The Athenaeum

Hubble Reveals New Class Of Extrasolar Planet

Observations by NASA's Hubble Space Telescope have come up with a new class of planet, a waterworld enshrouded by a thick, steamy atmosphere. It's smaller than Uranus but larger than Earth.

Zachory Berta of the Harvard-Smithsonian Center for Astrophysics (CfA) and colleagues made the observations of the planet GJ1214b.

"GJ1214b is like no planet we know of," Berta said. "A huge fraction of its mass is made up of water."

The ground-based MEarth Project, led by CfA's David Charbonneau, discovered GJ1214b in 2009. This super-Earth is about 2.7 times Earth's diameter and weighs almost seven times as much. It orbits a red-dwarf star every 38 hours at a distance of 1.3 million miles, giving it an estimated temperature of 450 degrees Fahrenheit.

In 2010, CfA scientist Jacob Bean and colleagues reported that they had measured the atmosphere of GJ1214b, finding it likely that it was composed mainly of water. However, their observations could also be explained by the presence of a planet-enshrouding haze in GJ1214b's atmosphere.

Berta and his co-authors used Hubble's Wide Field Camera 3 (WFC3) to study GJ1214b when it crossed in front of its host star. During such a transit, the star's light is filtered through the planet's atmosphere, giving clues to the mix of gases.

"We're using Hubble to measure the infrared color of sunset on this world," Berta explained.

Hazes are more transparent to infrared light than to visible light, so the Hubble observations help tell the difference between a steamy and a hazy atmosphere.

They found the spectrum of GJ1214b to be featureless over a wide range of wavelengths, or colors. The atmospheric model most consistent with the Hubble data is a dense atmosphere of water vapor.

"The Hubble measurements really tip the balance in favor of a steamy atmosphere," Berta said.

Since the planet's mass and size are known, astronomers can calculate the density, of only about 2 grams per cubic centimeter. Water has a density of 1 gram per cubic centimeter, while Earth's average density is 5.5 grams per cubic centimeter. This suggests that GJ1214b has much more water than Earth does, and much less rock.

As a result, the internal structure of GJ1214b would be an extraordinarily different world than our world.

"The high temperatures and high pressures would form exotic materials like 'hot ice' or 'superfluid water,' substances that are completely alien to our everyday experience," Berta said.

Theorists expect 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, where surface temperatures would be similar to Earth's. How long it lingered there is unknown.

GJ1214b is located in the direction of the constellation Ophiuchus, and just 40 light-years from Earth. Therefore, it's a prime candidate for study by the planned James Webb Space Telescope.

A paper reporting these results has been accepted for publication in The Astrophysical Journal and is available online.

CONTACT

Ray Villard
Space Telescope Science Institute, Baltimore, Md.
410-338-4514
villard@stsci.edu

David Aguilar / Christine Pulliam
Harvard-Smithsonian Center for Astrophysics, Cambridge, Mass.
617-495-7462 / 617-495-7463
daguilar@cfa.harvard.edu / cpulliam@cfa.harvard.edu

Zachory Berta
Harvard-Smithsonian Center for Astrophysics, Cambridge, Mass.
617-495-4484
zberta@cfa.harvard.edu

(courtesy of http://hubblesite.org)

 

 

-Maureen Lang

 

Mardi Gras Music from Beau Soleil & Queen Ida

 

Beau Soleil- Zydeco Gris Gris

http://www.youtube.com/watch?v=mvXGJ8eP1B0

 

Queen Ida & the Bon Temps Zydeco Band- Rosa Majeure

http://www.youtube.com/watch?v=7gHIscVQB84

 

Happy Mardi Gras, everyone!

 

 

-Maureen Lang

Lake Vostok: Largest Sub-Glacial Lake Ever Discovered

Artist's conception of the "Cryobot" and "Hydrobot."  Source

In 1996, Russian scientists were drilling ice core samples at Vostok Station in Antarctica. When they reached 3,623 meters (11,886 feet), they stopped because they couldn't figure out why the ice at such an extreme depth was so clean. After a series of tests using radar and seismic waves, it turned out that this ice was actually the uppermost region of the world's largest warm-water sub-glacial lake - a lake roughly the size of Lake Ontario. The lake is composed of fresh water and has been isolated beneath the glacier for somewhere between half a million and one million years.

Naturally, the first thing that came to the scientists' minds was that this lake could possibly be the most pristine liquid environment on Earth and could be full of living creatures and organisms that, due to isolation and adaptation, live nowhere else. Researchers tested the core samples taken close to the water and indeed found microbes that have never been found elsewhere.

But when the question of how to explore the lake came up, not long after its discovery, the Vostok scientists faced a serious dilemma. The lake is under immense pressure, and to breach the ice would have devastating consequences. Secondly, anything sent into this pristine environment would have to be as sterile as possible to avoid contamination.

In 1999, NASA approved funding for the development of a torpedo-like probe dubbed "Cryobot." Equipped with a heated tip, the probe was designed to slowly melt its way down through the glacier, unwinding communication cables as it went. As Cryobot ventured down, the water would refreeze behind and above it. Then, before it breached the ceiling of the lake, the probe was to decontaminate itself with a hydrogen peroxide bath. Once inside, Cryobot would release the remote-controlled "Hydrobot," a specially designed submersible vehicle equipped with a camera and other instruments, to explore the interior of the lake.

Despite promising tests, funding for the project was cut in 2003. One hope, however, is that due to the discovery that Mars also has sub-glacial lakes and that Jupiter's moon Europa may have them as well, the Cryobot project will be re-opened soon in order to test technology for future space missions.

UPDATE: As of February, 2012 Russian scientists report that they have successfully drilled to the surface of the lake and pierced the ice sheet, however many in the scientific world are concerned about their method, which entails using kerosene to keep the borehole open. The fear is that only taking samples from the top of the lake will be insufficient for proper analysis, making the possible contamination a large risk with little benefit. The concern is that a mere surface sample will tell scientists nothing regarding the depth of the lake, or anything about the sediment, which could hold vital information, and that the kerosene could compromise the samples and skew data.

Regardless, the lake has been reached, and the unconfirmed word is that there is possibility of a “fundamental scientific development”. The Russian team is battling intense weather conditions, and communication is inconsistent and unpredictable, so the scientific community and the rest of the world can do nothing but wait until contact is reestablished to find out what, after 20 years of drilling, lies beneath the ice.

(courtesy of atlasobscura.com)

 

 

-Maureen Lang