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.
For more information about Extrasolar planet, read the full article at
Wikipedia.
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News tagged with exoplanets
Exoplanet atmospheres detected from Earth for the first time
Jan 14, 2009 |
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(PhysOrg.com) -- Transiting exoplanets are routinely detected when they pass in front of their parent star as viewed from the Earth, which only happens by chance. The transit event causes a small drop in the ...
Odd discovery may help refine theories about how planets form
Jun 17, 2009 |
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An international team of researchers has found a planet around another star whose orbit is steeply tilted from the plane of the star's equator, a finding that contradicts some theories about how solar systems form.
World's fastest and most sensitive astronomical camera
Jun 18, 2009 |
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The next generation of instruments for ground-based telescopes took a leap forward with the development of a new ultra-fast camera that can take 1,500 finely exposed images per second even when observing extremely ...
Mass Loss Leaves Close-In Exoplanets Exposed to the Core
Apr 21, 2009 |
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(PhysOrg.com) -- An international team of scientists has found that giant exoplanets orbiting very close to their stars could lose a quarter of their mass during their lifetime. The team found that planets ...
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Brown dwarf pair mystifies astronomers
Dec 21, 2009 |
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(PhysOrg.com) -- Two brown dwarf-sized objects orbiting a giant old star show that planets may assemble around stars more quickly and efficiently than anyone thought possible, according to an international ...
A faint star orbiting the Big Dipper's Alcor discovered
Dec 10, 2009 |
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Next time you spy the Big Dipper, keep in mind that there is another star, invisible to the unaided eye, contributing to this constellation.
Team using Subaru Telescope makes major discovery
Dec 03, 2009 |
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An international team of scientists that includes an astronomer from Princeton University has made the first direct observation of a planet-like object orbiting a star similar to the sun.
3 Questions: Sara Seager on searching for Earth-like planets
Nov 23, 2009 |
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(PhysOrg.com) -- MIT planetary scientist Sara Seager has been studying exoplanets — planets circling stars other than the sun — for many years.
A faraway planet intrigues: Exoplanet with extremely tilted orbit raises new interest in stellar astronomy
Nov 12, 2009 |
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(PhysOrg.com) -- Two teams of astronomers have found a planet outside the solar system that might be orbiting backwards compared to its star's rotation, a discovery that could shed light on how unique the ...
Exoplanets Clue to Sun's Curious Chemistry
Nov 11, 2009 |
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(PhysOrg.com) -- A ground-breaking census of 500 stars, 70 of which are known to host planets, has successfully linked the long-standing "lithium mystery" observed in the Sun to the presence of planetary systems. ...
Detecting Life-Friendly Moons
Space & Earth / Space Exploration
Oct 26, 2009 |
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The search for life-friendly real estate around distant stars doesn't have to be limited to planets. New research shows that habitable exomoons can be detected with a new method using current technology.
Building Planet Earth
Oct 22, 2009 |
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A new study shows how rocky planets are formed from the manic swirl of gas and dust that surround a young star, and determines what chemical building blocks are used to construct the planets. Understanding ...
The CoRoT space mission: Early results
Oct 22, 2009 |
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Astronomy & Astrophysics is publishing a special issue this week dedicated to the early results of the CoRoT space mission. The CoRoT (Convection, Rotation & planetary Transits) satellite is a 30 centimeter space ...
Astronomers do it Again: Find Organic Molecules Around Gas Planet (w/ Video)
Oct 20, 2009 |
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(PhysOrg.com) -- Peering far beyond our solar system, NASA researchers have detected the basic chemistry for life in a second hot gas planet, advancing astronomers toward the goal of being able to characterize ...
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