Planet's Giant Ring System

Astronomers have detected the first exoplanet (J1407b) with an extensive ring system similar to Saturn but about 200 times larger than those of our own ringed planet, possibly a young planetary system in an early transient phase of satellite formation.

Gaseous Earth-Mass Exoplanet

The recent discovery of an exoplanet (KOI-314c) with a mass comparable to Earth yet covered with a thick atmosphere of hydrogen and helium like a gas giant challenges theories on planetary formation and the assumption that Earth-mass planets necessarily be of a rocky composition.

Rogue Planet Spotted

Astronomers have visually spotted a so-called "rogue planet" (designated CFBDSIR2149-0403), a planet moving through interstellar space and not orbiting a star, just 100 light years distant.

Closest Earth-Sized Planet

Astronomers have confirmed the discovery of a planet only 1.1 times Earth's mass in orbit around the nearby star Alpha Centauri B just 4.4. light years away, unlikely to be habitable due to its orbit but likely the closest possible planet outside our own solar system.

New Class of Planet

Observations of the exoplanet GJ 1214b by the Hubble Space Telescope have revealed a newly discovered class of planet, one larger than Earth but with its mass consisting of more water than solid rock and an internal structure extraordinarily different than what is known.

First Habitable Planet Found

NASA's Kepler satellite has identified its first planet (Kepler-22b) existing within the so-called "habitable zone," an orbit around a star with conditions where liquid water could exist and therefore the possibility of life.

Billions of Planets Adrift

New data from gravitational microlensing observations estimates there are two Jupiter-mass or larger exoplanets adrift between star systems for every one of the 200 billion stars in the Milky Way galaxy, either ejected from their original planetary systems or stars that failed to form.

Smallest Rocky Exoplanet Found

Astronomers have discovered the smallest exoplanet yet found, a rocky world named Kepler 10b, 560 light years distant with a diameter about 1.4 times that of Earth and about 4.6 times greater mass but that orbits its star too closely to provide an environment suitable for life.

Rich Exoplanet System

Astronomers have found the richest system of planets outside our own solar system yet discovered orbiting the star HD 10180, with five "Neptune-like" exoplanets orbiting close to the star in near-circular orbits and possibly another two smaller planets found in unconfirmed "fuzzier" signals.

Planet with Comet-Like Tail

The Hubble Space Telescope has discovered an exoplanet (HD209458b) orbiting so close to its parent star that its heated atmosphere is escaping into space, with stellar winds providing the planet with a comet-like tail.

New Planet-Finding Technique

A team of astronomers has developed a new technique called transit timing variation (TTV) for detecting extrasolar planets as small as Earth, comparing the deviations from predictions of the transits of larger planets to determine the makeup of the star's planetary system.

First Directly Imaged Planet

A team using high-resolution adaptive optics at the Gemini Observatory has directly imaged a planet for the first time, the planet being about eight times the mass of Jupiter orbiting the sun-like star 1RXS 1609, and confirming their initial imaging work of 2008.

Planet-Eating Star

The Hubble Space Telescope has captured evidence of a star "eating" one of its orbiting planets (Wasp-12b), with the planet's atmosphere ballooning due to its proximity and a cloud of material escaping and captured by the nearby dwarf star.

Water-Rich "Super -Earth"

Astronomers have discovered a new rocky planet (GJ 1214b, dubbed "super Earth") that is only 2.7 times the mass of the Earth and likely to consist of at least half water by mass, albeit at temperatures and pressures to extreme to support life as we know it.

Chaotic Planetary System

NASA's Spitzer Space Telescope has imaged a three-body planetary system surrounding the star HR 8799 that shows evidence of a cloud of fine dust kicked up by collisions among smaller bodies, possibly showing a system still in formation with planets yet to have settled into stable orbits.

32 New Extrasolar Planets

Astronomers from the European Southern Observatory have announced the discovery of 32 new extrasolar planets, bringing the total number of known planets existing outside our solar system to over 400.

Rocky Planet Discovered

Astronomers have identified the first rocky extrasolar planet only slightly larger than the Earth, designated Corot-7b and about 500 light-years distant, albeit with a surface temperature around 3600°F.

New Planet Orbits Backwards

A newly discovered planet orbits the wrong way compared to its parent star in what is known as a retrograde orbit, possibly the result of an ancient near-collision with another object.

New Planet Discovered

A new exoplanet at least seven times as large as Jupiter has been discovered using new techniques to analyze Hubble Space Telescope data taken 11 years ago.

Orbiting Telescope Detects Smallest Exoplanet

An orbiting telescope run by the French space agency Centre National d’Etudes Spatiales (CNES) has detected the smallest exoplanet yet discovered, a planet only about twice the size of Earth.

The Corot telescope discovered the planet using a technique known as the transit method, by which the light of the star dims slightly as the planet crosses its visible path. Designated Corot-Exo-7b, the planet orbits its star once every 20 hours and because of its proximity to its sun, its surface temperature lies between 1000°C and 1500°C, far too inhospitable to support life. Another planet also orbits the same star, one larger and more similar to Neptune.

About 330 exoplanets have been identified so far, with most belonging to the type known as gas giants more similar to Jupiter or Neptune than "rocky" planets such as Earth or Mars. Most exoplanets are discovered using what is known as the radial velocity method, which is a slight but detectable wobbling of the star due to an orbiting planet's own gravity.

These results were announced February 3rd on the European Space Ageny (ESA) website.

Source: BBC News