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Oldest Star
The age of the oldest known stars approaches the age of the universe, about 13.8 billion years. Some of these are among the first stars from reionization (the stellar dawn), ending the Dark Ages about 370,000 years after Big Bang. These are recognized as among the oldest individual stars observed so-far: Footnotes References {{reflist, 25em, refs= {{cite journal , first=Rennan , last=Barkana , date=1 March 2018 , title=Possible interaction between baryons and dark-matter particles revealed by the first stars , journal=Nature , volume=555 , issue=7694 , pages=71–74 , doi=10.1038/nature25791 , pmid=29493590 , arxiv=1803.06698 , bibcode=2018Natur.555...71B , s2cid=4391544 {{cite journal , last1=Cowan , first1=John J. , last2=Sneden , first2=Christopher , last3=Burles , first3=Scott , last4=Ivans , first4=Inese I. , last5=Beers , first5=Timothy C. , last6=Truran , first6=James W. , last7=Lawler , first7=James E. , ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gaia Spacecraft
''Gaia'' is a space observatory of the European Space Agency (ESA), launched in 2013 and expected to operate until 2025. The spacecraft is designed for astrometry: measuring the positions, distances and motions of stars with unprecedented precision. The mission aims to construct by far the largest and most precise 3D space catalog ever made, totalling approximately 1 billion astronomical objects, mainly stars, but also planets, comets, asteroids and quasars, among others. To study the precise position and motion of its target objects, the spacecraft monitored each of them about 70 times over the five years of the nominal mission (2014–2019), and continues to do so during its extension. The spacecraft has enough micro-propulsion fuel to operate until about November 2024. As its detectors are not degrading as fast as initially expected, the mission could therefore be extended. ''Gaia'' targets objects brighter than magnitude 20 in a broad photometric band that covers the ext ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Globular Cluster
A globular cluster is a spheroidal conglomeration of stars. Globular clusters are bound together by gravity, with a higher concentration of stars towards their centers. They can contain anywhere from tens of thousands to many millions of member stars. Their name is derived from Latin (small sphere). Globular clusters are occasionally known simply as "globulars". Although one globular cluster, Omega Centauri, was observed in antiquity and long thought to be a star, recognition of the clusters' true nature came with the advent of telescopes in the 17th century. In early telescopic observations globular clusters appeared as fuzzy blobs, leading French astronomer Charles Messier to include many of them in his catalog of astronomical objects that he thought could be mistaken for comets. Using larger telescopes, 18th-century astronomers recognized that globular clusters are groups of many individual stars. Early in the 20th century the distribution of globular clusters in the sky w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
HD 130322
HD 130322 is an 8th-magnitude star in the constellation of Virgo. It is an orange dwarf, a type of star somewhat dimmer and cooler than the Sun. Spectral type of the star is K0V. It can only be seen with binoculars or telescope. Being almost exactly on the celestial equator the star is visible everywhere in the world except for the North Pole. The star HD 130322 is named Mönch. The name was selected in the NameExoWorlds campaign by Switzerland, during the 100th anniversary of the IAU. Mönch is one of the prominent peaks of the Bernese Alps. System In 2000, an extrasolar planet was discovered orbiting the star. The star rotates at an inclination of 76 degrees relative to Earth. It has been assumed that the planet shares that inclination. But several "hot Jupiters" are known to be oblique relative to the stellar axis. See also *Lists of exoplanets These are lists of exoplanets. Most of these were discovered by the Kepler space telescope. There are an additional ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
HD 122563
HD 122563 is an extremely metal-poor red giant star, and the brightest metal-poor star in the sky. Its low heavy element content was first recognized by spectroscopic analysis in 1963. For more than twenty years it was the most metal-poor star known, being more metal-poor than any known globular cluster, and it is the most accessible example of an extreme population II or Halo star. As the most extreme metal-poor star known, HD 122563's composition was crucial in constraining theories for galactic chemical evolution; in particular, its composition peculiarities provided signposts for understanding the accumulation of heavy elements by stellar nucleosynthesis in the Galaxy. For example, it has an excess of oxygen, /Fe/nowiki> = +0.6, while the proportions of strontium, yttrium, zirconium, barium and the lanthanide elements suggest that the s-process has made no contribution to the material present in the star: in HD 122563, all these elements are products of the r-proces ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kiloparsec
The parsec (symbol: pc) is a unit of length used to measure the large distances to astronomical objects outside the Solar System, approximately equal to or (au), i.e. . The parsec unit is obtained by the use of parallax and trigonometry, and is defined as the distance at which 1 au subtends an angle of one arcsecond ( of a degree). This corresponds to astronomical units, i.e. 1\, \mathrm = 1/\tan \left( \ \mathrm \right)\, \mathrm. The nearest star, Proxima Centauri, is about from the Sun. Most stars visible to the naked eye are within a few hundred parsecs of the Sun, with the most distant at a few thousand. The word ''parsec'' is a portmanteau of "parallax of one second" and was coined by the British astronomer Herbert Hall Turner in 1913 to make calculations of astronomical distances from only raw observational data easy for astronomers. Partly for this reason, it is the unit preferred in astronomy and astrophysics, though the light-year remains prominent in popular sc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cayrel's Star
BPS CS31082-0001, named Cayrel's Star , is an old Population II star located in a distance of 2.1 kpc in the galactic halo. It belongs to the class of ultra-metal-poor stars (metallicity Fe/Hydrogen.html"_;"title="Iron.html"_;"title="/nowiki>Iron">Fe/Hydrogen">H.html" ;"title="Iron">Fe/Hydrogen.html" ;"title="Iron.html" ;"title="/nowiki>Iron">Fe/Hydrogen">H">Iron">Fe/Hydrogen.html" ;"title="Iron.html" ;"title="/nowiki>Iron">Fe/Hydrogen">H/nowiki> = -2.9), specifically the very rare subclass of neutron-capture enhanced stars. It was discovered by Tim C. Beers and collaborators with the Curtis Schmidt telescope at the Cerro Tololo Inter-American Observatory in Chile and analyzed by Roger Cayrel and collaborators. They used the Very Large Telescope ( Very Large Telescope, VLT) at the European Southern Observatory in Paranal, Chile for high-resolution optical spectroscopy to determine elemental abundances. The thorium-232 to uranium-238 ratio was used to determine ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sneden's Star
BPS CS22892-0052 (Sneden's Star) is an old population II star located at a distance of 4.7 kpc in the galactic halo. It belongs to a class of ultra- metal-poor stars ( Metallicity e/H-3.1), specifically the very rare subclass of neutron-capture ( r-process) enhanced stars. It was discovered by Tim C. Beers and collaborators with the Curtis Schmidt telescope at the Cerro Tololo Inter-American Observatory in Chile. Extended high-resolution spectroscopic observations since around 1995 (with Chris Sneden from the University of Texas at Austin as the leading observer) allowed observers to determine the abundances of 53 chemical elements in this star, as of December 2005 only second in number to the Sun. From barium (Z=56) on, all elements show the pattern of the r-process contribution to the abundances of the elements in the Solar System. Comparing the observed abundances for a stable element such as europium (Z=63) and the radioactive element thorium (Z=90) to cal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
HE 0020-1741
He or HE may refer to: Language * He (pronoun), an English pronoun * He (kana), the romanization of the Japanese kana へ * He (letter), the fifth letter of many Semitic alphabets * He (Cyrillic), a letter of the Cyrillic script called ''He'' in Ukrainian * Hebrew language (ISO 639-1 code: he) Places * He County, Anhui, China * He River, or Hejiang (贺江), a tributary of the Xi River in Guangxi and Guangdong * Hebei, abbreviated as ''HE'', a province of China (Guobiao abbreviation HE) * Hesse, abbreviated as ''HE'', a state of Germany People * He (surname), Chinese surname, sometimes transcribed Hé or Ho; includes a list of notable individuals so named * Zheng He (1371–1433), Chinese admiral * He (和) and He (合), collectively known as 和合二仙 ('' He-He er xian'', "Two immortals He"), two Taoist immortals known as the "Immortals of Harmony and Unity" * Immortal Woman He, or He Xiangu, one of the Eight Immortals of Taoism Arts, entertainment, and media * "He" (sh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
HE 0107-5240
HE0107-5240 is an extremely metal-poor Population II star, located roughly away from Earth, that has a mass of approximately 80% of the mass of the Sun. It is one of the most metal-poor stars known in our Galaxy, with a metallicity e/H= ; i.e. it has just of the metal that the Sun has. Because of its very low metallicity, it is believed to be one of the earliest Population II stars to have formed. If so, then it is also very old, with an age of roughly 13 billion years. Because the star is not completely metal-free, it does not belong to the first generation of stars (the hypothetical Population III). These stars converted the pristine hydrogen, helium, and lithium formed by the Big Bang into heavier elements, such as carbon, oxygen, and metals. The star is relatively small for a star of the early universe, which accounts for its old age: massive stars die quickly. To help explain why this star is so small, it is hypothesized it was once part of a binary star system. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SDSS J001820 , a school in Delta, British Columbia, Canada
{{disambiguation ...
SDSS may refer to: * Sloan Digital Sky Survey, a major multi-filter imaging and spectroscopic redshift survey * Social Democratic Party of Slovakia * Spatial Decision Support System, a GIS based decision aiding system * Independent Democratic Serb Party, a political party of Croatian Serbs (''Samostalna demokratska srpska stranka'' in Serbo-Croatian) * South Delta Secondary School South Delta Secondary (SDSS) is a public High school#Canada, high school in Tsawwassen, British Columbia, Canada. There are approximately 1,500 students enrolled in each grade 8 through 12 (as of 2019/2020). Graduation rates in the years 2005 to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SDSS J102915+172927
SDSS J102915+172927 or Caffau's Star is a population II star in the galactic halo, seen in the constellation Leo. It is about 13 billion years old, making it one of the oldest stars in the Galaxy. At the time of its discovery, it had the lowest metallicity of any known star. It is small (less than 0.8 solar masses), deficient in carbon, nitrogen, oxygen, and completely devoid of lithium. Because carbon and oxygen provide a fine structure cooling mechanism that is critical in the formation of low-mass stars, the origins of Caffau's Star are somewhat mysterious. It has been suggested, both for theoretical and observational reasons, that the formation of low-mass stars in the interstellar medium requires a critical metallicity somewhere between 1.5×10−8 and 1.5×10−6. The metallicity of Caffau's Star is less than 6.9×10−7. According to Schneider et al., cooling by dust rather than the fine structure lines of CII and OI may have enabled the creation of such low-mass, m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
HE 1523-0901
HE 1523-0901 is the designation given to a red giant star in the Milky Way galaxy approximately 7500 light years from Earth. It is thought to be a second generation, Population II, or metal-poor, star ( e/Hnbsp;= −2.95). The star was found in the sample of bright metal-poor halo stars from the Hamburg/ESO Survey by Anna Frebel and collaborators. The group's research was published in the May 10, 2007 issue of ''The Astrophysical Journal''. Age The star's age, as measured by ESO's Very Large Telescope, is 13.2 billion years. This makes it among the oldest stars and nearly as old as the estimated age of the universe itself (13.8 billion years as measured by Planck). The measurement uncertainty in the age estimate is 0.7 to 2.7 billion years, depending upon the assumptions made to estimate the uncertainty, although the uncertainty in the relative age of this and other stars using the same method is smaller. HE 1523-0901 is the first star whose age was determined ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
