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Contact Binaries
In astronomy, a contact binary is a binary star system whose component stars are so close that they touch each other or have merged to share their gaseous envelopes. A binary system whose stars share an envelope may also be called an overcontact binary. The term "contact binary" was introduced by astronomer Gerard Kuiper in 1941. Almost all known contact binary systems are eclipsing binaries; eclipsing contact binaries are known as W Ursae Majoris variables, after their archetype star, W Ursae Majoris. In a contact binary, both stars have filled their Roche lobes, allowing the more massive primary component to transfer both mass and luminosity to the secondary member. As a result, the components in a contact binary often have similar effective temperatures and luminosities, regardless of their respective masses. The rate of energy transfer between the components is dependent on their mass ratio and luminosity ratio. In cases where the stars are in geometric contact but the the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
HR 5171
HR 5171, also known as V766 Centauri, is a yellow hypergiant in the constellation Centaurus. It is said to be either an extreme red supergiant (RSG) or recent post-red supergiant (Post-RSG) yellow hypergiant (YHG), both of which suggest it is one of the largest known stars. The star's diameter is uncertain but likely to be between 1,100 and 1,600 times that of the Sun. It is 3.6 kpc (11,700 light years) from Earth. It is a variable star, and when it is near its maximum brightness, magnitude 6.1, it is faintly visible to the naked eye under excellent observing conditions. A 2014 publication hypothesized the star to be a contact binary, sharing a common envelope of material with a smaller yellow supergiant and secondary star, the two orbiting each other every . A recent publication (2019) rules out this hypothesis, and the distance of HR 5171 has been revised to and its radius to 3-5 AU (i.e. 650 to 1080 times that of the Sun). An optical companion, HR 5171B ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
VFTS 352
VFTS 352 is a contact binary star system away in the Tarantula Nebula, which is part of the Large Magellanic Cloud. It is the most massive and earliest spectral type overcontact system known. The discovery of this O-type binary star system made use of the European Southern Observatory's Very Large Telescope, and the description was published on 13 October 2015. VFTS 352 is composed of two very hot (40,000 °C), bright and massive stars of equal size that orbit each other in little more than a day. The stars are so close that their atmospheres overlap. Both stars are rotating at a rate equal to their orbital period; that is, they are tidally locked. Extreme stars like the two components of VFTS 352 are thought to be the main producers of elements such as oxygen. The future of VFTS 352 is uncertain, and there are two possible scenarios. If the two stars merge, a very rapidly rotating star will be produced. If it keeps spinning rapidly it might end its life in a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thorne–Żytkow Object
A Thorne–Żytkow object (TŻO or TZO), a type of hybrid star, is a conjectured type of star wherein a red giant or Red supergiant star, red supergiant contains a neutron star at its core, formed from the Stellar collision, collision of the giant with the neutron star. Such objects were hypothesized by Kip Thorne and Anna Żytkow in 1977. In 2014, it was discovered that the star HV 2112, located in the Small Magellanic Cloud (SMC), was a strong candidate, though this view has since been refuted. Another possible candidate is the star HV 11417, also located in the SMC. Formation A Thorne–Żytkow object would be formed when a neutron star collides with another star, often a red giant or supergiant. The colliding objects can simply be wandering stars, though this is only likely to occur in extremely crowded globular clusters. Alternatively, the neutron star could form in a binary star, binary system when one of the two stars goes supernova. Because Supernova#Asymmetry, no super ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
MY Camelopardalis
MY Camelopardalis (MY Cam) is a binary star system located in the Alicante 1 open cluster, some away in the constellation Camelopardalis (constellation), Camelopardalis. It is one of the most massive known binary star systems and a leading candidate for a massive star merger. MY Cam is the brightest star in Alicante 1. The system consists of two hot blue O-type stars with one component having a mass of 32 solar masses and the other 38 solar masses. In 1998, the star was included in a list of suspected variable stars. John Greaves and Patrick Wils proved that it is variable, in 2004. It was given its variable star designation, MY Camelopardalis, in 2008. MY Cam is a contact binary and eclipsing binary, with an orbital period of 1.2 days, and an orbital velocity of . Both stars share a common envelope. References {{DEFAULTSORT:MY Camelopardalis Camelopardalis Common envelope binary stars Eclipsing binaries O-type main-sequence stars ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
V1309 Scorpii
V1309 Scorpii (also known as V1309 Sco) is a contact binary that merged into a single star in 2008 in a process known as a luminous red nova. It was the first star to provide conclusive evidence that contact binary systems end their evolution in a stellar merger. Its similarities to V838 Monocerotis and V4332 Sagittarii allowed scientists to identify these stars as merged contact binaries as well. Discovery V1309 Scorpii was discovered independently on 2 September 2008 by three groups: Koichi Nishiyama and Fujio Kabashima, Yukio Sakurai, and Guoyou Sun and Xing Gao. It was originally identified as a transient object located near the galactic bulge at right ascension ± 0s.01 and declination ± 0.1. The astronomers who found it noted that it had been invisible to their 12 mag limit telescope just a few days prior to its discovery, indicating that it had recently undergone an outburst. Before its eruption, its faintness and close proximity to USNO-B1.0 star 0592-0608962 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Luminous Red Nova
A luminous red nova (abbr. ''LRN'', pl. ''luminous red novae'', pl.abbr. ''LRNe'') is a stellar explosion thought to be caused by the merging of two stars. They are characterised by a distinct red colour, and a light curve that fades slowly with resurgent brightness in the infrared. Luminous red novae are not related to standard novae, which are explosions that occur on the surface of white dwarf stars. Discovery A small number of objects exhibiting the characteristics of luminous red novae have been observed over the last 30 years or so. The red star M31 RV in the Andromeda Galaxy flared brightly during 1988 and may have been a luminous red nova. In 1994, V4332 Sagittarii, a star in the Milky Way galaxy, flared similarly, and in 2002, V838 Monocerotis followed suit and was studied quite closely. The first confirmed luminous red nova was the object M85 OT2006-1, in the galaxy Messier 85. It was first observed during the Lick Observatory Supernova Search, and subsequently i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
KIC 9832227
KIC 9832227 is a contact binary star system in the constellation Cygnus (constellation), Cygnus, located about 2,060 light-years away. It is also identified as an eclipsing binary with an orbital period of almost 11 hours. Incorrect 2022 merger prediction In 2017, the system was predicted to result in a stellar collision, merger in 2022.2 (± 0.6 years), producing a luminous red nova (LRN) reaching an apparent magnitude of 2, or about the brightness of Polaris, the North Star. The LRN would remain visible to the naked eye for roughly a month. The merger of the two stellar cores was predicted to give birth to a new, hotter, more massive Main sequence, main-sequence star. However, a reanalysis of the data in September 2018 revealed that the prediction had been based on a wrongly timed observation, negating the predicted merger. The period of the variations in KIC 9832227 has been observed to be growing shorter since 2013, leading to the prediction of the merger in or arou ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Interacting Binary Star
An Interacting binary star is a type of binary star in which one or both of the component stars has filled or exceeded its Roche lobe, also known as a semidetached binary. When this happens, material from one star (the donor star) will flow towards the other star (the accretor). If the accretor is a compact star, an accretion disk may form. The physical conditions in such a system can be complex and highly variable, and they are common sources of cataclysmic outbursts. A common type of interacting binary star is one in which one of the components is a compact object which is well within its Roche lobe, while the other is an evolved giant star. If the compact object is a white dwarf, then accretion of material from the evolved star onto the white dwarf's surface may result in its mass increasing to beyond the Chandrasekhar limit. This can lead to runaway thermonuclear reactions and the massive explosion of the star in a Type I supernova. An example of such a binary star is R ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hypergiant
A hypergiant ( luminosity class 0 or Ia+) is a very rare type of star that has an extremely high luminosity, mass, size and mass loss because of its extreme stellar winds. The term ''hypergiant'' is defined as luminosity class 0 (zero) in the MKK system. However, this is rarely seen in literature or in published spectral classifications, except for specific well-defined groups such as the yellow hypergiants, RSG ( red supergiants), or blue B(e) supergiants with emission spectra. More commonly, hypergiants are classed as Ia-0 or Ia+, but red supergiants are rarely assigned these spectral classifications. Astronomers are interested in these stars because they relate to understanding stellar evolution, especially star formation, stability, and their expected demise as supernovae. Notable examples of hypergiants include the Pistol Star, a blue hypergiant located close to the Galactic Center and one of the most luminous stars known; Rho Cassiopeiae, a yellow hypergiant that is one ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Contact Binary (small Solar System Body)
A contact binary is a small Solar System body, such as a minor planet or comet, that is composed of two bodies that have gravitated toward each other until they touch, resulting in a bilobated, peanut-like overall shape. Contact binaries are distinct from true binary systems such as binary asteroids where both components are separated. The term is also used for stellar contact binaries. An example of a contact binary is the Kuiper belt object 486958 Arrokoth, which was imaged by the ''New Horizons'' spacecraft during its flyby in January 2019. History The existence of contact binary asteroids was first speculated by planetary scientist Allan F. Cook in 1971, who sought for potential explanations for the extremely elongated shape of the Jupiter trojan asteroid 624 Hektor, whose longest axis measures roughly across and is twice as long as its shorter axes according to light curve measurements. Astronomers William K. Hartmann and Dale P. Cruikshank performed further invest ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Astronomy
Astronomy is a natural science that studies celestial objects and the phenomena that occur in the cosmos. It uses mathematics, physics, and chemistry in order to explain their origin and their overall evolution. Objects of interest include planets, natural satellite, moons, stars, nebulae, galaxy, galaxies, meteoroids, asteroids, and comets. Relevant phenomena include supernova explosions, gamma ray bursts, quasars, blazars, pulsars, and cosmic microwave background radiation. More generally, astronomy studies everything that originates beyond atmosphere of Earth, Earth's atmosphere. Cosmology is a branch of astronomy that studies the universe as a whole. Astronomy is one of the oldest natural sciences. The early civilizations in recorded history made methodical observations of the night sky. These include the Egyptian astronomy, Egyptians, Babylonian astronomy, Babylonians, Greek astronomy, Greeks, Indian astronomy, Indians, Chinese astronomy, Chinese, Maya civilization, M ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
