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Stellar Streams
This is a list of stellar streams. A stellar stream is an association of stars orbiting a galaxy that was once a globular cluster or dwarf galaxy that has now been torn apart and stretched out along its orbit by tidal forces. An exception in the list about Milky Way streams given below is the Magellanic Stream, composed of gas (mostly hydrogen). Local Group streams Milky Way streams Andromeda Galaxy streams Streams beyond the Local Group See also * Lists of astronomical objects * List of nearby stellar associations and moving groups * Field of Streams * Stellar kinematics * Galaxy merger * Local Bubble * Satellite galaxies of the Milky Way The Milky Way has several smaller galaxies gravitationally bound to it, as part of the Milky Way subgroup, which is part of the local galaxy cluster, the Local Group. There are 59 small galaxies confirmed to be within of the Milky Way, but not a ... References Further reading * External links * * * * * {{Portal bar, Sta ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sig07-008
Sig used as a name may refer to: *Sig (given name) *Sig, Algeria, a city on the banks of the Sig River *Sig Alert, an alert for traffic congestion in California, named after Loyd Sigmon *Sig River, a river of Algeria also known as Mekerra sig (lower case) may refer to: *sig (rune), an Armanen rune, later used for the Schutzstaffel (SS) logo *sig, the distinctive hand actions of sign language that form words; see movement (sign language) * .sig, a signature block in e-mail messaging ''sig'' as a loanword may refer to: *''sig'' (Russian), the common whitefish; see ''Coregonus'' *''Sig'' (Italian), abbreviation of ''Signore'' ("Lord") *''Sig.'' (Latin, also ''Signa'' or ''Signatura''), the "signature" section of a medical prescription, which contains directions to the patient, and the signature of the prescribing doctor *Sig. Signaling ( in R''ail transport'') the signals and associated equipment required for their operation. SIG (capitalized) may refer to: *SIG, the IATA Callsign o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Helmi Stream
The Helmi Stream is a stellar stream of the Milky Way galaxy. It started as a dwarf galaxy, now absorbed by the Milky Way as a stream. It was discovered in 1999, is formed of old stars deficient in heavy elements, and has a mass of 10 to 100 million solar masses. It was absorbed by the Milky Way some 6 to 9 billion years ago.Scientific American"Extragalactic Expat: Newfound Exoplanet Likely Came from Another Galaxy" John Matson , 18 November 2010 The stream was named after Amina Helmi, who discovered this stellar stream after noticing this group of stars all moving at the same speed and in the same direction. The Helmi Stream discovery affirmed theories that the merging of galaxies played a significant role in creating the giant structures of the Milky Way galaxy. Extragalactic planet The Helmi stream was home to the first planet purportedly of extragalactic origin, orbiting the star HIP 13044. Further analysis of radial velocity data failed to confirm the discovery. See also * ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Boötes III Stream
Boötes ( ) is a constellation in the northern sky, located between 0° and +60° declination, and 13 and 16 hours of right ascension on the celestial sphere. The name comes from la, Boōtēs, which comes from grc-gre, Βοώτης, Boṓtēs ' herdsman' or 'plowman' (literally, ' ox-driver'; from ''boûs'' 'cow'). One of the 48 constellations described by the 2nd-century astronomer Ptolemy, Boötes is now one of the 88 modern constellations. It contains the fourth-brightest star in the night sky, the orange giant Arcturus. Epsilon Boötis, or Izar, is a colourful multiple star popular with amateur astronomers. Boötes is home to many other bright stars, including eight above the fourth magnitude and an additional 21 above the fifth magnitude, making a total of 29 stars easily visible to the naked eye. History and mythology In ancient Babylon, the stars of Boötes were known as SHU.PA. They were apparently depicted as the god Enlil, who was the leader of the Babylonian ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acheron Stream
The Acheron (; grc, Ἀχέρων ''Acheron'' or Ἀχερούσιος ''Acherousios''; ell, Αχέροντας ''Acherontas'') is a river located in the Epirus region of northwest Greece. It is long, and its drainage area is . Its source is near the village Zotiko, in the southwestern part of the Ioannina regional unit, and it flows into the Ionian Sea in Ammoudia, near Parga. The Acheron also features prominently in Greek mythology, where it is often depicted as the entrance to the Greek Underworld where souls must be ferried across by Charon (although some later sources, such as Roman poets, assign this role to the river Styx). Mythology Ancient Greek mythology saw the Acheron, sometimes known as the "river of woe", as one of the five rivers of the Greek underworld. The name is of uncertain etymology. Most classical accounts, including Pausanias (10.28) and later Dante's ''Inferno'' (3.78), portray the Acheron as the entrance to the Underworld and depict Charon ferr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Orphan Stream
An orphan (from the el, ορφανός, orphanós) is a child whose parents have died. In common usage, only a child who has lost both parents due to death is called an orphan. When referring to animals, only the mother's condition is usually relevant (i.e. if the female parent has gone, the offspring is an orphan, regardless of the father's condition). Definitions Various groups use different definitions to identify orphans. One legal definition used in the United States is a minor bereft through "death or disappearance of, abandonment or desertion by, or separation or loss from, both parents". In the common use, an orphan does not have any surviving parent to care for them. However, the United Nations Children's Fund (UNICEF), Joint United Nations Programme on HIV and AIDS (UNAIDS), and other groups label any child who has lost one parent as an orphan. In this approach, a ''maternal orphan'' is a child whose mother has died, a ''paternal orphan'' is a child whose fathe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
NGC 5466
NGC 5466 is a class XII globular cluster in the constellation Boötes. Located 51,800 light years from Earth and 52,800 light years from the Galactic Center, it was discovered by William Herschel on May 17, 1784, as H VI.9. This globular cluster is unusual insofar as it contains a certain blue horizontal branch of stars, as well as being unusually metal poor like ordinary globular clusters. It is thought to be the source of a stellar stream discovered in 2006, called the ''45 Degree Tidal Stream''. This star stream is an approximately 1.4° wide star lane extending from Boötes to Ursa Major. See also * List of stellar streams This is a list of stellar streams. A stellar stream is an association of stars orbiting a galaxy that was once a globular cluster or dwarf galaxy that has now been torn apart and stretched out along its orbit by tidal forces. An exception in the ... References Further reading * * * * * * * * * * * * * * * * * External links * ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
NGC 5466 Stream
NGC 5466 is a class XII globular cluster in the constellation Boötes. Located 51,800 light years from Earth and 52,800 light years from the Galactic Center, it was discovered by William Herschel on May 17, 1784, as H VI.9. This globular cluster is unusual insofar as it contains a certain blue horizontal branch of stars, as well as being unusually metal poor like ordinary globular clusters. It is thought to be the source of a stellar stream discovered in 2006, called the ''45 Degree Tidal Stream''. This star stream is an approximately 1.4° wide star lane extending from Boötes to Ursa Major. See also * List of stellar streams This is a list of stellar streams. A stellar stream is an association of stars orbiting a galaxy that was once a globular cluster or dwarf galaxy that has now been torn apart and stretched out along its orbit by tidal forces. An exception in the ... References Further reading * * * * * * * * * * * * * * * * * External links * ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anticenter Stream
The anticenter shell or anticenter superbubble is a region near the anticenter of the Milky Way Galaxy that emits 21 cm radiation. It is located at , or l = 197°, b = +2° in galactic coordinates, near the border of the constellations Gemini and Orion. It is a supershell (a very large superbubble) within our galaxy that is spherical in shape and features jets of gas. Discovered in 1970, this galactic object has subsequently been variously classified by researchers as a spiral arm of the Milky Way in 1972, a nearby tidally-stripped dwarf galaxy in 1975, and a high-velocity cloud in 1979. The name Snickers for the anticenter shell arose from the description in 1975 by Christian Simonson, a University of Maryland astronomer who believed it to be a small "peanut" of a galaxy just outside the Milky Way. Simonson's colleagues coined the name ''Snickers'' (in reference to the American chocolate bars ''Milky Way'' and '' Snickers'') due to its proximity to the Milky Way. Less ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Canis Major Overdensity
The Canis Major Overdensity (''CMa Overdensity'') or Canis Major Dwarf Galaxy (''CMa Dwarf'') is a disputed dwarf irregular galaxy in the Local Group, located in the same part of the sky as the constellation Canis Major. The supposed small galaxy contains a relatively high percentage of red giants and is thought to contain an estimated one billion stars in all. At the time of its announcment, the Canis Major Dwarf Galaxy is classified as an irregular galaxy and is thought to be the closest neighboring galaxy to the Earth's location in the Milky Way, being located about away from the Solar System and from the Galactic Center. It has a roughly elliptical shape and is thought to contain as many stars as the Sagittarius Dwarf Elliptical Galaxy, the previous contender for closest galaxy to the Earth's location in the Milky Way, though later studies disputed this conclusion. Discovery The existence of a strong elliptical-shaped stellar overdensity was reported in November 20 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Monoceros Ring
The Monoceros Ring ''(monoceros: Greek for 'unicorn')'' is a long, complex, ring of stars that wraps around the Milky Way three times. This is proposed to consist of a stellar stream torn from the Canis Major Dwarf Galaxy by tidal forces as part of the process of merging with the Milky Way over a period of billions of years, although this view has long been disputed. The ring contains 100 million solar masses and is 200,000 light years long. The stream of stars was first reported in 2002 by astronomers conducting the Sloan Digital Sky Survey. In the course of investigating this ring of stars, and a closely spaced group of globular clusters similar to those associated with the Sagittarius Dwarf Elliptical Galaxy, they discovered the Canis Major Dwarf Galaxy. Dispute In 2006, a study using 2MASS data cast doubts on the nature of the "Ring", arguing that the data suggests that the ring is actually part of the warped galactic disc of the Milky Way. However, observations using the A ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Virgo Stream
The Virgo Stellar Stream, also known as Virgo Overdensity, is the proposed name for a stellar stream in the constellation of Virgo which was discovered in 2005. The stream is thought to be the remains of a dwarf spheroidal galaxy that is in the process of merging with the Milky Way. It is the largest galaxy visible from the Earth, in terms of the area of the night sky covered. The stream was discovered from photometric data from the Sloan Digital Sky Survey, which was used to create a three-dimensional map of the Milky Way, using the colors and brightness of certain characteristic types of stars to estimate their distance (a method known as " photometric parallax"). The first suggestion of a new galaxy in Virgo was made in 2001 from data obtained as part of the QUEST survey, which used the one-metre Schmidt telescope at the Llano del Hato National Astronomical Observatory in Venezuela to search for RR Lyrae variable stars. Five were found in a clump with a right ascension ne ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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