with 150 solar masses have been observed, at least theoretically.
The most accurate way to measure the mass of an object like a star is if it's in a binary system with another object. Astronomers can calculate the mass of the two objects by measuring how they orbit one another. But the most massive stars ever seen don't have any binary companions, so astronomers have to guess at how massive they are. They estimate the star's mass based on its temperature and absolute brightness.
There are dozens of known stars estimated to have 25 times the mass of the Sun. Here's a list of the most massive known stars:
- HD 269810 (150 solar masses)
- Peony Nebula Star (150 solar masses)
- Eta Carinae (150 solar masses)
- Pistol Star (150 solar masses)
- LBV 1806-20 (130 masses)
All of these stars are supergiant stars, which formed inside the largest clouds of gas and dust. Stars this large aren't long for the Universe. They burn tremendous amounts of fuel and can be 500,000 times more luminous than the Sun.
Perhaps the most familiar, extremely massive star is Eta Carinae, located about 8,000 light years from Earth. Astronomers think it has an estimated mass of between 100 and 150 solar masses. The star is probably less than 3 million years old, and it's believed that it has less than 100,000 years left to live. When it detonates, Eta Carinae's supernova will be bright enough to see in the day, and you could read a book with it at night.
We have written many articles about stars on Universe Today. We've done an article about the biggest star in the Universe, and several articles about Eta Carinae's impending explosion.
Want more information on stars? Here's NASA's World Book on Stars, and more information from NASA's imagine the Universe.
We have recorded several episodes of Astronomy Cast about stars. Here are two that you might find helpful: Episode 12: Where Do Baby Stars Come From, and Episode 13: Where Do Stars Go When they Die?
Filed under: Astronomy
