HD 131399 Ab: The Planet With Three Suns That Shouldn’t Even Exist
June 7, 2017
The planet with three suns, named HD 131399 Ab (nicknamed Scorpion-1b), is four times as massive as Jupiter and orbits twice as far out as Pluto!
Three hundred and twenty light years away within the Centaurus constellation sits one of the strangest planets humans have ever set eyes on. It’s four times as large as Jupiter and orbits twice as far out as Pluto—around one amongst its 3 suns.
Using a new instrument at the European Southern Observatory’s very giant Telescope, a team of astronomers has noticed a planet in an exotic triple star system; it’s only the second such exoplanet well-known to science.
And in contrast to the first triple-star exoplanet—which orbits very near one star and extremely faraway from the other 2 — planet HD 131399 Ab is gravitationally influenced by all 3 suns.
Until now, astronomers weren’t certain such a planet might survive.
Exoplanet HD 131399 Ab, The Planet with three Suns
“I’d venture to say this is the weirdest orbit of any exoplanet we’ve ever found,” said Kevin Wagner, an astronomer at the University of Arizona and lead author on the study published in today’s Science. “We know of no other planet in a configuration like this.”
You can consider direct imaging like attempting to examine a firefly from a lighthouse 1,000 miles away—an extraordinarily tough thing to do.
The sole exoplanets we’ve imaged up to now are larger than Jupiter and sit in a comparable or wider orbit, where the glare of the parent star is not much intense.
But as our instruments have improved, so has our ability to examine a broader diversity of exoplanets. This includes some in multi-star systems that create the additional challenge of multiple sources of scattered light.
This Planet With Three Suns Shouldn’t Even Exist – Video By Gizmodo
History and Discovery
In 2014, the ESO’s very massive Telescope was outfitted with a brand new instrument referred to as SPHERE. This instrument features an accommodating optics system for canceling out the distortion of Earth’s atmosphere, as well as an instrument to block light, referred to as a coronagraph.
The SPHERE is currently one of the foremost powerful direct imaging tools planet hunters have at their disposal. And it bagged this exotic triple-star exoplanet on its very initial observational campaign.
HD 131399 Ab orbits a young A-type star, HD 131399 A, taking about 550 Earth years to finish one rotation.
Way on the far side of its orbit, a Sun-like star and a K-dwarf (predictably named B and C) twirl about each other like dumbbells, and at the same time both revolving slowly around star A.
“The planet is about a third of a way out [between star A, and the B/C pair],” Wagner said. “All of the stars have a lot of gravitational influence on the planet, meaning it has a very irregular orbit that’s constantly evolving and changing.”
Whether the competitive attractive tug of 3 stars will cause the world to be ripped apart or ejected from its overcrowded birthplace remains to be seen.
In cosmic terms, HD 131399 Ab is a baby, simply sixteen million years old. However the very fact that it’s survived this long suggests there may well be additional worlds like it.
Some may even be little, rocky, and livable!
It lies 80 AU from star A. While the binary pair B/C lies in a more distant orbit, also around star A. Image: ESO/K. Wagner et al.
“We thought that [triple star planets] weren’t going to be common, or at least in this extreme configuration, so we hadn’t really looked,” Wagner said. Studying these systems will expand our understanding of the conditions under which planets form and migrate about.
Wagner is continuing to refine HD 131399 Ab’s orbit to work out whether or not the world will be stable over the long-term.
However while the fate of triple star planets across the universe remains an issue mark, that shouldn’t stop us from imagining what life on such a world would be like.
“I like to start thinking about it from when the planet is opposite all three stars,” Wagner said. “When they aren’t eclipsing, you’d see three suns in the sky. As the planet with three suns progresses in its orbit, the stars will start to grow apart. This it will come to the point where the setting of one coincides with the rising of another.”
In essence on HD 131399 Ab you would have 2 seasons: one with 3 sunrises and sunsets each day. And another of perpetual daylight, where a rising star (or stellar pair) is often there to interchange a setting one.
Now that would be a truly mesmerizing sight to behold.
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