Related topics: orbit · stars · planets · solar system

Astronomers detect possible radio emission from exoplanet

By monitoring the cosmos with a radio telescope array, a Cornell University-led international team of scientists has detected radio bursts emanating from the constellation Boötes. The signal could be the first radio emission ...

Earth-like planet around Proxima Centauri discovered

The hunt for exoplanets has been heating up in recent years. Since it began its mission in 2009, over four thousand exoplanet candidates have been discovered by the Kepler mission, several hundred of which have been confirmed ...

Scientists find potentially habitable planet near Earth

(PhysOrg.com) -- A team of planet hunters led by astronomers at the University of California, Santa Cruz, and the Carnegie Institution of Washington has announced the discovery of an Earth-sized planet (three times the mass ...

Worldwide observations confirm nearby 'lensing' exoplanet

Researchers using telescopes around the world confirmed and characterized an exoplanet orbiting a nearby star through a rare phenomenon known as gravitational microlensing. The exoplanet has a mass similar to Neptune, but ...

Analysis of the First Kepler SETI Observations

As the Kepler space telescope begins finding its first Earth-sized exoplanets, with the ultimate goal of finding ones that are actually Earth-like, it would seem natural that the SETI (Search for Extraterrestrial Intelligence) ...

Eighteen-hour-year planet on edge of destruction

Astronomers from the University of Warwick have observed an exoplanet orbiting a star in just over 18 hours, the shortest orbital period ever observed for a planet of its type.

page 1 from 40

Extrasolar planet

An 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.

This text uses material from Wikipedia, licensed under CC BY-SA