The upper limit with 90% (95%) confidence is σ_v < 2.2 (2.6) km s^(–1), the most stringent limit for any galaxy. Since one light year is about 9.5 x 10 12 km, so the diameter of the Milky Way galaxy is about 9.5 x 10 17 km in diameter. (2009), is a galaxy with a luminosity of only 900 L ☉ . 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The study also offers tantalizing clues about how iron, carbon and other elements key to human life originally formed. According to the findings of a study published online in the Astrophysical Journal, a dwarf galaxy named Segue 2 is the least massive galaxy in the known Universe. Hello and welcome to What Da Math! The name is due to the fact that it was found by the SEGUE program, the Sloan Extension for Galactic Understanding and Exploration. |. The upper limit with 90% (95%) confidence is sigma_v < 2.2 (2.6) km/s, the most stringent limit for any galaxy. Puny or not, Segue 2 is a galaxy. Bibliographic information: Evan N. Kirby et al. Segue 1 is a dwarf spheroidal galaxy or globular cluster situated in the Leo constellation and discovered in 2006 by Sloan Digital Sky Survey. … NAME Segue 2 -- Galaxy The astronomical object called NAME Segue 2 is a Galaxy: Origin of the objects types : (Ref) Object type as listed in the reference "Ref" (acronym) Object type linked to the acronym according to the original reference (2009), is a galaxy with a luminosity of only 900 L_sun. Thatâs miniscule compared to the Milky Way, which shines 20 billion times brighter. We present Keck/DEIMOS spectroscopy of 25 members of Segue 2--a threefold increase in spectroscopic sample size. We present Keck/DEIMOS spectroscopy of 25 members of Segue 2—a threefold increase in spectroscopic sample size. The least massive galaxy known to science is a collection of 1,000 stars, held together by dark matter, orbiting the Milky Way called Segue 2. Segue 2 is the least massive galaxy known.  This elongation may be caused by the tidal forces acting from the Milky Way galaxy if Segue 1 is being tidally disrupted now.. Bibliographic information: Evan N. Kirby et al. Full Record; Other Related Research It was discovered in 2009 as part of the massive Sloan Digital Sky Survey. It was discovered in 2009 as part of the massive Sloan Digital Sky Survey. âAstronomers have been searching for years for this type of dwarf galaxy, long predicted to be swarming around the Milky Way.  The metallicity of these old stars is also very low at [Fe/H] â â2.5 Â± 0.8, which means that they contain 300 times less heavy elements than the Sun.  It is located at a distance of about 23 kpc (about 75,000 light years) from the Sun and moves away from the Sun with the velocity of about 206 km/s. Researchers, in a NAOJ release, informed that the measurement accuracy of the galactic objects and the Earth achieved with interferometry technique helped study details with the same resolution as the 2300 km diameter telescope. Segue 2 is the least massive galaxy known. , Segue 1 is located in the middle of the Sagittarius Stream and at approximately the same distance from the Sun. The chemical composition of Segue 1 indicates no substantial chemical evolution has occurred since the galaxy formed, supporting the idea that it may be a surviving first galaxy that experienced only one burst of star formation, a fossil galaxy from the early universe. Segue 2 … Its small radius—of about 2.1 pc—is typical for the galactic globular clusters. 3/15 Segue 2 pushes the low-stellar mass limit of galaxy formation. Segue 2 is located in the constellation of Aries about 114,000 light-years away. We identify Segue 2 as a galaxy rather than a star cluster based on the wide dispersion in [Fe/H] (from −2.85 to −1.33) among the member stars. Segue 2, discovered by Belokurov et al.  Segue 1 has a noticeably elongated (ratio of axes ~ 2:1) shape with the half-light radius of about 30 pc. We present Keck/DEIMOS spectroscopy of 25 members of Segue 2--a threefold increase in spectroscopic sample size. The velocity dispersion is too small to be measured with our data. We identify Segue 2 as a galaxy rather than a star cluster based on the wide dispersion in [Fe/H] (from -2.85 to -1.33) among the member stars. Whereas SEGUE-1 matched shorter exposures of bright targets with long exposures of faint targets, SEGUE-2 obtains only deep pointings, as it focuses on the far reaches of our Galaxy. Segue 2, discovered by Belokurov et al., is a galaxy with a luminosity of only 900 L_☉. ApJ 770, 16; doi: 10.1088/0004-637X/770/1/16, Â© 2011-2020. Segue 2 is notable because it is such a small galaxy, holding only about 1,000 stars that orbit the Milky Way. Segue 2, discovered by an extension of the Sloan Digital Sky Survey in 2009, is putting out about as much light as 900 suns, Bullock said. The velocity dispersion is too small to be measured with our data. 2013. OSTI.GOV Journal Article: SEGUE 2: THE LEAST MASSIVE GALAXY. SEGUE 2: THE LEAST MASSIVE GALAXY. The galaxy Segue 2: boxes are ten member stars identified so far by University of California Irvine astronomers and their colleagues (Sci-News.com / Centre de DonnÃ©es astronomiques de Strasbourg / SIMBAD). Belokurov et al. It was discovered in 2009 as part of the massive Sloan Digital Sky Survey. We present Keck/DEIMOS spectroscopy of 25 members of Segue 2--a threefold increase in spectroscopic sample size.  The galaxy is located at the distance of about 35 kpc (35,000 parsecs (110,000 ly)) from the Sun and moves towards the Sun with the speed of 40 km/s.