The Planet:
Located about 340 light years from Earth in the constellation
Centaurus, HD 131399Ab is believed to be about 16 million years old,
making it one of the youngest exoplanets discovered so far (for
comparison, our Earth’s age is 4600 million years). The planet named
HD131399Ab is gaseous planet having four times the size of our
Jupiter planet. With a temperature of 850 kelvins (about 1,070 F or
580 C) and weighing in at an estimated four Jupiter masses, it is also
one of the coldest and least massive directly-imaged exoplanets.
"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," said Kevin Wagner, a doctoral student in Apai's
research group and the paper's first author, who discovered
HD131399Ab.
"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 farther 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."
The planet HD131399Ab is the first discovery of an exoplanet made
with SPHERE (Spectro-Polarimetric High-Contrast Exoplanet
Research Instrument). It is installed on the Very Large Telescope
operated by the European Southern Observatory on Cerro Paranal in
the Atacama Desert of northern Chile, and dedicated to finding
planets around other stars. SPHERE is sensitive to infrared light,
making it capable of detecting the heat signatures of young planets,
along with sophisticated features correcting for atmospheric
disturbances and blocking out the otherwise blinding light of their
host stars.
Friends of Scientifica,
October
2016