Artist's conception of planet orbiting Psi1 Aquarii | |
Discovery | |
---|---|
Discovered by | Mitchell et al. |
Discovery site | United States |
Discovery date | 16 November 2013 |
Radial velocity | |
Orbital characteristics | |
0.7 AU (100,000,000 km) | |
Eccentricity | 0.027 ± 0.026 |
181.4 ± 0.1 d | |
April 11, 2005 2453472.1 ± 24 | |
177.3 ± 0.8 | |
Semi-amplitude | 91.0 ± 2.3 |
91 Aquarii b, also known as HD 219449 b, is an extrasolar planet orbiting in the 91 Aquarii system approximately 148 light-years away in the constellation of Aquarius. It orbits at the average distance of 105 Gm from its star, which is slightly closer than Venus is to the sun (108 Gm). The planet takes half an Earth year to orbit around the star in a very circular orbit with eccentricity less than 0.053.
Aquarius is a constellation of the zodiac, between Capricornus and Pisces. Its name is Latin for "water-carrier" or "cup-carrier", and its symbol is , a representation of water. Aquarius is one of the oldest of the recognized constellations along the zodiac. It was one of the 48 constellations listed by the 2nd century astronomer Ptolemy, and it remains one of the 88 modern constellations. It is found in a region often called the Sea due to its profusion of constellations with watery associations such as Cetus the whale, Pisces the fish, and Eridanus the river.
HD 209458 b, also given the nickname Osiris, is an exoplanet that orbits the solar analog HD 209458 in the constellation Pegasus, some 159 light-years from the Solar System. The radius of the planet's orbit is 7 million kilometres, about 0.047 astronomical units, or one eighth the radius of Mercury's orbit. This small radius results in a year that is 3.5 Earth days long and an estimated surface temperature of about 1,000 °C. Its mass is 220 times that of Earth and its volume is some 2.5 times greater than that of Jupiter. The high mass and volume of HD 209458 b indicate that it is a gas giant.
HD 37124 is a star in the equatorial constellation of Taurus, positioned about a half degree to the SSW of the bright star Zeta Tauri. The apparent visual magnitude of this star is 7.68, which is too dim to be visible to the naked eye. It is located at a distance of 103 light years from the Sun based on parallax, but is drifting closer with a radial velocity of −23 km/s. Three extrasolar planets have been found to orbit the star.
EZ Aquarii is a triple star system approximately 11.3 ly (3.5 pc) from the Sun in the constellation Aquarius. It is also known as Luyten 789-6 and Gliese 866 and all three components are M-type red dwarfs. The pair EZ Aquarii AC form a spectroscopic binary with a 3.8-day orbit and a 0.03 AU separation. This pair share an orbit with EZ Aquarii B that has an 823-day period. The A and B components of Luyten 789-6 together emit X-rays.
Xi Aquarii is a binary star system in the equatorial constellation of Aquarius. It is visible to the naked eye with an apparent visual magnitude of 4.7. Based upon parallax measurements made during the Hipparcos mission, this system lies at a distance of around 179 light-years from the Sun.
Sudarsky's classification of gas giants for the purpose of predicting their appearance based on their temperature was outlined by David Sudarsky and colleagues in the paper Albedo and Reflection Spectra of Extrasolar Giant Planets and expanded on in Theoretical Spectra and Atmospheres of Extrasolar Giant Planets, published before any successful direct or indirect observation of an extrasolar planet atmosphere was made. It is a broad classification system with the goal of bringing some order to the likely rich variety of extrasolar gas-giant atmospheres.
91 Aquarii is the Flamsteed designation for a triple star system in the equatorial constellation of Aquarius. It also bears the Bayer designation Psi1 Aquarii. It is visible to the naked eye with an apparent visual magnitude of +4.248. Parallax measurements yield an estimated distance of around 150 light-years from Earth. An extrasolar planet is known to orbit the main star.
Doppler spectroscopy is an indirect method for finding extrasolar planets and brown dwarfs from radial-velocity measurements via observation of Doppler shifts in the spectrum of the planet's parent star.
HD 10647 b, also catalogued as q1 Eridani b, is an extrasolar planet approximately 57 light-years away in the constellation of Eridanus. The planet is a mid-Jovian that orbits 103% farther from the star than Earth to the Sun. It takes about 33 months to orbit with semi-amplitude of 17.9 m/s.
HD 117618 b, named Noifasui by the IAU, is an exoplanet discovered orbiting the star HD 117618 in September 2004. The planet is a small gas giant less than a fifth the mass of Jupiter. It orbits close to its star in a very eccentric orbit.
HD 59686 b is an extrasolar planet that orbits at 91.1% of distance between Earth and the Sun or 0.911 AU in a very circular orbit of the giant star HD 59686.
HD 40307 b is an extrasolar planet orbiting the star HD 40307, located 42 light-years away in the direction of the southern constellation Pictor. The planet was discovered by the radial velocity method, using the European Southern Observatory's HARPS apparatus, in June 2008. It is the second smallest of the planets orbiting the star, after HD 40307 e. The planet is of interest as this star has relatively low metallicity, supporting a hypothesis that different metallicities in protostars determine what kind of planets they will form.
HD 154672 b is an extrasolar planet located approximately 210 light-years away in the constellation of Ara, orbiting the metal-rich and aged star HD 154672. This planet has a minimum mass five times that of Jupiter and orbits at about 60% the distance between the Earth to the Sun. Its orbit is very elliptical, which causes temperatures on the planet to vary significantly as it proceeds along its orbit. This planet was discovered in Las Campanas Observatory on September 5, 2008 using the radial velocity method. Along with HD 205739 b, the planets were the first to be discovered by the N2K Consortium using the Magellan Telescopes.
A circumbinary planet is a planet that orbits two stars instead of one. Planets in stable orbits around one of the two stars in a binary are known. New studies showed that there is a strong hint that the planet and stars originate from a single disk.
HD 28254 is an 8th magnitude G-type main sequence star located approximately 178 light years away in the constellation Dorado. This star is larger, cooler, brighter, and more massive than our Sun. Also its metal content is 2.3 times as much as the Sun. In 2009, a gas giant planet was found in orbit around the star.
HD 13931 is a Sun-like star in the northern constellation of Andromeda. It can be viewed with binoculars or a small telescope but is too faint to be seen with the naked eye, having an apparent visual magnitude of 7.60. This object is located at a distance of 155 light years from the Sun, as determined from its parallax, and is drifting further away with a radial velocity of +30 km/s.
Gliese 179 b is an extrasolar planet which orbits the M-type main sequence star Gliese 179, located approximately 40 light years away in the constellation Orion. This planet has a minimum mass a little bit less than Jupiter and it orbits at 2.41 AU or 361 Gm from the star with an eccentricity slightly less than Pluto. The planetary distance ranges from 1.90 to 2.92 AU. This planet was discovered by using radial velocity method from spectrograph taken at Keck Observatory on November 13, 2009.
An exoplanet is a planet located outside the Solar System. The first evidence of an exoplanet was noted as early as 1917, but was not recognized as such until 2016. No planet discovery has yet come from that evidence. However, the first scientific detection of an exoplanet began in 1988. Afterwards, the first confirmed detection came in 1992, with the discovery of several terrestrial-mass planets orbiting the pulsar PSR B1257+12. The first confirmation of an exoplanet orbiting a main-sequence star was made in 1995, when a giant planet was found in a four-day orbit around the nearby star 51 Pegasi. Some exoplanets have been imaged directly by telescopes, but the vast majority have been detected through indirect methods, such as the transit method and the radial-velocity method. As of 1 March 2021, there are 4,687 confirmed exoplanets in 3,463 systems, with 770 systems having more than one planet. This is a list of the most notable discoveries.
HD 200964 is a 7th magnitude star located approximately 237 light-years away in the constellation of Equuleus. It is a K-type subgiant with 44% more mass than the Sun, but cooler. At the age of 3 billion years, it indicates that it is an evolved A-type star. At a magnitude of 6.64, this star is too faint to be seen with the naked eye for most people, but binoculars would make it easy to see this star. Only people with a very clear eyesight and very dark sky can barely see this star.
HD 219134 c, also known as HR 8832 c, is a hot, dense, rocky exoplanet orbiting around the K-type star HD 219134 in the constellation of Cassiopeia. Originally thought to be a little less than three times the mass of Earth, it is now known to be over 4 times the mass and 51% larger in radius, suggesting a rocky composition with a higher quantity of iron than Earth. The exoplanet was initially detected by the instrument HARPS-N of the Italian Telescopio Nazionale Galileo via the radial velocity method. Transits of the planet were observed by the Spitzer Space Telescope in 2017. Later that year, it was predicted that HD 219134 c has an atmosphere.
Coordinates: 23h 15m 53.5s, −09° 05′ 16″