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HD 47186
HD 47186 is a star with a pair of orbiting exoplanets in the southern constellation of Canis Major. The system is located at a distance of 122 light years from the Sun based on parallax measurements, and is drifting further away with a radial velocity of 4.2 km/s. Although it has an absolute magnitude of 4.64, at the distance of this system the apparent visual magnitude is 7.63; too faint to be seen with the naked eye. It has a high proper motion, traversing the celestial sphere at an angular rate of ·yr−1. The spectrum of HD 47186 matches a G-type main-sequence star with a stellar classification of G6V. It is an estimated 5.5 billion years old and is spinning with a projected rotational velocity of 2 km/s. The star has 5% greater mass and a 12% larger girth compared to the Sun. The abundance of iron, a measure of the star's metallicity, is 1.7 times more than the Sun, making it metal-rich. HD 47186 is radiating 1.2 times the luminosity of the Sun ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Canis Major
Canis Major is a constellation in the southern celestial hemisphere. In the second century, it was included in Ptolemy's 48 constellations, and is counted among the 88 modern constellations. Its name is Latin for "greater dog" in contrast to Canis Minor, the "lesser dog"; both figures are commonly represented as following the constellation of Orion (constellation), Orion the hunter through the sky. The Milky Way passes through Canis Major and several open clusters lie within its borders, most notably Messier 41, M41. Canis Major contains Sirius, the brightest star in the night sky, known as the "dog star". It is bright because of its proximity to the Solar System and its intrinsic brightness. In contrast, the other bright stars of the constellation are stars of great distance and high luminosity. At magnitude 1.5, Epsilon Canis Majoris (Adhara) is the second-brightest star of the constellation and the brightest source of extreme ultraviolet radiation in the night sky. Next in b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Photosphere
The photosphere is a star's outer shell from which light is radiated. It extends into a star's surface until the plasma becomes opaque, equivalent to an optical depth of approximately , or equivalently, a depth from which 50% of light will escape without being scattered. A photosphere is the region of a luminous object, usually a star, that is transparent to photons of certain wavelengths. Stars, except neutron stars, have no solid or liquid surface. Therefore, the photosphere is typically used to describe the Sun's or another star's visual surface. Etymology The term ''photosphere'' is derived from Ancient Greek roots, φῶς, φωτός/''phos'', ''photos'' meaning "light" and σφαῖρα/''sphaira'' meaning "sphere", in reference to it being a spherical surface that is perceived to emit light. Temperature The surface of a star is defined to have a temperature given by the effective temperature in the Stefan–Boltzmann law. Various stars have photospheres of vari ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
The Astronomical Journal
''The Astronomical Journal'' (often abbreviated ''AJ'' in scientific papers and references) is a peer-reviewed monthly scientific journal owned by the American Astronomical Society (AAS) and currently published by IOP Publishing. It is one of the premier journals for astronomy in the world. Until 2008, the journal was published by the University of Chicago Press on behalf of the AAS. The reasons for the change to the IOP were given by the society as the desire of the University of Chicago Press to revise its financial arrangement and their plans to change from the particular software that had been developed in-house. The other two publications of the society, the ''Astrophysical Journal'' and its supplement series, followed in January 2009. The journal was established in 1849 by Benjamin A. Gould. It ceased publication in 1861 due to the American Civil War, but resumed in 1885. Between 1909 and 1941 the journal was edited in Albany, New York. In 1941, editor Benjamin Boss arranged ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
MOA-2007-BLG-192L
MOA-2007-BLG-192Lb, occasionally shortened to MOA-192 b, is an extrasolar planet approximately 7,000 light-years away in the constellation of Sagittarius (constellation), Sagittarius. The planet was discovered orbiting the low-mass star MOA-2007-BLG-192L. It was found when it caused a gravitational microlensing event on May 24, 2007, which was detected as part of the Microlensing Observations in Astrophysics, MOA-II microlensing survey at the Mount John University Observatory in New Zealand. The mass of the planet is not well-known. It is anything between 2.75 and 105 Earth mass, Earth masses (), although it is more likely to be between . The mass range also means that the planet's classification varies, from a Super-Earth to a Sub-Saturn. It is located at 2.02 Astronomical unit, astronomical units from its host star. Host star MOA-2007-BLG-192L is a red dwarf star, one of the smallest and least massive type of stars, as well as one of the most numerous in the Milky Way. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
HD 40307
HD 40307 is an orange ( K-type) main-sequence star located approximately 42 light-years away in the constellation of Pictor (the Easel), taking its primary name from its Henry Draper Catalogue designation. It is calculated to be slightly less massive than the Sun. The star has six known planets, three discovered in 2008 and three more in 2012. One of them, HD 40307 g, is a potential super-Earth in the habitable zone, with an orbital period of about 200 days. This object might be capable of supporting liquid water on its surface, although much more information must be acquired before its habitability can be assessed. No stellar companions to HD 40307 were detected as of 2018. History and nomenclature HD 40307 was observed during or before 1900 as part of the Cape Photographic Durchmusterung. The designation ''HD 40307'' is from the Henry Draper Catalogue, which is based on spectral classifications made between 1911 and 1915 by Annie Jump Cannon and her co-workers, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
HD 181433
HD 181433 is a star with a system of orbiting exoplanets located in the southern constellation of Pavo (the Peacock). With an apparent visual magnitude of 8.40, it is too faint to be visible to the naked eye. It lies at a distance of 88 light years from the Sun based on parallax measurements, and is drifting further away with a radial velocity of +40 km/s. The system shows a high proper motion, traversing the celestial sphere at an angular rate of . This K-type star has a stellar classification of K3III-IV, which presents it as an evolved star with mixed traits of a red giant and a subgiant. G. Campanella and associates list a class of K3IV. These are inconsistent with the fact that its luminosity is only 0.34 times that of the Sun. Its entry in the Hipparcos catalogue lists a spectral type of K5V, classifying it as an ordinary K-type main-sequence star, an orange dwarf. HD 181433 is an older star with age estimates of around 7 billion years. It is smaller than ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
4 Vesta
Vesta (minor-planet designation: 4 Vesta) is one of the largest objects in the asteroid belt, with a mean diameter of . It was discovered by the German astronomer Heinrich Wilhelm Matthias Olbers on 29 March 1807 and is named after Vesta (mythology), Vesta, the virgin goddess of home and hearth from Roman mythology. Vesta is thought to be the second-largest asteroid, both by mass and by volume, after the dwarf planet Ceres (dwarf planet), Ceres. Measurements give it a nominal volume only slightly larger than that of 2 Pallas, Pallas (about 5% greater), but it is 25% to 30% more massive. It constitutes an estimated 9% of the mass of the asteroid belt. Vesta is the only known remaining rocky protoplanet of the kind that formed the terrestrial planets. Numerous fragments of Vesta were ejected by collisions one and two billion years ago that left two enormous craters occupying much of Vesta's southern hemisphere. Debris from these events has fallen to Earth as HED meteorite, howardi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Asteroid
An asteroid is a minor planet—an object larger than a meteoroid that is neither a planet nor an identified comet—that orbits within the Solar System#Inner Solar System, inner Solar System or is co-orbital with Jupiter (Trojan asteroids). Asteroids are rocky, metallic, or icy bodies with no atmosphere, and are broadly classified into C-type asteroid, C-type (carbonaceous), M-type asteroid, M-type (metallic), or S-type asteroid, S-type (silicaceous). The size and shape of asteroids vary significantly, ranging from small rubble piles under a kilometer across to Ceres (dwarf planet), Ceres, a dwarf planet almost 1000 km in diameter. A body is classified as a comet, not an asteroid, if it shows a coma (tail) when warmed by solar radiation, although recent observations suggest a continuum between these types of bodies. Of the roughly one million known asteroids, the greatest number are located between the orbits of Mars and Jupiter, approximately 2 to 4 astronomical unit, AU ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
HD 47186 C
HD 47186 c is an extrasolar planet located approximately 123 light years away in the constellation of Canis Major, orbiting the star HD 47186. This planet has a minimum mass of 0.35061 times that of Jupiter, or 1.1712 times that of Saturn. It takes 1353.6 days or 3.7059 years to revolve around the star in about the same eccentricity as the dwarf planet Pluto. This planet orbits at about the same distance from the star as the asteroid Vesta is from the Sun The Sun is the star at the centre of the Solar System. It is a massive, nearly perfect sphere of hot plasma, heated to incandescence by nuclear fusion reactions in its core, radiating the energy from its surface mainly as visible light a .... References External links * Canis Major Exoplanets discovered in 2008 Giant planets Exoplanets detected by radial velocity {{extrasolar-planet-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Outer Planet
The Solar SystemCapitalization of the name varies. The International Astronomical Union, the authoritative body regarding astronomical nomenclature, specifies capitalizing the names of all individual astronomical objects but uses mixed "Solar System" and "solar system" structures in theinaming guidelines document. The name is commonly rendered in lower case ('solar system'), as, for example, in the ''Oxford English Dictionary'' an''Merriam-Webster's 11th Collegiate Dictionary''. is the gravitationally bound Planetary system, system of the Sun and the objects that orbit it. It Formation and evolution of the Solar System, formed about 4.6 billion years ago when a dense region of a molecular cloud collapsed, forming the Sun and a protoplanetary disc. The Sun is a typical star that maintains a hydrostatic equilibrium, balanced equilibrium by the thermonuclear fusion, fusion of hydrogen into helium at its stellar core, core, releasing this energy from its outer photosphere. As ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hot Neptune
A hot Neptune is a type of giant planet with a mass similar to that of Neptune or Uranus orbiting close to its star, normally within less than 1 AU. The first hot Neptune to be discovered with certainty was Gliese 436 b (Awohali) in 2007, an exoplanet about 33 light years away. Recent observations have revealed a larger potential population of hot Neptunes in the Milky Way than was previously thought. Hot Neptunes may have formed either ''in situ'' or ''ex situ''. General characteristics Because of their close proximity to their parent stars, hot Neptunes have a much greater rate and chance of transiting their star as seen from a farther outlying point, than planets of the same mass in larger orbits. This increases the chances of discovering them by transit-based observation methods. Transiting hot Neptunes include Gliese 436 b (Awohali) and HAT-P-11b. Gliese 436 b was the first hot Neptune to be discovered with certainty in 2007. The exoplanet Mu Arae c (Dulcinea) discove ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
HD 47186 B
HD 47186 b is a “hot Neptune” extrasolar planet located approximately 123 light years away in the constellation of Canis Major, orbiting the star HD 47186. This planet has a minimum mass of 22.78 times that of Earth and orbits very close to the star at a similar distance from the star as 51 Pegasi b is from 51 Pegasi. As in consequence, it takes 4.0845 days to complete an orbit with an eccentricity Eccentricity or eccentric may refer to: * Eccentricity (behavior), odd behavior on the part of a person, as opposed to being "normal" Mathematics, science and technology Mathematics * Off-Centre (geometry), center, in geometry * Eccentricity (g ... of 0.038, which is similar to the 5.66 year-period planet HD 70642 b. References External links * Canis Major Exoplanets discovered in 2008 Giant planets Exoplanets detected by radial velocity Hot Neptunes {{extrasolar-planet-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
