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HD 4391
HD 4391 is a triple star system in the constellation Phoenix (constellation), Phoenix that is located at a distance of 48.7 light years from the Sun. The primary has a stellar classification of G3V, which is a G-type main sequence star. The physical properties of this star are similar to the Sun, making it a solar analog. However, it is believed to have 22% greater mass than the Sun and is only 1.2 billion years old. The spectrum for this star displays an abnormally low level of beryllium, which may be the result of some form of mixing process. No planet has been detected in orbit around this star, nor does it emit a statistically significant infrared excess, excess of infrared radiation that might indicate a debris disk. However, it has two companions that share a common proper motion through space with HD 4391, effectively making it a triple star system. The first, a red dwarf of type M4, lies at an angular separation of 17″ from the primary. The second is a type M5 sta ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phoenix (constellation)
Phoenix is a minor constellation in the southern sky. Named after the mythical phoenix, it was first depicted on a celestial atlas by Johann Bayer in his 1603 ''Uranometria''. The French explorer and astronomer Nicolas Louis de Lacaille charted the brighter stars and gave their Bayer designations in 1756. The constellation stretches from roughly −39° to −57° declination, and from 23.5h to 2.5h of right ascension. The constellations Phoenix, Grus, Pavo and Tucana, are known as the Southern Birds. The brightest star, Alpha Phoenicis, is named Ankaa, an Arabic word meaning 'the Phoenix'. It is an orange giant of apparent magnitude 2.4. Next is Beta Phoenicis, actually a binary system composed of two yellow giants with a combined apparent magnitude of 3.3. Nu Phoenicis has a dust disk, while the constellation has ten star systems with known planets and the recently discovered galaxy clusters El Gordo and the Phoenix Cluster—located 7.2 and 5.7 billion light years away ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Debris Disk
A debris disk (American English), or debris disc (Commonwealth English), is a circumstellar disk of dust and debris in orbit around a star. Sometimes these disks contain prominent rings, as seen in the image of Fomalhaut on the right. Debris disks are found around stars with mature planetary systems, including at least one debris disk in orbit around an evolved neutron star. Debris disks can also be produced and maintained as the remnants of collisions between planetesimals, otherwise known as asteroids and comets. By 2001, more than 900 candidate stars had been found to possess a debris disk. They are usually discovered by examining the star system in infrared light and looking for an excess of radiation beyond that emitted by the star. This excess is inferred to be radiation from the star that has been absorbed by the dust in the disk, then re-radiated away as infrared energy. Debris disks are often described as massive analogs to the debris in the Solar System. Most known de ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gliese And GJ Objects
Gliese may refer to: * Rochus Gliese (1891—1978), a German actor, director, production designer, and art director * Wilhelm Gliese (1915–1993), a German astronomer, best known for the Gliese Catalogue of Nearby Stars * Gliese Catalogue of Nearby Stars, a modern star catalog of stars located within 25 parsecs of the Earth * Gliese 163, a red dwarf located 49 light years from the Sun * Gliese 229, a binary system composed of a red dwarf and a brown dwarf about 19 light years away in the constellation Lepus. * Gliese 581, a red dwarf orbited by several extra-solar planets, at least ** Gliese 581d, a planet in the star's habitable zone * Gliese 667, a triple star system in the constellation of Scorpius containing exoplanet GJ 667 Cc in one of the stars' habitable zone * Gliese 682, a red dwarf in the constellation of Scorpius with two candidate planets, one of which is in the star's habitable zone * Gliese 710, a star projected to pass through the Oort Cloud in 1.35 million years ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hipparcos Objects
''Hipparcos'' was a scientific satellite of the European Space Agency (ESA), launched in 1989 and operated until 1993. It was the first space experiment devoted to precision astrometry, the accurate measurement of the positions of celestial objects on the sky. This permitted the first high-precision measurements of the intrinsic brightnesses (compared to the less precise apparent brightness), proper motions, and parallaxes of stars, enabling better calculations of their distance and tangential velocity. When combined with radial velocity measurements from spectroscopy, astrophysicists were able to finally measure all six quantities needed to determine the motion of stars. The resulting ''Hipparcos Catalogue'', a high-precision catalogue of more than 118,200 stars, was published in 1997. The lower-precision ''Tycho Catalogue'' of more than a million stars was published at the same time, while the enhanced Tycho-2 Catalogue of 2.5 million stars was published in 2000. ''Hipparcos'' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
