An alien planet, four to five times larger than Jupiter, just 300 light years from Earth has been photographed for the first time. The photograph of HD 95086 b, taken by the European Southern Observatory (ESO) in Chile, was released to the public June 3.
This newly-discovered world is a gaseous planet much like Jupiter and Saturn, but larger. Although estimated to be between four and five times larger than Jupiter, it may be the least-massive planet ever photographed outside our solar system. HD95086 b is believed to have a surface temperature of around 1300 degrees Fahrenheit.
Directly photographing planets outside our solar system presents several challenges, not the least of which is that the light from the planet's local star drowns out light reflected from the planet. It's like trying to photograph a firefly next to a spotlight from 100 miles away. To do this, astronomers need to block out the light from the star in order to see the planet. This has only been successfully accomplished for about 15 extra-solar planets. More often, worlds outside our solar system are detected through indirect means, like gravitational tugging on a planet's parent star blocking part of the light of its sun as it orbits.
"Direct imaging of planets is an extremely challenging technique that requires the most advanced instruments, whether ground-based or in space. Only a few planets have been directly observed so far, making every single discovery an important milestone on the road to understanding giant planets and how they form," Julien Rameau, an astronomer at the Institute of Astrophysics and Planetology in France and lead author of the study, said.
In the case of HD 95086 b, astronomers were aided in taking their photograph by the great distance that the planet orbits from its parent star - 56 times as far as Earth does from the Sun, or about twice as far as Neptune.
"It either grew by assembling the rocks that form the solid core and then slowly accumulated gas from the environment to form the heavy atmosphere, or started forming from a gaseous clump that arose from gravitational instabilities in the disc. Interactions between the planet and the disc itself or with other planets may have also moved the planet from where it was born," Anne-Marie Lagrange, a team member, said in a statement.
HD 95086, the star around which the gas giant orbits, is young - just 10 to 17 million years old, according to astronomers. Compare that to an estimated age of five billion years for the Sun. It is also slightly more massive than our home star.
The research leading to the photograph will be published in Astrophysical Journal Letters.
