Neutron stars—the compact remains of massive stars that have gone supernova—are some of the most extreme objects in the universe, narrowly beaten by black holes (and, as we’ll talk about in future posts, active galaxies and such).
Dense balls of pure neutron material with diameters barely larger than Los Angeles, neutron stars have strong magnetic fields that produce beams of radiation at the magnetic poles. Their speedy rotation makes these beams sweep across the sky like a lighthouse.
When one of their beams crosses directly over Earth, human astronomers observe rapid pulses of light called pulsars.
These objects are whacky, to say the least. And there’s more…
When we talk about star death, we’re not really talking about death. We’re talking about the end of a functioning star. Astronomers tend to personify cosmic objects like stars, saying that they are born and die, when it’s more like they transition into something new.
With stars in particular, there’s two main courses their “life cycles,” such that they are, can take: one for massive stars and one for low-mass stars.
We can further subdivide low-mass star “deaths” into those of red dwarfs—like our nearest stellar neighbor, Proxima Centauri—and those of medium-mass stars, like the sun.
But before we dive into the final stages of these stellar life cycles, let’s review what kinds of stars we’re talking about here…
As with most questions in astronomy, the answer to that is not definitive. But stellar models can give us a pretty good idea.
Mathematical models of stars tell us that their life—or, to use a less personifying term, function—depends on the balance between two opposing forces: internal pressure and gravity.
Stars produce energy to function. They don’t just do this to light up our skies and provide for life on their orbiting worlds. They need to produce energy to constantly support the weight of their own mass.
The more massive stars are, the more energy they need to produce—and the reverse is true too. There has to be a balance.
But is there a limit? Is there a point where balance is impossible?