Featured Research

from universities, journals, and other organizations

New conditions for life on other planets: Tidal effects change 'habitable zone' concept

Date:
March 2, 2011
Source:
Astrophysikalisches Institut Potsdam
Summary:
Tides can render the so-called "habitable zone" around low-mass stars uninhabitable, according to new research. Until now, the two main drivers thought to determine a planet's temperature were the distance to the central star and the composition of the planet's atmosphere.

Artist's concept of a large, rocky extrasolar planet.
Credit: NASA/JPL-Caltech

Tides can render the so-called "habitable zone" around low-mass stars uninhabitable. This is the main result of a recently published study by a team of astronomers led by Renι Heller of the Astrophysical Institute Potsdam (AIP).

Related Articles


Extrasolar planets, or exoplanets for short, have been known to exist outside our solar system since 1995. When searching for life in outer space, scientists focus on those exoplanets that are located in the habitable zone. This means that they orbit their sun at a distance where the temperatures on the planet's surface allow for the presence of liquid water. Water is believed to be an essential ingredient for life. Until now, the two main drivers thought to determine a planet's temperature were the distance to the central star and the composition of the planet's atmosphere. By studying the tides caused by low-mass stars on their potential earth-like companions, Heller and his colleagues have concluded that tidal effects modify the traditional concept of the habitable zone.

Heller deduced this from three different effects. Firstly, tides can cause the axis of a planet`s rotation to become perpendicular to its orbit in just a few million years. In comparison, Earth's axis of rotation is inclined by 23.5 degrees -- an effect which causes our seasons. Owing to this effect, there would be no seasonal variation on such Earth-like planets in the habitable zone of low-mass stars. These planets would have huge temperature differences between their poles, which would be in perpetual deep freeze, and their hot equators which in the long run would evaporate any atmosphere. This temperature difference would cause extreme winds and storms.

The second effect of these tides would be to heat up the exoplanet, similar to the tidal heating of Io, a moon of Jupiter that shows global vulcanism.

Finally, tides can cause the rotational period of the planet (the planet's "day") to synchronize with the orbital period (the planet's "year"). This situation is identical to the Earth-moon setup: the moon only shows Earth one face, the other side being known as "the dark side of the moon." As a result one half of the exoplanet receives extreme radiation from the star while the other half freezes in eternal darkness.

The habitable zone around low-mass stars is therefore not very comfortable -- it may even be uninhabitable. From an observer's point of view, low-mass stars have so far been the most promising candidates for habitable exoplanets. Now, due to Heller's findings, Earth-like exoplanets that have already been found in the conventional habitable zone of low-mass stars, have to be re-examined to consider tidal effects.

Heller and his colleagues have applied their theory to GI581g: an exoplanet candidate that has recently been claimed to be habitable. They find that GI581g should not experience any seasons and that its day is synchronized with its year. There probably would be no water on the planet's surface, rendering it uninhabitable.

Heller said, "I think that the chances for life existing on exoplanets in the traditional habitable zone around low-mass stars are pretty bleak, when considering tidal effects. If you want to find a second Earth, it seems that you need to look for a second Sun."


Story Source:

The above story is based on materials provided by Astrophysikalisches Institut Potsdam. Note: Materials may be edited for content and length.


Journal Reference:

  1. R. Heller, J. Leconte, R. Barnes. Tidal obliquity evolution of potentially habitable planets. Astronomy & Astrophysics, 2011; 528: A27 DOI: 10.1051/0004-6361/201015809

Cite This Page:

Astrophysikalisches Institut Potsdam. "New conditions for life on other planets: Tidal effects change 'habitable zone' concept." ScienceDaily. ScienceDaily, 2 March 2011. <www.sciencedaily.com/releases/2011/02/110224091735.htm>.
Astrophysikalisches Institut Potsdam. (2011, March 2). New conditions for life on other planets: Tidal effects change 'habitable zone' concept. ScienceDaily. Retrieved January 29, 2015 from www.sciencedaily.com/releases/2011/02/110224091735.htm
Astrophysikalisches Institut Potsdam. "New conditions for life on other planets: Tidal effects change 'habitable zone' concept." ScienceDaily. www.sciencedaily.com/releases/2011/02/110224091735.htm (accessed January 29, 2015).

Share This


More From ScienceDaily



More Space & Time News

Thursday, January 29, 2015

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Asteroid's Moon Spotted During Earth Flyby

Asteroid's Moon Spotted During Earth Flyby

Rumble (Jan. 27, 2015) — Scientists working with NASA&apos;s Deep Space Network antenna at Goldstone, California discovered an unexpected moon while observing asteroid 2004 BL86 during its recent flyby past Earth. Credit to &apos;NASA JPL&apos;. Video provided by Rumble
Powered by NewsLook.com
Water Fleas Prepare for Space Voyage

Water Fleas Prepare for Space Voyage

Reuters - Innovations Video Online (Jan. 26, 2015) — Scientists are preparing a group of water fleas for a unique voyage into space. The aquatic crustaceans, known as Daphnia, can be used as a miniature model for biomedical research, and their reproductive and swimming behaviour will be tested for signs of stress while on board the International Space Station. Jim Drury went to meet the team. Video provided by Reuters
Powered by NewsLook.com
Mars Rover Opportunity Celebrates 11-Year Anniversary

Mars Rover Opportunity Celebrates 11-Year Anniversary

Rumble (Jan. 26, 2015) — Eleven years ago NASA&apos;s Opportunity rover touched down on Mars for what was only supposed to be a 90-day mission. Since then it has traveled 25.9 miles (41.7 kilometers), further than any other off-Earth surface vehicle has ever driven. Credit to &apos;NASA&apos;. Video provided by Rumble
Powered by NewsLook.com
NASA's On Course To Take Pluto's Best Photo Ever

NASA's On Course To Take Pluto's Best Photo Ever

Newsy (Jan. 25, 2015) — NASA&apos;s New Horizons probe is en route to snap a picture of Pluto this summer, but making sure it doesn&apos;t miss its one chance to do so starts now. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:

Strange & Offbeat Stories

 

Space & Time

Matter & Energy

Computers & Math

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:  

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile iPhone Android Web
Follow Facebook Twitter Google+
Subscribe RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins