η canis majoris
Trotz senger Distanz vun 3.200 Liichtjoer ass hie mat 2,45 m um Nuetshimmel opfaalend hell. Its great infrared (IR) excess makes it one of the brightest objects in the local part of the galaxy at wavelengths of 5 to 20 microns (µm) and indicates a dust shell or heated disk. The bolometric luminosity (Lbol) of VY CMa can be calculated from Spectral energy distribution (SED) or bolometric flux, which can be determined from photometry in several visible and infrared bands. The similarity has led at least two professional articles to propose a model that the star might evolve blueward on the Hertzsprung–Russell diagram (HR diagram) to become a yellow hypergiant, then a Luminous blue variable (LBV), and finally a Wolf–Rayet star (WR star). A very large and luminous star, VY CMa is among the most extreme stars in the Milky Way and has an effective temperature below 4,000 K (3,730 °C; 6,740 °F). With an apparent magnitude of 2.451, it is the fifth brightest star in the constellation, after Sirius, Adhara, Wezen, and Mirzam. Thanks to its high brightness, Aludra is clearly visible when observed from locations with dark skyes, and should be also quite easily visible from light polluted areas. [33] The inner shell figures as 0.12 ″ across corresponding to 140 AU (0.0022 ly) for a star 1200 parsecs away, whereas that of the outer one is at 10″, corresponding to 12,000 AU (0.19 ly). Adhil, (ε) Andromedæ, "the train of a garment," The size of the star was published at its Rosseland Radius, outside of which optical depth falls below 2⁄3,[57] given the mean of two most modern, similar but distinct distances. From this star CO emission is coincident with the bright KI shell in its asymmetric nebula. In Chinese, å¼§ç¢ (Hú ShÇ), meaning Bow and Arrow,[14] refers to an asterism consisting of Eta Canis Majoris, Delta Canis Majoris, HD 63032, HD 65456, Omicron Puppis, k Puppis, Epsilon Canis Majoris, Kappa Canis Majoris and Pi Puppis. Adopting the latter classes with the temperature scale proposed by Emily Levesque gives a range of between 3,450 and 3,535 K.[51]. There is thus a near-certain physical association of the star with Sh2-310 and with NGC 2362 in all standard models. [53][54], Early direct measurements of the radius at infrared (K-band = 2.2 µm) wavelength gave an angular diameter of 18.7±0.5 mas, corresponding to radii above 3,000 R☉ (2.1×109 km; 14 au; 1.3×109 mi) at a still very plausible distance of 1.5 kiloparsecs; a radius dwarving other known red hypergiants. )[15], Aludra shines brightly in the skies in spite of a large distance from Earth due to being intrinsically many times brighter than the Sun. VY CMa is also a pulsating star; its size changes with time. [7] It has only been around a fraction of the time the Sun has, yet is already in the last stages of its life. The traditional name Aludra originates from the Arabic: اÙعذراء al-adhraa 'the virgin'. [3][40][48], Most of the output of VY CMa is emitted as infrared radiation, with a maximum emission at 5–10 μm, which is in part caused by reprocessing of the radiation by the circumstellar nebula. Desde 1943, o espectro desta estrela tem servido como referência para a classificação de outras estrelas. Taking this mid-point estimate as correct, a quantum of light travelling at the speed of light would take 6 hours to go around its surface, compared to 14.5 seconds for the Sun. Canis Major (pronounced ˈkeɪnɪs ˈmeɪdʒər) is the Latin name of a constellation situated close to the celestial equator.As such, it is at least partly visible from both hemispheres in certain times of the year. With an apparent… Read More » Aludra. A constelação Canis Major e a estrela Aludra (η) Aludra ou é a denomiação tradicional para a estrela Eta (η) Canis Majoris da constelação Canis Major. Most of the properties of the star depend directly on its distance. [24][25][26] Molecules, such as HCN, NaCl, PN, CH, CO, CH3OH, TiO, and TiO2 have been detected. Aludra, also designated as η Canis Majoris (eta Canis Majoris), is a double supergiant star in the constellation of Canis Major . This uses the later well-reviewed effective temperature 3450–3535 Kelvin, and a luminosity of 430,000 L☉ based on SED integration and a distance of 1.5 kpc. [40] In 2012, observations of SiO masers using Very-long-baseline interferometry (VLBI) from Very Long Baseline Array (VLBA) independently derived a parallax of 0.83±0.08 mas, corresponding to a distance of 1.20+0.13−0.10 kpc (about 3,910+423−326 ly). [60], Coordinates: 07h 22m 58.33s, −25° 46′ 03.17″, Red hypergiant in the constellation Canis Major, Alcolea et al 2013 refer to VY CMa as having the highest radius "among well-characterised stars in our galaxy", referring to the Wittkowski et al. [16] Hohle and colleagues, using the parallax, extinction and analysis of spectrum, came up with a mass 19.19 times that and luminosity 105,442 times that of the Sun. Some signature changes in its spectrum correspond to temperature variations. 27 Canis Majoris là một sao đôi nằm trong chòm sao Canis Major ở khu vực phía bắc, nằm ở khoảng cách 1.700năm ánh sáng từ mặt trời. [4][55] They assert that earlier very high luminosities of 500,000 L☉ and very large radii of 2,800–3,230 R☉[17][56] (or even 4,000 R☉[23]) were based on effective temperatures below 3,000 K that were unreasonably low. One study though, gives a luminosity class of Ia+ which means a hypergiant or extremely luminous supergiant.[45]. It is located about 4 degrees directly south of Sirius. This reconstruction showed that the star's mass loss is much more complex than expected for any red supergiant or hypergiant. [31] It was given the variable star designation VY Canis Majoris in 1939, the 43rd variable star of the constellation Canis Major. Furthermore, all the vectors of velocity of Sh2-310 are very close to those of the star. It has an average mass loss rate of 6×10−4 M☉ per year, among the highest known and unusually high even for a red supergiant, as evidenced by its extensive envelope. [42][33] It is thus an exponent for the understanding of high-mass loss episodes near the end of massive star evolution. [40] Despite being one of the most luminous stars in the Milky Way, much of the visible light of VY CMa is absorbed by the circumstellar envelope, so the star needs a telescope to be observed. Ο Σείριος (α CMa / α Μεγάλου Κυνός / α Canis Majoris) είναι ο λαμπρότερος αστέρας στον νυκτερινό ουρανό με Φαινόμενο Μέγεθος −1,46. It produces strong molecular maser emission and was one of the first radio masers discovered. Sirius is the 7th closest star to Earth at 8.66 light years. From Latin canis maior (“ (the) greater dog ”). [32], VY Canis Majoris is surrounded by an extensive and dense asymmetric red reflection nebula with a total ejected mass of 0.2-0.4 M☉ and a temperature of 800 Kelvin based on a DUSTY model atmosphere that has been formed by material expelled from its central star. ε Canis Majoris , estrela dobre cunhas compoñentes que están separadas 7 segundos de arco. [23] It has been extensively studied with the aid of the Hubble Space Telescope (HST), showing that the nebula has a complex structure that includes filaments and arcs, which were caused by past eruptions; the structure is akin to that around post-red supergiant (Post-RSG) or yellow hypergiant (YHG) IRC +10420. Comparison of the effective temperature and bolometric luminosity compared to evolutionary tracks for massive stars suggest its initial mass was 25±10 M☉ for a rotating star but current mass 15 M☉ – or 32 M☉ at first if non-rotating falling to present-day 19 M☉,[3] and an age of 8.2 million years (Myr). [46][47] In 2006, its temperature was calculated to be as high as 3,650±25 K, corresponding to a spectral class of M2.5,[4] yet this star is usually considered as an M4 to M5 star. [2][9] In the General Catalogue of Variable Stars (GCVS) it is classed a semiregular variable of sub-type SRc, indicating a cool supergiant,[2] although it is classed as a type LC slow irregular variable star in the American Association of Variable Star Observers (AAVSO) Variable Star Index. Aludra – η Canis Majoris (Eta Canis Majoris) Aludra is an Alpha Cygni type variable star, with luminosity varying between magnitude 2.38 and 2.48. [38], Distances can be calculated by measuring the change in position against very distant background objects as the telescope orbits the Sun. 25 times more luminous than the Sun its surface would, per approximation... Of its life 1847, VY Canis Majoris is the star at speeds! Served as one of the star will certainly explode as a supernova within the next million... Below 3,000 K based on the Wittkowski radius and the Monnier radius put mean size at R☉... Resemble a Dog following the hunter Orion star yet less than 10 million years ] [ 18 ] is. 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