Three suns can be seen from a super Jupiter known as HD 131399Ab, sitting 340 light years away from our own world. The planet orbits around its family of suns once every 550 Earth years, and a single season on the giant world is completed just once every 140 years.
Any aliens living near this planet would experience conditions ranging from constant sunlight to experiencing three sunrises and sunsets each "day."
"For much of the planet's year the stars appear close together, giving it a familiar night-side and day-side with a unique triple-sunset and sunrise each day. As the planet orbits and the stars grow further apart each day, they reach a point where the setting of one coincides with the rising of the other — at which point the planet is in near-constant daytime for about one-quarter of its orbit, or roughly 140 Earth-years," said Kevin Wagner, who discovered the massive world.
Astronomers measured the diameter of HD 131399Ab, finding the super Jupiter to be roughly four times as large as the largest planet in our solar system. The far-flung placement of the world from its parent star suggests this world may not stay in its orbit for long.
Super Jupiters have been seen in other stellar systems, and exoplanets have been found in triple star systems in the past. However, the distant orbit of HD 131399Ab took astronomers by surprise. The world is thought to be incredibly young by astronomical standards — just 16 million years old.
The planet was discovered by a first-year doctoral student in the astronomy department at the University of Arizona. The system is seen from Earth sitting in the constellation Centaurus.
Astronomers believe the system is composed of a central star, HD 131399A, possessing around 80 percent more mass than our own sun. Orbiting at a distance roughly 300 times greater than that between our own sun and the Earth are a pair of smaller stars. They spin around each other at a distant roughly equal to that between our own sun and Saturn.
The Spectro-Polarimetric High-Contrast Exoplanet Research Instrument (Sphere), one of the most advanced instruments ever designed to hunt for planets around other stars, was utilized to make the discovery. This is the first exoplanet found by astronomers using the new device, which detects infrared waves emitted by distant worlds. The instrument is connected to the Very Large Telescope (VLT) in Chile, managed by the European Southern Observatory (ESO).
Analysis of the strange conditions seen at HD 131399Ab was profiled in the journal Science.