Newly Discovered Planet HD 131399Ab Has Three Suns

Posted on July 7, 2016

A team of astronomers led by the University of Arizona (UA) have discovered a gas giant planet in a triple star system. HD 131399Ab is located in the constellation Centaurus about 340 light years from Earth. It also has the widest known orbit within a multi-star system.

The astronomers HD 131399Ab has a temperature of 850 Kelvin (about 1,070 degrees Fahrenheit or 580 degrees Celsius) and weighs an estimated four Jupiter masses. It is the first discovery of an exoplanet made with the Spectro-Polarimetric High-Contrast Exoplanet Research Instrument (SPHERE), part of the Very Large Telescope in Chile.

Kevin Wagner, a first-year PhD student at UA and lead author of the study, says in a statement, "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. 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."

A research paper on the findings was published in the journal, Science. Here is an artist's impression of the HD 131399 system:

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