Extrasolar planet
hideAn extrasolar planet, or exoplanet, is a planet beyond our Solar System, orbiting a star other than our Sun. As of June 2009[update], 353 exoplanets are listed in the Extrasolar Planets Encyclopaedia. The vast majority have been detected through radial velocity observations and other indirect methods rather than actual imaging. Most announced exoplanets are massive gas giant planets thought to resemble Jupiter, but this is a selection effect (bias) due to limitations in detection technology. Projections based on recent detections of much smaller worlds suggest that lightweight, rocky planets will eventually be found to outnumber extrasolar gas giants.
Extrasolar planets became a subject of scientific investigation in the mid-19th century. Many astronomers supposed that such planets existed, but they had no way of knowing how common they were or how similar they might be to the planets of our Solar System. The first confirmed radial velocity detection was made in 1995, revealing a gas giant planet in a four-day orbit around the nearby G-type star 51 Pegasi. The frequency of detections has tended to increase on an annual basis since then. It is estimated that at least 10% of sun-like stars have planets, and the true proportion may be much higher. The discovery of extrasolar planets sharpens the question of whether some might support extraterrestrial life.
Currently Gliese 581 d, the fourth planet of the red dwarf star Gliese 581 (approximately 20 light years from Earth), appears to be the best example yet discovered of a possible terrestrial exoplanet that orbits within the habitable zone surrounding its star. Although initial measurements suggested that Gliese 581 d resided outside the so-called "Goldilocks Zone", additional measurements place it firmly within.
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News tagged with extrasolar planets
Discovery of a Retrograde or Highly Tilted Extrasolar Planet
Nov 18, 2009 |
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Astronomers have found that the extrasolar planet HAT-P-7b has a retrograde or highly tilted orbit. Studying such planets is important in understanding the diversity of planetary systems and assessing current ...
The Hot Saturn Exoplanet
Oct 02, 2009 |
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(PhysOrg.com) -- Of the roughly 350 known exoplanets (i.e., extrasolar planets), the one orbiting the star HD149026 is unique.
Planet Imager will enable telescopes to image extrasolar planets directly
Sep 29, 2009 |
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The best way to observe objects in solar systems is simply to look -- but distortions caused by Earth's atmosphere drown out much of the spectacle of space. To address this problem, Berkeley astronomer James ...
Scientists Develop New Method to Find Alien Oceans, Earth-like Planets (w/Videos)
May 26, 2009 |
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(PhysOrg.com) -- Since the early 1990s astronomers have discovered more than 300 planets orbiting stars other than our sun, nearly all of them gas giants like Jupiter. Powerful space telescopes, such as the ...
Missing planets attest to destructive power of stars' tides
Apr 27, 2009 |
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During the last two decades, astronomers have found hundreds of planets orbiting stars outside our solar system. New research indicates they might have found even more except for one thing - some planets have fallen into ...
Finding Twin Earths: Harder Than We Thought
Mar 20, 2009 |
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(PhysOrg.com) -- Does a twin Earth exist somewhere in our galaxy? Astronomers are getting closer and closer to finding an Earth-sized planet in an Earth-like orbit. NASA's Kepler spacecraft just launched to ...
Adventures in the 'Goldilocks zone'
Space & Earth / Space Exploration
Mar 12, 2009 |
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When NASA's Kepler telescope rocketed into the night sky last week, two Berkeley astronomers watching its fading contrail were hoping that the telescope will reveal Earth's — and humanity's — place in the ...
With March 6 Kepler launch, work begins for Berkeley astronomers
Space & Earth / Earth Sciences
Mar 04, 2009 |
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(PhysOrg.com) -- When NASA's Kepler telescope rockets into the night sky on Friday, March 6, from Cape Canaveral Air Force Station in Florida, two University of California, Berkeley, astronomers - key members ...
Astronomy's bright future
Mar 02, 2009 |
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To mark UNESCO's International Year of Astronomy (IYA2009), six leading astronomers from the UK, the US, Europe and Asia write in March's Physics World about the biggest challenges and opportunities facing international astron ...
Laser-sculpted optical devices for future giant telescopes
Feb 05, 2009 |
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Future telescopes, with mirrors half the size of a football field, will need special components to deal with the light they collect. Astronomers are turning to photonic devices that guide and manipulate light inside specially-designed ...
Brown Dwarfs Don't Hang Out With Stars
Jan 05, 2009 |
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(PhysOrg.com) -- Brown dwarfs, objects that are less massive than stars but larger than planets, just got more elusive, based on a study of 233 nearby multiple-star systems by NASA's Hubble Space Telescope. ...
Deep Impact Films Earth as an Alien World
Space & Earth / Space Exploration
Jul 18, 2008 |
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(PhysOrg.com) -- NASA's Deep Impact spacecraft has created a video of the moon transiting (passing in front of) Earth as seen from the spacecraft's point of view 31 million miles away. Scientists are using ...
