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




EXO WORLDS
Weird Orbits Of Neighbors Can Make 'Habitable' Planets Not So Habitable
by Staff Writers
Seattle WA (SPX) May 27, 2010


An exoplanet with a mass similar to that of Jupiter but with a highly elliptical orbit could have dramatic effects on the orbit of a planet in the same system comparable to Earth, possibly even determining whether the smaller planet is habitable. Credit: NASA

Astronomers hunting for planets orbiting nearby stars similar to the sun are looking for signs of rocky, Earth-like planets in a "habitable" zone, where conditions such as temperature and liquid water remain stable enough to support life.

New findings from computer modeling indicate that some of those exoplanets might fluctuate between being habitable and being inhospitable to life because of the forces exerted by giant neighbors with eccentric orbits.

A lone Earth-like, or terrestrial, planet with a generally circular orbit toward the inner edge of its sun's habitable zone could be expected to remain within that zone, said Rory Barnes, a University of Washington postdoctoral researcher in astronomy. Adding a planet comparable to Jupiter to the system, however, and giving it a highly elliptical orbit - similar to most exoplanets discovered so far - can cause strange things to happen to the smaller planet, possibly causing it to cycle between habitable and uninhabitable conditions.

The smaller planet's orbit will elongate and then become more circular again, all in as little as 1,000 years, and could do so repeatedly. That raises the possibility, for example, that its average yearly temperature could change significantly during each millennium.

"For part of the time liquid water could exist on the surface, but at others it would boil off," said Barnes, who will present the findings Wednesday at a meeting of the American Astronomical Society in Miami.

The effect would be similar for an Earth-like planet at the outer edge of its habitable zone, except that its altered orbit likely would, at times, take it too far from its star, possibly resulting in planetary glaciation.

"The bigger issue here is that the habitable zone is very complicated," Barnes said. "Earth's climate is affected slightly over tens of thousands of years by the orbits of other planets in the solar system, but it is possible that in many exoplanetary systems the layout of the planets is very important to habitability."

The problem becomes even more complex for what could be habitable planets orbiting low-mass stars, perhaps one-third the mass of the sun. In such systems, the habitable zone is much closer to the smaller star, and tidal forces from the star's gravity are critical in determining whether the planet is habitable. Adding an eccentric orbit of a Jupiter-like planet could greatly alter conditions on the smaller planet as its orbit changes.

"There could be planets out there that have their geological properties change over very long timescales," Barnes said. "You can imagine planets that cycle in and out of intense volcanism and earthquake stages."

Tidal forces also fix the planet's rotation period, and as the orbit becomes more elongated the length of day can change significantly, Barnes said.

"The length of the day changes almost day to day," he said. "It's fascinating to think about how evolution occurs on such a world."

The work, funded by NASA's Virtual Planetary Laboratory, was conducted with Brian Jackson of NASA's Goddard Space Flight Center, Richard Greenberg of the University of Arizona and Sean Raymond of the Laboratoire d'Astrophysique de Bordeaux in France.

"There is this crazy zoo of planets out there that probably are habitable," Barnes said, "but their properties are very different from Earth and they're different from Earth because of their eccentric neighbors."

.


Related Links
University of Washington
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
Get It While it's Hot! Star Devours Planet
Moffett Field CA (SPX) May 26, 2010
The hottest known planet in the Milky Way galaxy may also be its shortest-lived world. The doomed planet is being eaten by its parent star, according to observations made by a new instrument on NASA's Hubble Space Telescope, the Cosmic Origins Spectrograph (COS). The planet may only have another 10,000 years left before it is completely devoured. The planet, called WASP-12b, is so close to ... read more


EXO WORLDS
Japan Draws Plans To Build Research Center On Moon

Caterpillar Participates In Inaugural Lunabotics Mining Competition

Loral Announces Milestone in NASA Ames Project

Einstein And Einstein A: A Study In Crater Morphology

EXO WORLDS
NASA Orbiter Penetrates Mysteries Of Martian Ice Cap

New INL Invention Could Aid Mars Probes' Search For Life

Phoenix Crushed By Frost

Opportunity Recharging Between Drives

EXO WORLDS
Tickling The Feet Of Astronauts

Committee Reviews Proposed Human Spaceflight Plan

Indian Space Programmes Serve Societal Needs

NASA Fixes Bug On Voyager 2

EXO WORLDS
Seven More For Shenzhou

China Signs Up First Female Astronauts

China To Launch Second Lunar Probe This Year

China, Bolivia to build communications satellite

EXO WORLDS
STS-132 Crew Completes Inspection And Prepare For Landing

Crews Opening Rassvet Hatches And Prepares For Spacewalk

Atlantis astronaut complete final spacewalk

Atlantis astronauts complete second spacewalk

EXO WORLDS
Ariane 5 Makes History With The ASTRA 3B And COMSATBw-2 Mission

Ariane 5 Is Poised For Launch With ASTRA 3B And COMSATBw-2

H2A Launches Six Satellites

Sea Launch Files Plan Of Reorganization

EXO WORLDS
Weird Orbits Of Neighbors Can Make 'Habitable' Planets Not So Habitable

Get It While it's Hot! Star Devours Planet

Exoplanetary System Offers Clues To Disturbed Past

Planet discovered lacking methane

EXO WORLDS
Dell, HP look into suicides at Foxconn China plant

Sony to challenge Apple in Japan with e-reader

Sony develops roll-up video screen

Apple iPad to make international debut on Friday




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