Astrometry is a branch of astronomy that involves precise measurements of the positions and movements of stars and other celestial bodies. It provides the kinematics and physical origin of the Solar System and this galaxy, the Milky Way.
HD 150706 is a star with an orbiting exoplanet in the northern constellation of Ursa Minor. It is located 92 light years away from the Sun, based on parallax measurements. At that distance, it is not visible to the unaided eye. However, with an apparent visual magnitude of 7.02, it is an easy target for binoculars. It is located only about 10° from the northern celestial pole so it is always visible in the northern hemisphere except for near the equator. Likewise, it is never visible in most of the southern hemisphere. The star is drifting closer to the Sun with a radial velocity of −17.2 km/s.
Rho Coronae Borealis is a yellow dwarf star 57.1 light-years away in the constellation of Corona Borealis. The star is thought to be similar to the Sun with nearly the same mass, radius, and luminosity. It is orbited by four known exoplanets.
2M1207b is a planetary-mass object orbiting the brown dwarf 2M1207, in the constellation Centaurus, approximately 170 light-years from Earth. It is one of the first candidate exoplanets to be directly observed. It was discovered in April 2004 by the Very Large Telescope (VLT) at the Paranal Observatory in Chile by a team from the European Southern Observatory led by Gaël Chauvin. It is believed to be from 5 to 6 times the mass of Jupiter and may orbit 2M1207 at a distance roughly as far from the brown dwarf as Pluto is from the Sun.
HD 38529 is a binary star approximately 138 light-years away in the constellation of Orion.
Iota Horologii b, often catalogued HR 810 b, is an extrasolar planet approximately 56.5 light-years away in the constellation of Horologium. Iota Horologii b has a minimum mass 2.26 times that of Jupiter; astrometric measurements from Gaia suggest it has a true mass of 6.2 MJ.
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.
14 Herculis b or 14 Her b is an exoplanet approximately 58.4 light-years away in the constellation of Hercules. The planet was found orbiting the star 14 Herculis, with a mass that would make the planet a Jovian planet roughly the same size as Jupiter but much more massive. It was discovered in July 1998 by the Geneva Extrasolar Planet Search team. The discovery was formally published in 2003. At the time of discovery it was the extrasolar planet with the longest orbital period, though longer-period planets have subsequently been discovered.
Pi Mensae, also known as HD 39091, is a yellow dwarf star in the constellation of Mensa. This star has a high proper motion. The apparent magnitude is 5.67, which can be visible to the naked eye in exceptionally dark, clear skies. It is nearly 60 light-years away. The star is slightly larger than the Sun in terms of mass, size, luminosity, temperature and metallicity, and is about 730 million years younger. It hosts three known planets.
Epsilon Eridani b, also known as AEgir [sic], is an exoplanet approximately 10.5 light-years away orbiting the star Epsilon Eridani, in the constellation of Eridanus. The planet was discovered in 2000, and as of 2023 remains the only confirmed planet in its planetary system. It orbits at around 3.5 AU with a period of around 7.6 years, and has a mass around 0.6 times that of Jupiter. As of 2023, both the Extrasolar Planets Encyclopaedia and the NASA Exoplanet Archive list the planet as 'confirmed'.
Gliese 86 is a K-type main-sequence star approximately 35 light-years away in the constellation of Eridanus. It has been confirmed that a white dwarf orbits the primary star. In 1998 the European Southern Observatory announced that an extrasolar planet was orbiting the star.
Gliese 86 b, sometimes referred to as Gliese 86 A b and/or shortened to Gl 86 b, is an extrasolar planet approximately 35 light-years away in the constellation of Eridanus. The planet was discovered orbiting a K-type main-sequence star by French scientists in November 1998. The planet orbits very close to the star, completing an orbit in 15.78 days.
HR 8799 is a roughly 30 million-year-old main-sequence star located 133.3 light-years away from Earth in the constellation of Pegasus. It has roughly 1.5 times the Sun's mass and 4.9 times its luminosity. It is part of a system that also contains a debris disk and at least four massive planets. Those planets, along with Fomalhaut b, were the first exoplanets whose orbital motion was confirmed by direct imaging. The star is a Gamma Doradus variable: its luminosity changes because of non-radial pulsations of its surface. The star is also classified as a Lambda Boötis star, which means its surface layers are depleted in iron peak elements. It is the only known star which is simultaneously a Gamma Doradus variable, a Lambda Boötis type, and a Vega-like star.
HR 8799 b is an extrasolar planet located approximately 129 light-years away in the constellation of Pegasus, orbiting the 6th magnitude Lambda Boötis star HR 8799. It has a mass between 4 and 7 Jupiter masses and a radius from 10 to 30% larger than Jupiter's. It orbits at 68 AU from HR 8799 with an unknown eccentricity and a period of 460 years, and is the outermost known planet in the HR 8799 system. Along with two other planets orbiting HR 8799, the planet was discovered on November 13, 2008 by Marois et al., using the Keck and Gemini observatories in Hawaii. These planets were discovered using the direct imaging technique.
HR 8799 c is an extrasolar planet located approximately 129 light-years away in the constellation of Pegasus, orbiting the 6th magnitude Lambda Boötis star HR 8799. This planet has a mass between 5 and 10 Jupiter masses and a radius from 20 to 30% larger than Jupiter's. It orbits at 38 AU from HR 8799 with an unknown eccentricity and a period of 190 years; it is the 2nd planet discovered in the HR 8799 system. Along with two other planets orbiting HR 8799, this planet was discovered on November 13, 2008, by Marois et al., using the Keck and the Gemini observatories in Hawaii. These planets were discovered using the direct imaging technique. In January 2010, HR 8799 c became the 3rd exoplanet to have a portion of its spectrum directly observed, confirming the feasibility of direct spectrographic studies of exoplanets.
HR 8799 e is a large exoplanet, orbiting the star HR 8799, which lies 129 light-years from Earth. This gas giant is between 5 and 10 times the mass of Jupiter. Due to their young age and high temperature all four discovered planets in the HR 8799 system are large, compared to all gas giants in the Solar System.
Strategic Explorations of Exoplanets and Disks with Subaru (SEEDS) is a multi-year survey that used the Subaru Telescope on Mauna Kea, Hawaii in an effort to directly image extrasolar planets and protoplanetary/debris disks around hundreds of nearby stars. SEEDS is a Japanese-led international project. It consists of some 120 researchers from a number of institutions in Japan, the U.S. and the EU. The survey's headquarters is at the National Astronomical Observatory of Japan (NAOJ) and led by Principal Investigator Motohide Tamura. The goals of the survey are to address the following key issues in the study of extrasolar planets and disks: the detection and census of exoplanets in the regions around solar-mass and massive stars; the evolution of protoplanetary disks and debris disks; and the link between exoplanets and circumstellar disks.
HD 27631 is a star with an orbiting exoplanet in the southern constellation of Horologium. It is too faint to be visible to the naked eye, having an apparent visual magnitude of 8.24. The distance to this system is 164 light years based on parallax measurements. It is drifting further away with a radial velocity of 21 km/s.
51 Eridani b is a "Jupiter-like" planet that orbits the young F0 V star 51 Eridani, in the constellation Eridanus. It is 96 light years away from the solar system, and it is approximately 20 million years old.
2M0437 b, or 2MASS J04372171+2651014 b, is an extrasolar planet that orbits the red dwarf of the pre-main sequence 2MASS J04372171+2651014, 418 light-years away in the constellation of Taurus. It is a gas giant, with a mass 4 times that of Jupiter. It is one of the few exoplanets directly imaged. The planet is of importance to astronomers as it challenges models of planet formation by nucleus accretion and disk instability.
