Astronomers have directly imaged a “super-Jupiter” planet orbiting around the star Kappa Andromedae.
According to NASA, Kappa Andromedae now holds the record for the most massive star to host a directly imaged planet or lightweight brown dwarf companion. The planet, designated Kappa Andromedae b (Kappa And b), has a mass 12.8 times greater than Jupiter’s, making it almost a low-mass brown dwarf.
“According to conventional models of planetary formation, Kappa And b falls just shy of being able to generate energy by fusion, at which point it would be considered a brown dwarf rather than a planet,” said Michael McElwain, a member of the discovery team at NASA’s Goddard Space Flight Center. “But this isn’t definitive, and other considerations could nudge the object across the line into brown dwarf territory.”
The mass necessary for an object to be considered a brown dwarf is around 13 times the mass of Jupiter. At that point, the object is massive enough for deuterium (a heavy isotope of hydrogen) fusion to begin.
Kappa And b was imaged using infrared data from the Subaru Telescope in Mauna Kea, Hawaii. The research is part of the Strategic Explorations of Exoplanets and Disks with Subaru (SEEDS) project, which images extrasolar planets and protoplanetary disks around nearby stars. Researchers project images at near-infrared wavelengths using the Subaru Telescope’s adaptive optics system.
Kappa Andromedae is a massive star that is only 30 million years old. The B9-type star is located 170 light-years from the solar system and is visible with the naked eye near the constellation Andromeda. Kappa And b has a temperature of around 1,400 degrees Celsius (2,600 degrees Fahrenheit) and orbits Kappa Andromedae at around 55 times the Earth’s distance from the Sun. A paper describing the SEEDS team’s observations of the objects is set to be published in The Astrophysical Journal Letters.