Calling Kevin Costner. Don't tell BP. Astronomers at the Harvard-Smithsonian Center for Astrophysics (CfA) have come up with a new class of planet, described as "a waterworld enshroded by a thick, steamy atmosphere." You might call it a sequel to the original discovery of the exoplanet, called GJ1214b.
NASA explains that GJ1214b is smaller than Uranus (the planet), but larger than Earth. Too bad it's 40 light-years away. Or maybe that's a blessing (for the planet). This new planet likely has much more water than Earth, experts say, and much less rock. The "waterworld" finding was made by astronomer Zachory Berta and colleagues from the Harvard-Smithsonian CfA, using the Hubble Space Telescope.
The image at top is a new artist's view of GJ1214b, described further as a super-Earth orbiting a red dwarf star.
The planet's atmosphere was measured in 2010 by CfA scientist Jacob Bean and colleagues, who said at the time that it was probably composed mostly of water. Back then, as shown below, the planet was envisioned as having two moons.
The latest finding, that this is indeed a waterworld (kind of like the 1995 Costner movie) came after Berta and colleagues used Hubble instruments to study GJ1214b when it crossed in front of a host star.
"During such a transit, the star's light is filtered through the planet's atmosphere, giving clues to the mix of gases," Harvard officials explain.
"We're using Hubble to measure the infrared color of sunset on this world," says Berta.
It's believed that "GJ1214b formed farther out from its star, where water ice was plentiful, and migrated inward early in the system's history. In the process, it would have passed through the star's habitable zone. How long it lingered there is unknown."
NASA says this planet is like nothing seen before, in our solar system or any other. GJ1214b is located near the constellation Ophiuchus (the 13th sign of the zodiac).
Officials say we'll be hearing more about this new waterworld in years to come, as its location makes it a prime candidate for study by the next-generation James Webb Space Telescope.
A paper reporting the waterworld results by Berta and others has been published in The Astrophysical Journal.
A little farther out, a view of the global cluster Messier 12 in the constellation of Ophiuchus.