Rendering of AR Scorpii in the Scorpius galaxy.

This is why one star is beating the lights out of the other

Contributed by
Aug 10, 2016

Something in the Scorpius constellation has claws.

Astronomers have shed new light on a misbehaving star about 380 light-years from Earth. The white dwarf of binary star AR Scorpii is throwing punches of radiation that make both the bully and its red dwarf rival pulse across the entire electromagnetic spectrum. Meaning, every frequency from the same UV radiation that makes you slather on SPF to the radio waves that power that heavy metal station which makes the neighbors stare.

The relationship between these two is literally a song of ice and fire. That glowing ball of crimson might look like it burns with the fury of Hades, but it’s a deceptively small star whose low luminosity keeps it relatively cool (for a celestial body of light, anyway) despite having the face of an inferno. Red dwarfs are late bloomers that grow at an excruciatingly slow rate. White dwarfs, in blazing contrast, are the scorching innards of what were once massive stars not unlike our sun—and this particular one’s temper is as hot as its temperature.

AR Scorpii was on scientists’ radar several decades ago, but the nature of the beast is just now starting to be understood. Before it reared its actual head, it was thought to be just another far-off star with fluctuating brightness. Astronomers re-examined it to find two stars locked in an eternal clash. “We realized we were seeing something extraordinary within minutes of starting to observe it,” said Prof. Tom Marsh of the University of Warwick, who leads the team revamping its previously mistaken identity. 

Hubble telescope footage of AR Scorpii.

Actual Hubble telescope footage of AR Scorpii, that ridiculously bright spot in the middle.

That the two stars got into an after-school brawl is both an understatement and an anomaly. Since they were first caught fighting last year, a brigade of telescopes including the Hubble Space Telescope, NASA’s Swift Satellite and the Very Large Telescope (best name ever) have revealed what is behind this interstellar drama.

AR Scorpii is has such an impressive range of frequencies because it shoots Phaser-like beams of electron emissions. These are released when its electrons are exposed to intense magnetic fields that accelerate them to warp speed—almost the speed of light—which make it pulse like a strobe light in space. Electrons gone wild are also evidence of the white dwarf spinning like a demon. Whether they actually come from the red dragon or the white phantom is still unexplained. The closest thing to we have to compare this electron-blasting star to is a pulsing neutron star (aka pulsar). Pulsars are also intensely magnetic, rotate ridiculously fast, and spew fiery blasts of electromagnetic radiation like Godzilla.

 While scientists have theorized that white dwarves could behave like neutron stars and possibly get as incensed as the hotter half of AR Scorpii, that still doesn’t illuminate where exactly its onslaught of electrons is coming from. Until the binary star is thoroughly investigated, the misbehavior remains a mystery.

(Via Sci News)

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