A new planet has been found orbiting three suns, meaning inhabitants would have to either experience constant daylight or "triple sunrises and sunsets every day" depending on the seasons – which last longer than the human lifespan.
HD 131399Ab, which was discovered by a team of astronomers led by the University of Arizona, is "unlike any other known world". The planet lies 340 light years from Earth and is around 16 million years old, making it one of the youngest exoplanets yet discovered.
The planet, known as HD 131399Ab, has a temperature of around 850 Kelvin – also making it one of the coldest exoplanets – and has four times the mass of Jupiter.
"HD 131399Ab is one of the few exoplanets that have been directly imaged, and it's the first one in such an interesting dynamical configuration," said Daniel Apai, an assistant professor of Astronomy and Planetary Sciences at the University of Arizona who led the research.
"For about half of the planet's orbit, which lasts 550 Earth-years, three stars are visible in the sky, the fainter two always much closer together, and changing in apparent separation from the brightest star throughout the year," he continued.
This means the planet has a 'night-side' and a 'day-side', with a triple sunrise and sunset each day.
And as the planet moves away from the stars during its orbit, it reaches a point where the setting of one star coincides with the rising of the other – a daytime that lasts 140 Earth-years.
It's the first planet identified with Sphere (Spectro-Polarimetric High-Contrast Exoplanet Research Instrument), an advanced instrument "dedicated to finding planets around other stars".
"It is not clear how this planet ended up on its wide orbit in this extreme system," said Apai. "And we can't say yet what this means for our broader understanding of the types of planetary systems out there, but it shows there is more variety out there than many would have deemed possible.
"What we do know is that planets in multi-star systems are much less explored, and potentially just as numerous as planets in single-star systems."
This article was originally published by WIRED UK
