An exoplanet or extrasolar planet is a planet outside the Solar System. The first possible evidence of an exoplanet was noted in 1917 but was not then recognized as such. The first confirmation of the detection occurred in 1992. A different planet, first detected in 1988, was confirmed in 2003. According to statistics from the NASA Exoplanet Archive, As of 17 October 2024, there are 5,780 confirmed exoplanets in 4,314 planetary systems, with 969 systems having more than one planet. The James Webb Space Telescope (JWST) is expected to discover more exoplanets, and to give more insight into their traits, such as their composition, environmental conditions, and potential for life.
CoRoT was a space telescope mission which operated from 2006 to 2013. The mission's two objectives were to search for extrasolar planets with short orbital periods, particularly those of large terrestrial size, and to perform asteroseismology by measuring solar-like oscillations in stars. The mission was led by the French Space Agency (CNES) in conjunction with the European Space Agency (ESA) and other international partners.
61 Virginis is the Flamsteed designation of a G-type main-sequence star (G7V) slightly less massive than the Sun, located 27.8 light-years away in the constellation of Virgo. The composition of this star is nearly identical to the Sun.
Solar-type stars, solar analogs, and solar twins are stars that are particularly similar to the Sun. The stellar classification is a hierarchy with solar twin being most like the Sun followed by solar analog and then solar-type. Observations of these stars are important for understanding better the properties of the Sun in relation to other stars and the habitability of planets.
Any planet is an extremely faint light source compared to its parent star. For example, a star like the Sun is about a billion times as bright as the reflected light from any of the planets orbiting it. In addition to the intrinsic difficulty of detecting such a faint light source, the light from the parent star causes a glare that washes it out. For those reasons, very few of the exoplanets reported as of January 2024 have been observed directly, with even fewer being resolved from their host star.
CoRoT-4 is a yellow-white dwarf main-sequence star in the constellation Monoceros.
CoRoT-7b is an exoplanet orbiting the star CoRoT-7 in the constellation of Monoceros, 489 light-years from Earth. It was first detected photometrically by the French-led CoRoT mission and reported in February 2009. Until the announcement of Kepler-10b in January 2011, it was the smallest exoplanet to have its diameter measured, at 1.58 times that of the Earth and the first potential extrasolar terrestrial planet to be found. The exoplanet has a very short orbital period, revolving around its host star in about 20 hours.
CoRoT-1 is a yellow dwarf main sequence star similar to the Sun. The star is located approximately 2,510 light-years away in the constellation of Monoceros. The apparent magnitude of this star is 13.6, which means it is not visible to the naked eye; however, it can be seen through a medium-sized amateur telescope on a clear, dark night. The first exoplanet discovered in the course of the CoRoT mission orbits this star; it is considered to be a "hot Jupiter", and is approximately as massive as the planet Jupiter itself.
CoRoT-2 is a yellow dwarf main sequence star a little cooler than the Sun. This star is located approximately 700 light-years away in the constellation of Aquila. The apparent magnitude of this star is 12, which means it is not visible to the naked eye but can be seen with a medium-sized amateur telescope on a clear dark night.
CoRoT-7 is a binary star system made up of a late G-type star and a M-dwarf star that was discovered in 2021. The primary star has three exoplanets, including CoRoT-7b, an super-Earth exoplanet that is remarkable due to its extremely high temperature and very short orbital period, around 20 hours. It was the first exoplanet shown to be rocky. The system has the name CoRoT-7 after the CoRoT space telescope, which discovered the exoplanets around the star CoRoT-7A. The stellar system is 520 light-years from the Earth.
CoRoT-6 is a magnitude 13.9 star located in the Ophiuchus constellation.
Gliese 146 is a star with an orbiting exoplanet in the constellation Horologium. Gliese 146 is also catalogued as HD 22496, HIP 16711, SAO-216392, and LHS 1563. With an apparent visual magnitude of 8.64, it is too faint to be visible to the naked eye. Gliese 146 is located at a distance of 44.4 light years based on parallax measurements, and is drifting further away with a heliocentric radial velocity of +21 km/s.
HIP 11915 is a G-type main-sequence star located about 170 light-years from Earth in the constellation Cetus. It is best known for its characteristics, which are very similar to those of the Sun, including the mass, radius, temperature, metallicity and age, which means that it is almost a solar twin, being just 500 million years younger than the Sun and with a lower metallicity. It is also known for its planetary companion, HIP 11915 b, which has a mass and orbital distance very similar to that of Jupiter, but probably with a slightly higher orbital eccentricity.
CoRoT-16b is a transiting exoplanet orbiting the G or K type main sequence star CoRoT-16 2,433 light years away in the southern constellation Scutum. The planet was discovered in June 2011 by the French-led CoRoT mission.
CoRoT-23b is a transiting Hot Jupiter exoplanet found by the CoRoT space telescope in 2011.
HAT-P-23 is a G-type main-sequence star 1192 light-years away. It has a rapid rotation for its advanced age of 4 billion years, and exhibits a strong starspot activity. The star may be in the process of being spun up by the giant planet on close orbit. The star is enriched in heavy elements, having about 140% amount of metals compared to solar abundance.
HAT-P-21 is a G-type main-sequence star about 927 light-years away. The star has amount of metals similar to solar abundance. The survey in 2015 has failed to detect any stellar companions. The star is rotating rapidly, being spun up by the tides of giant planet on close orbit.
HAT-P-20 is a K-type main-sequence star about 233 light-years away. The star has a strong starspot activity, and its equatorial plane is misaligned by 36+10
−12° with the planetary orbit. Although star with a giant planet on close orbit is expected to be spun-up by tidal forces, only weak indications of tidal spin-up were detected.
HAT-P-16 is a F-type main-sequence star about 725 light-years away. The star has a concentration of heavy elements slightly higher than solar abundance, and low starspot activity. The survey in 2015 have failed to find any stellar companions to it. The spectral analysis in 2014 have discovered the HAT-P-16 has a carbon to oxygen molar ratio of 0.58±0.08, close to Sun`s value of 0.55.
HD 42618 is a well-studied star with an exoplanetary companion in the equatorial constellation of Orion. With an apparent visual magnitude of 6.85 it is too faint to be readily visible to the naked eye. This system is located at a distance of 79.6 light years from the Sun based on parallax measurements. It has a relatively high proper motion, traversing the celestial sphere at an angular rate of 0.321″ per year. HD 42618 is drifting closer with a radial velocity of −53.5 km/s and is predicted to come as near as 42.6 light-years in around 297,000 years.
