Subscribe free to our newsletters via your
. 24/7 Space News .




EXO WORLDS
Most Earth-Like Exoplanet Started Out As A Gas Giant
by Staff Writers
Washington DC (SPX) Jan 07, 2010


"CoRoT-7b may be the first in a new class of planet- evaporated remnant cores," Jackson said. "Studying the coupled processes of mass loss and migration may be crucial to unraveling the origins of the hundreds of hot, earthlike planets space missions like CoRoT and NASA's Kepler will soon uncover."

The most Earth-like planet yet found around another star may be the rocky remains of a Saturn-size gas giant, according to research presented at the American Astronomical Society meeting in Washington, DC.

"The first planets detected outside our solar system 15 years ago turned out to be enormous gas giants in very tight orbits around their stars. We call them 'hot Jupiters,' and they weren't what astronomers expected to find," said Brian Jackson at NASA's Goddard Space Flight Center in Greenbelt, Md. "Now, we're beginning to see Earth-size objects in similar orbits. Could there be a connection?"

Jackson and his colleagues turned to CoRoT-7b, the smallest planet and the most like Earth that astronomers have found to date. Discovered in February 2009 by the Convection, Rotation and Planetary Transits (CoRoT) satellite, a mission led by the French Space Agency, CoRoT-7b takes just 20.4 hours to circle its Sun-like star, located 480 light-years away in the constellation Monoceros. Astronomers believe the star is about 1.5 billion years old, or about one-third the Sun's age.

"CoRoT-7b is almost 60 times closer to its star than Earth, so the star appears almost 360 times larger than the Sun does in our sky," Jackson said. As a consequence, the planet's surface experiences extreme heating that may reach 3,600 degrees Fahrenheit on the daylight side. CoRoT-7b's size (70 percent larger than Earth) and mass (4.8 times Earth's) indicate that the world is probably made of rocky materials.

"But with such a high dayside temperature, any rocky surface facing the star must be molten, and the planet cannot retain anything more than a tenuous atmosphere, even one of vaporized rock," Jackson said. He estimates that solar heating may have already cooked off several Earth masses of material from CoRoT-7b.

With the help of computer models that track the planet's mass loss and orbital changes, the researchers have turned back the planet's clock.

"There's a complex interplay between the mass the planet loses and its gravitational pull, which raises tides on the star," Jackson explained. Those tides gradually change the planet's orbit, drawing it inward in a process called tidal migration. But closer proximity to the star then increases the mass loss, which in turn slows the rate of orbital change.

After accounting for the give-and-take of mass loss and tidal migration, the team finds that CoRot-7b could have weighed in at 100 Earth masses- or about the heft of Saturn- when it first formed. At that time, it orbited 50 percent farther from its star than it does now.

The researchers also show that regardless of whether CoRot-7b started life as a Saturn-like gas giant or as a rocky world, the planet has probably lost many Earth masses of material since its formation.

"You could say that, one way or the other, this planet is disappearing before our eyes," Jackson said.

He suggests that similar processes likely have influenced many other exoplanets that lie close to their stars. In fact, several recent studies suggest that many hot Jupiters have undergone similar mass loss and tidal evolution, perhaps leaving behind remnant cores similar to CoRoT-7b.

"CoRoT-7b may be the first in a new class of planet- evaporated remnant cores," Jackson said. "Studying the coupled processes of mass loss and migration may be crucial to unraveling the origins of the hundreds of hot, earthlike planets space missions like CoRoT and NASA's Kepler will soon uncover."

The research team also includes Neil Miller and Jonathan Fortney at the University of California, Santa Cruz; Rory Barnes at the University of Washington's Virtual Planet Lab in Seattle; Sean Raymond at the Astrophysical Laboratory of Bordeaux, France; and Richard Greenberg at the University of Arizona, Lunar and Planetary Lab, in Tucson.

.


Related Links
the missing link Lands Beyond Beyond - extra solar planets - news and science
Life Beyond Earth






Comment on this article via your Facebook, Yahoo, AOL, Hotmail login.

Share this article via these popular social media networks
del.icio.usdel.icio.us DiggDigg RedditReddit GoogleGoogle




Memory Foam Mattress Review
Newsletters :: SpaceDaily :: SpaceWar :: TerraDaily :: Energy Daily
XML Feeds :: Space News :: Earth News :: War News :: Solar Energy News





EXO WORLDS
Earth-Like Planet Probably A Wasteland
Washington DC (SPX) Jan 06, 2010
When scientists confirmed in October that they had detected the first rocky planet outside our solar system, it advanced the longtime quest to find an Earth-like planet hospitable to life. Rocky planets - Earth, Mercury, Venus and Mars - make up half the planets in our solar system. Rocky planets are considered better environments to support life than planets that are mainly gaseous, like ... read more


EXO WORLDS
Space Systems Loral To Supply Lunar Mission Propulsion System

Lava tube could house moon colony

Moon Mission In Running For Next Big Space Venture

Obama cuts moon travel, links NASA to private firms

EXO WORLDS
Minimal Progress In Recent Extraction Drives

Goddard Scientist Breakthrough Given Ticket To Mars

Mars Spirit Rover Facing End Of Mission Decision

Mars rover Spirit's 6-year stint may be ending: NASA

EXO WORLDS
Galactic GPS Possible With Pulsars And Gravity Waves

US still has space ambitions: NASA chief

Chairman Gordon Comments On President's Budget Request

South Korea to send its cuisine into space

EXO WORLDS
China Building Large Radio Telescope For Space Observation

China To Launch Civil HD Survey Satellite In 2011

China Launches First Public-Welfare Mini Satellite

Chang'e-1 Has Blazed A New Trail In China's Deep Space Exploration

EXO WORLDS
How To Live Long And Prosper In Space

Russia Set To Launch Another Space Truck To ISS

Obama budget extends US commitment to space station

Mini-Research Module MRM1 At Cape For Shuttle Processing

EXO WORLDS
Arianespace Poised For 2010 Boost

Booz Allen Hamilton To Transform LA Spacelift Range

Apron Construction Contract Awarded For Spaceport America

Shuttle-Derived Vehicle: Shuttle-Derived Disaster

EXO WORLDS
Massive Stars Easy Targets For Planet Hunters

Most Earth-Like Exoplanet Started Out As A Gas Giant

Sun Glints Seen From Space Signal Oceans And Lakes

NASA's Kepler space telescope finds five new exoplanets

EXO WORLDS
Toshiba TV adds third dimension to video viewing

Blockbuster 'Avatar' to accelerate 3D revolution

Y2X bugs strikes 30 million German credit cards

Superatom mimicry offers insights to periodic table




The content herein, unless otherwise known to be public domain, are Copyright 1995-2014 - Space Media Network. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA Portal Reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. Advertising does not imply endorsement,agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. Privacy Statement