Just How Massive Can Stars Get? Maybe Not Quite As Massive as we Thought
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Loading... - Ibrahim Yakubu
- 23 Aug 2022
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Massive stars — I mean truly massive, with 20 or more times the Sun’s mass — are terrifyingly powerful.
The energy they produce scales steeply with mass, so at the top end of this range stars can blast out so much light they can be seen in other galaxies with small telescopes, and would cook any planets they have to a crisp. They can light up entire nebulae, and when they explode at the ends of their short, violent lives they can outshine entire galaxies. Galaxies plural.
But how massive can stars get? It’s an important question in astronomy. We have a decent grasp of how stars like the Sun behave, but as you add more mass to them their behavior can get wonky. They can become unstable, pulsating and even undergoing explosions that are just this side of a catastrophic supernova.
Also, when massive stars explode they seed the galaxy around them with heavy elements like iron that they make during their lifetime. Those elements are necessary to make planets, and life. We literally owe our existence to massive stars going supernova.
And theoretically speaking we’d like to know what the upper mass limit is because it helps astronomers nail down how stars are born and how they live out their lives.
Up until recently that limit was thought to be over 300 times the mass of the Sun, which is huge. But now, new observations of the most massive star known show that might be an overreach. The new results imply that mass limit is more like 200 solar masses.
The star is called R136a1. It’s part of a tight cluster of very young stars called NGC 2070, which is in the center of the Tarantula Nebula, a vast and sprawling star-forming gas cloud in a satellite galaxy to the Milky Way called the Large Magellanic Cloud. It’s about 160,000 light years away.
Observing R136a1 at all is hard. The stars in the core of NGC 2070 are very closely packed together, and even with Hubble it’s tough to separate them. And that’s critical; you can’t observe a star and figure out what it’s doing if its light is blended with another nearby star. Read More...
