Exoplanets in the context of "HR 8799"

Paranal Observatory is an astronomical observatory operated by the European Southern Observatory (ESO). It is located in the Atacama Desert of Northern Chile on Cerro Paranal at 2,635 m (8,645 ft) altitude, 120 km (70 mi) south of Antofagasta. By total light-collecting area, it is the largest optical-infrared observatory in the Southern Hemisphere; worldwide, it is second to the Mauna Kea Observatory on Hawaii.

The Very Large Telescope (VLT), the largest telescope on Paranal, is composed of four separate 8.2 m (320 in) telescopes. In addition, the four main telescopes can be used simultaneously for extra light gathering capacity, and for interferometry. Four auxiliary telescopes of 1.8 m (71 in) each are also part of the VLTI to make it available when the main telescopes are being used for other projects. The site also houses two survey telescopes with wide fields of view, the 4.0 m (160 in) VISTA and the 2.6 m (100 in) VLT Survey Telescope for surveying large areas of the sky; and two arrays of small telescopes called NGTS and SPECULOOS which are dedicated to searching for exoplanets.

SPECULOOS (Search for habitable Planets EClipsing ULtra-cOOl Stars) is a project consisting of SPECULOOS Southern Observatory (SSO) at the Paranal Observatory in Chile and SPECULOOS Northern Observatory (SNO) at the Teide Observatory in Tenerife.

The SSO consists of four Ritchey–Chrétien telescopes of 1-metre primary aperture, made by ASTELCO. Each telescope is equipped with a NTM-1000 robotic mount and will search for Earth-sized exoplanets around 1000 ultra-cool stars and brown dwarfs. As of June 2019, the SNO consists of one telescope, but more might be added in the future with up to three telescopes for SNO. SPECULOOS is complemented by SAINT-EX and TRAPPIST.

Kepler-7b is one of the first five exoplanets to be confirmed by NASA's Kepler spacecraft, and was confirmed during the first 34 days of Kepler's science operations. It orbits a star slightly hotter and significantly larger than the Sun that is expected to soon reach the end of the main sequence. Kepler-7b is a hot Jupiter that is about half the mass of Jupiter, but is nearly 1.5 times its size; at the time of its discovery, Kepler-7b was the second most diffuse planet known, surpassed only by WASP-17b. It orbits its host star every five days at a distance of approximately 0.06 AU (9,000,000 km; 5,600,000 mi). Kepler-7b was announced at a meeting of the American Astronomical Society on January 4, 2010. It is the first extrasolar planet to have a crude map of cloud coverage.

Metallic hydrogen is a phase of hydrogen in which it behaves like an electrical conductor. This phase was predicted in 1935 on theoretical grounds by Eugene Wigner and Hillard Bell Huntington.

At high pressure and temperatures, metallic hydrogen can exist as a partial liquid rather than a solid. It is thought to appear in large quantities in the hot and gravitationally compressed interiors of Jupiter and Saturn, as well as in some exoplanets.

The Geneva Observatory (French: Observatoire de Genève, German: Observatorium von Genf) is an astronomical observatory at Sauverny (CH) in the municipality of Versoix, Canton of Geneva, in Switzerland. It shares its buildings with the astronomy department of the École Polytechnique Fédérale de Lausanne. It has been active in discovering exoplanets, in stellar photometry, modelling stellar evolution, and has been involved in the European Space Agency's Hipparcos, INTEGRAL, Gaia, and Planck missions.

In 1995, the first exoplanet found orbiting a main-sequence star, 51 Pegasi b, was discovered by two scientists of the observatory, Michel Mayor and Didier Queloz, using the radial velocity method with the 1.9-metre telescope at Haute-Provence Observatory in France. Mayor and Queloz were awarded (half of) the Nobel Prize in Physics 2019 for this discovery.

Planetary migration occurs when a planet or other body in orbit around a star interacts with a disk of gas or planetesimals, resulting in the alteration of its orbital parameters, especially its semi-major axis. Planetary migration is the most likely explanation for hot Jupiters (exoplanets with Jovian masses but orbits of only a few days). The generally accepted theory of planet formation from a protoplanetary disk predicts that such planets cannot form so close to their stars, as there is insufficient mass at such small radii and the temperature is too high to allow the formation of rocky or icy planetesimals.

It has also become clear that terrestrial-mass planets may be subject to rapid inward migration if they form while the gas disk is still present. This may affect the formation of the cores of the giant planets (which have masses of the order of 10 to 1000 Earth masses), if those planets form via the core-accretion mechanism.