Two Dwarf Stars Orbiting Each Other Release Significant Gravitational Waves

A recent innovation is placing two with dwarf stars, which are an excellent source of gravitational waves. Every 1201 seconds, the equivalent of 20 minutes, the two dwarfs in the binary system are orbiting each other. The system is an exceptional discovery because of having one of the shortest periods of detached binaries. This offers researchers the possibility of thorough research of their gravitational waves.

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https://www.sciencealert.com/astronomers-say-this-binary-star-is-the-first-gravitational-wave-source-of-its-kind-ever-detected

> The system is an exceptional discovery because of having one of the shortest periods of detached binaries.

Ooh.

The key word here is “detached”. There’s a continuum of binary systems between detached stars, stars in kissing contact, and peanut-shaped single stars. The only obvious difference is the period of rotation.

Tau.Neutrino said:

more on story here
https://www.sciencealert.com/astronomers-say-this-binary-star-is-the-first-gravitational-wave-source-of-its-kind-ever-detected

> in 6 or 7 million years they will merge into a single, more massive white dwarf

That’s a short time for a star.

But how do you get white dwarfs this close in the first place? They have had to pass through red giant stages, at which point the companion star would have been well and truly swallowed up.

mollwollfumble said:

Tau.Neutrino said:

more on story here
https://www.sciencealert.com/astronomers-say-this-binary-star-is-the-first-gravitational-wave-source-of-its-kind-ever-detected

> in 6 or 7 million years they will merge into a single, more massive white dwarf

That’s a short time for a star.

But how do you get white dwarfs this close in the first place? They have had to pass through red giant stages, at which point the companion star would have been well and truly swallowed up.

> White dwarfs are the remnants of stellar cores, left over when stars like our own Sun have exhausted their fuel. J2322+0509 is a detached binary – it contains two white dwarfs with helium cores, swirling shockingly close, but not sharing any matter.

Oh, I think I get it. This was originally one star, not two, one star spinning extremely rapidly. As the red giant changed into a planetary nebula and shrank towards a white dwarf its rotation speeded up like an ice skater bringing her arms in. The resultant spin was too fast for a single white dwarf and it split into two.