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An illustration of the magenta exoplanet, still glowing from the heat of its formation. Illustration courtesy S. Wiessinger, NASA
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There is a pink exoplanet circling a star very much like our own, 57 light-years away from Earth. But its origins are a mystery.
In a new study announcing the magenta gas giant, researchers were able to directly image this exoplanet using the Subaru telescope on Hawaii. The color of this blushing body indicates it has less cloud cover than other observed exoplanets, meaning researchers can peer even deeper into its atmosphere to divine its components.
"If we could travel to this giant planet, we would see a world still glowing from the heat of its formation with a color reminiscent of a dark cherry blossom, a dull magenta," said Michael McElwain, an astrophysicist at NASA's Goddard Space Flight Facility in Maryland and a study co-author, in a statement.
It's one of only five or six exoplanets whose presence has been directly imagedby a telescope, rather than inferred from observing stars, said Markus Janson, an astrophysicist at Princeton University and a co-author of the new study.
Other planets that have been directly imaged orbit much more massive stars, he added. "In that sense, [the pink planet] feels a bit closer to home."
At about 460°F (237°C), this gas giant probably wouldn't be a very pleasant place to visit. But researchers are still interested in this lightweight—it's one of the lowest-mass exoplanets found around a sun-like star using direct detection methods.
Ejected
It orbits about 43 astronomical units (AUs) away from its parent star, much farther out than Neptune's orbit (30 AUs) around the sun.
In a mechanism called the core accretion model, bits of rock, dust, and ice in the disk of material around a young star collide and stick together until the solid lump grows to the size of a planet.
But this tends to happen close in to a star, said Janson. "Because [this planet] is so far out, it's very hard to see how it formed by core accretion."
But planet formation is an evolving field, and this is just one possible explanation, he added.
McElwain and colleagues would also like a better sense of this magenta giant's orbit.
Something 43 AUs from its star would take more than a hundred years to complete an orbit, McElwain said.
The shape of the exoplanet's orbit would also lend further clues as to its formation. If it's on a very eccentric—or non-circular—orbit, that would support the scattering hypothesis, McElwain said.
This is why it's important to get as complete a picture as possible on the types of exoplanets out there, said Adam Burrows, an astrophysicist at Princeton University and a study co-author.
Several telescopes coming online in the next year or two will be even better at picking up the faint glow given off by exoplanets, Burrows added.
Source : National Geographic.com
By Science and Universe