|
Van Biesbroeck's Star Catalog
In 1961 the astronomer George Van Biesbroeck published a catalog of low luminosity stars discovered using the Otto Struve Telescope, Otto Struve refractor telescope of the McDonald Observatory in Texas. Survey and catalog This survey is similar to earlier dim star surveys that were done by Max Wolf and Frank Elmore Ross but using later equipment and techniques that could detect even fainter stars. The stars in this catalog are all low luminosity stars that appear near known high proper motion stars in the telescope's field of view. The high proper motion indicates that the stars are close enough to Earth for a dim star to be seen with a large telescope. Presuming that these high proper motion stars might be binary stars with dim, previously undetected, companions, he took astrophotography, astrophotographs of the space around these stars looking for low luminosity stars that shared the high proper motions of the primary star. In general, the primary stars were too dim for a direct ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
George Van Biesbroeck
George A. Van Biesbroeck (or Georges-Achille Van Biesbroeck, , January 21, 1880 – February 23, 1974) was a Belgian–American astronomer. He worked at observatories in Belgium, Germany and the United States. He specialized in the observation of double stars, asteroids and comets. He is notable for his long career as an observational astronomer. Life He was born in Ghent, Belgium on January 21, 1880, to a family of artists. At his father's request he pursued, and in 1902, he received, the 1st degree of Civil Engineering Construction and began work as a civil engineer for the Brussels Department of Roads and Bridges. But his true vocation is not there, it was astronomy, and while performing his official duties as a civil engineer he joined volunteers at the Uccle Observatory. In 1904 he left civil engineering behind and joined the staff at the Royal Observatory of Belgium at Uccle. He then enrolled at Ghent University and obtained a degree in theoretical astronomy. He worked ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
VB 10
VB 10 or Van Biesbroeck's star is a small and dim red dwarf located in the constellation Aquila. It is part of a binary star system. VB 10 is historically notable as it was the least luminous and least massive known star from its discovery in 1944, until 1982 when LHS 2924 was shown to be less luminous. Although it is relatively close to Earth, at about 19 light years, VB 10 is a dim magnitude 17, making it difficult to image with amateur telescopes as it can get lost in the glare of the primary star. VB 10 is also the primary standard for the M8V spectral class. History VB 10 was discovered in 1944 by the astronomer George van Biesbroeck using the Otto Struve reflector telescope at the McDonald Observatory. He found it while surveying the telescopic field of view of the high- proper-motion red dwarf Gliese 752 (Wolf 1055), for companions. Wolf 1055 had been catalogued 25 years earlier by German astronomer Max Wolf using similar astrophotographic techniques. It is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
HD 219617
HD 219617 is a binary star system some 220 light-years away from the Solar System in the constellation Aquarius. It is composed of two metal-poor F-type subdwarf stars orbiting each other in a 388-year orbit. Another theory suggests that the binary star is composed of subgiant stars. Unlike many halo stars, which exhibit an excess of alpha elements relative to iron, HD 219617 is depleted in iron peak The iron peak is a local maximum in the vicinity of Iron, Fe (Chromium, Cr, Manganese, Mn, Fe, Cobalt, Co and Nickel, Ni) on the graph of the abundances of the chemical elements. For elements lighter than iron on the periodic table, nuclear fusio ... and alpha elements, although alpha elements concentrations are poorly constrained. The stellar chemical composition is peculiar, being relatively oxygen-enriched and extremely depleted in neutron capture elements. The helium fraction of the binary star at present cannot be reliably determined, and appears to be near the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gliese 752
Gliese 752 is a binary star system in the Aquila constellation. This system is relatively nearby, at a distance of . The Gliese 752 system consists of two M-type stars. The primary star is the magnitude 9 ''Gliese (GJ) 752 A''. The secondary star is the dim magnitude 17 ''Gliese (GJ) 752 B'', more commonly referred to as '' VB 10''. This stellar pair form a binary star system separated by about 74 arc seconds (~434 AU). This system is also known for its high proper motion of about 1 arc second a year. Component A has one known exoplanet. The name and number are from the '' Catalogue of Nearby Stars'', published by German astronomer Wilhelm Gliese in 1969. Gliese 752 A characteristics The primary star, also known as ''Wolf 1055'', is a type M2.5 red dwarf with about half the size and mass as the Sun and considerably cooler at . This star was first observed to be a high proper motion star by the German astronomer Max Wolf with his pioneering use of astrophotograp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
V1054 Ophiuchi
V1054 Ophiuchi, together with the star Gliese 643, is a nearby quintuple star system, located in the constellation Ophiuchus at a distance of 21.2 light-years. It consists of five stars, all of which are red dwarfs. The alternative designation of Wolf 630 forms the namesake of a moving group of stars that share a similar motion through space. Overview Hierarchy of orbits in the system V1054 Ophiuchi/Gliese 643 is the nearest quintuple star system; the next nearest star systems with at least five stars are Xi Ursae Majoris (quintuple, including a brown dwarf) at 28.5 light-years, Castor (sextuple) at 49.2 light-years, and GJ 2069 (quintuple) at 54.3 light-years. V1054 Ophiuchi and Xi Ursae Majoris are the only two quintuple star systems within 10 parsecs. The system consists of three widely separated parts: *close triple subsystem V1054 Ophiuchi A-Bab (including very close binary subsystem V1054 Ophiuchi Bab) *Gliese 643 *V1054 Ophiuchi C (vB 8) ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
HD 102365
HD 102365 (66 G. Centauri) is a binary star system that is located in the northeastern part of the Centaurus constellation, at a distance of about from the Solar System. The larger member of the system is a G-type star that is smaller than the Sun but of similar mass. It has a common proper motion companion that was discovered by W. J. Luyten in 1960. This M-type star appears to be in a wide orbit around the primary at a current separation of about 211 astronomical units (AU), (or 211 times the separation of the Earth from the Sun). By comparison, Neptune orbits at an average distance of 30 AU. Description The stellar classification for the primary star in this system is G2V; the same as the Sun. That of the red dwarf companion is M4V. The primary star has an estimated 84% the mass of the Sun, 99% of the Sun's radius, and 86% of the Sun's luminosity. It is a slow rotator, with a projected rotational velocity of 0.5 km/s. Age estimates range from 4.5 to 5.7 bil ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
HR 4458
HR 4458 (HD 100623) is a binary star system 31.18 light-years away in the equatorial constellation of Hydra. It has the Flamsteed designation 20 Crateris and the Gould designation 289 G. Hydrae; the former refers to the constellation Crater, but when the IAU formally defined constellation boundaries, it was placed in Hydra. This object is visible to the naked eye as a dim, orange-hued star with an apparent visual magnitude of 5.97. It is moving closer to the Earth with a heliocentric radial velocity of −22 km/s. The primary component is a K-type main-sequence star with a stellar classification of K0 V. It is around five billion years old with 84% of the Sun's radius. The star is radiating 37% of the Sun's luminosity from its photosphere at an effective temperature of 5,241 K. It has been examined for the presence of an infrared excess, but none was detected. There is a 15th-magnitude common proper motion companion at an angular separation of , corre ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
171 G
Year 171 ( CLXXI) was a common year starting on Monday of the Julian calendar. At the time, it was known in Rome as the Year of the Consulship of Severus and Herennianus (or, less frequently, year 924 ''Ab urbe condita''). The denomination 171 for this year has been used since the early medieval period, when the Anno Domini calendar era became the prevalent method in Europe for naming years. Events By place Roman Empire * Emperor Marcus Aurelius forms a new military command, the ''praetentura Italiae et Alpium''. Aquileia is relieved, and the Marcomanni are evicted from Roman territory. * Marcus Aurelius signs a peace treaty with the Quadi and the Sarmatian Iazyges. The Germanic tribes of the Hasdingi (Vandals) and the Lacringi become Roman allies. * Armenia and Mesopotamia become protectorates of the Roman Empire. * The Costoboci cross the Danube (Dacia) and ravage Thrace in the Balkan Peninsula. They reach Eleusis, near Athens, and destroy the temple of the Eleusini ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gamma Leporis
Gamma Leporis, Latinized from γ Leporis, is a star in the southern half of the constellation Lepus, southeast of Beta Leporis and southwest of Delta Leporis. With an apparent visual magnitude of 3.587, it is bright enough to be seen with the naked eye. Based upon an annual parallax shift of as seen from Earth, its distance can be calculated as 29.04 light-years. It has a common proper motion companion, AK Leporis (or Gamma Leporis B), which is a variable star of the BY Draconis type and has an average brightness of magnitude 6.28. The two are apart can be well seen in binoculars. Gamma Leporis is a member of the Ursa Major Moving Group. Gamma Leporis is an F-type main-sequence star with a stellar classification of F6 V. It is larger than the Sun with 1.30 times the radius of the Sun and 1.17 times the Sun's mass. The star is around 1.3 billion years old and is spinning with a rotation period of about six days. Based upon its stellar characteristics and di ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Parallax
Parallax is a displacement or difference in the apparent position of an object viewed along two different sightline, lines of sight and is measured by the angle or half-angle of inclination between those two lines. Due to perspective (graphical), foreshortening, nearby objects show a larger parallax than farther objects, so parallax can be used to determine distances. To measure large distances, such as the distance of a planet or a star from Earth, astronomers use the principle of parallax. Here, the term ''Stellar parallax, parallax'' is the semi-angle of inclination between two sight-lines to the star, as observed when Earth is on opposite sides of the Sun in its orbit. These distances form the lowest rung of what is called "the cosmic distance ladder", the first in a succession of methods by which astronomers determine the distances to celestial objects, serving as a basis for other distance measurements in astronomy forming the higher rungs of the ladder. Because parallax ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Proper Motion
Proper motion is the astrometric measure of changes in the apparent places of stars or other celestial objects as they move relative to the center of mass of the Solar System. It is measured relative to the distant stars or a stable reference such as the International Celestial Reference Frame (ICRF). Patterns in proper motion reveal larger structures like stellar streams, the general rotation of the Milky Way disk, and the random motions of stars in the Galactic halo. The components for proper motion in the equatorial coordinate system (of a given epoch, often J2000.0) are given in the direction of right ascension (''μ''α) and of declination (''μ''δ). Their combined value is computed as the ''total proper motion'' (''μ''). It has dimensions of angle per time, typically arcseconds per year or milliarcseconds per year. Knowledge of the proper motion, distance, and radial velocity allows calculations of an object's motion from the Solar System's frame of reference an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Declination
In astronomy, declination (abbreviated dec; symbol ''δ'') is one of the two angles that locate a point on the celestial sphere in the equatorial coordinate system, the other being hour angle. The declination angle is measured north (positive) or south (negative) of the celestial equator, along the hour circle passing through the point in question. The root of the word ''declination'' (Latin, ''declinatio'') means "a bending away" or "a bending down". It comes from the same root as the words ''incline'' ("bend forward") and ''recline'' ("bend backward"). In some 18th and 19th century astronomical texts, declination is given as ''North Pole Distance'' (N.P.D.), which is equivalent to 90 – (declination). For instance an object marked as declination −5 would have an N.P.D. of 95, and a declination of −90 (the south celestial pole) would have an N.P.D. of 180. Explanation Declination in astronomy is comparable to geographic latitude, projected onto the celestial sphere, and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
