Star in the constellation Aquarius
BPS CS22892-0052 (Sneden's Star ) is an oldpopulation II star located at a distance of 4.7kiloparsecs (15,000light-years ) in theMilky Way 'sgalactic halo . It belongs to a class of ultra-metal-poor stars (metallicity [Fe/H]=-3.1), specifically the very rare subclass ofneutron-capture (r-process ) enhanced stars. It was discovered byTim C. Beers and collaborators with the CurtisSchmidt telescope at theCerro Tololo Inter-American Observatory inChile . Extended high-resolutionspectroscopic observations since around 1995 (withChris Sneden from theUniversity of Texas at Austin as the leading observer) allowed observers to determine the abundances of 53chemical elements in this star, as of December 2005 only second in number to the Sun.
Frombarium (Z=56) on, all elements show the pattern of the r-process contribution to theabundances of the elements in the Solar System . Comparing the observed abundances for astable element such aseuropium (Z=63) and the radioactive elementthorium (Z=90) to calculated abundances of an r-process in a type IIsupernova explosion (as from the universities atMainz andBasel groups ofKarl-Ludwig Kratz andFriedrich-Karl Thielemann ) have allowed observers to determine the age of this star to be about 14 billion years. Similar ages have been derived for other ultra-metal-poor stars (CS31082-001 ,BD+17°3248 andHE 1523-0901 ) from thorium-to-uranium ratios.[citation needed
^ Roman, Nancy G. (1987)."Identification of a constellation from a position" .Publications of the Astronomical Society of the Pacific 99 (617): 695.Bibcode :1987PASP...99..695R .doi :10.1086/132034 Constellation record for this object atVizieR .^a b c d e Brown, A. G. A. ; et al. (Gaia collaboration ) (August 2018)."Gaia Data Release 2: Summary of the contents and survey properties" .Astronomy & Astrophysics 616 . A1.arXiv :1804.09365 Bibcode :2018A&A...616A...1G doi :10.1051/0004-6361/201833051 Gaia DR2 record for this source atVizieR .^a b c d Roederer, Ian U.; et al. (June 2014). "A Search for Stars of Very Low Metal Abundance. VI. Detailed Abundances of 313 Metal-poor Stars".The Astronomical Journal .147 (6): 57.arXiv :1403.6853 Bibcode :2014AJ....147..136R .doi :10.1088/0004-6256/147/6/136 .S2CID 119249291 . 136. ^a b c Norris, John E.; et al. (October 1997). "Extremely Metal-poor Stars. IV. The Carbon-rich Objects".The Astrophysical Journal .488 (1):350– 363.Bibcode :1997ApJ...488..350N .doi :10.1086/304695 .S2CID 121307016 . ^a b "BPS CS 22892-0052" .SIMBAD Centre de données astronomiques de Strasbourg . Retrieved2021-03-29 .^ Beers, Timothy C.; Preston, George W.; Shectman, Stephen A. (1992). "A Search for Stars of Very Low Metal Abundance. II".The Astronomical Journal .103 : 1987.Bibcode :1992AJ....103.1987B .doi :10.1086/116207 .S2CID 121564385 . ^ Anders, F.; Khalatyan, A.; Chiappini, C.; Queiroz, A. B.; Santiago, B. X.; Jordi, C.; Girardi, L.; Brown, A. G. A.; Matijevic, G.; Monari, G.; Cantat-Gaudin, T. (2019-08-01)."Photo-astrometric distances, extinctions, and astrophysical parameters for Gaia DR2 stars brighter than G = 18" .Astronomy and Astrophysics .628 : A94.arXiv :1904.11302 Bibcode :2019A&A...628A..94A .doi :10.1051/0004-6361/201935765 ISSN 0004-6361 . ^ Stassun, Keivan G.; Oelkers, Ryan J.; Paegert, Martin; Torres, Guillermo; Pepper, Joshua; De Lee, Nathan; Collins, Kevin; Latham, David W.; Muirhead, Philip S.; Chittidi, Jay; Rojas-Ayala, Bárbara (2019-10-01)."The Revised TESS Input Catalog and Candidate Target List" .The Astronomical Journal .158 (4): 138.arXiv :1905.10694 Bibcode :2019AJ....158..138S .doi :10.3847/1538-3881/ab3467 hdl :1721.1/124721 ISSN 0004-6256 .S2CID 166227927 . ^ Giribaldi, R. E.; Van Eck, S.; Merle, T.; Jorissen, A.; Krynski, P.; Planquart, L.; Valentini, M.; Chiappini, C.; Van Winckel, H. (2023). "TITANS metal-poor reference stars. II. Red giants and CEMP stars".Astronomy and Astrophysics .679 : A110.arXiv :2308.10118 Bibcode :2023A&A...679A.110G .doi :10.1051/0004-6361/202347208 . ^ Sneden, Christopher; Cowan, John J.; Lawler, James E.; Ivans, Inese I.; Burles, Scott; Beers, Timothy C.; Primas, Francesca; Hill, Vanessa; Truran, James W.; Fuller, George M.; Pfeiffer, Bernd; Kratz, Karl-Ludwig (2003). "The Extremely Metal-poor, Neutron Capture-rich Star CS 22892-052: A Comprehensive Abundance Analysis".The Astrophysical Journal .591 (2): 936.arXiv :astro-ph/0303542 Bibcode :2003ApJ...591..936S .doi :10.1086/375491 . Beers, T. C.; Preston, G. W.; Shectman, S. A. (October 1985). "A search for stars of very low metal abundance. I".The Astronomical Journal 90 :2089– 2102.Bibcode :1985AJ.....90.2089B .doi :10.1086/113917 . Beers, Timothy C.; Preston, George W.; Shectman, Stephen A. (June 1992). "A search for stars of very low metal abundance. II".The Astronomical Journal 103 :1987– 2034.Bibcode :1992AJ....103.1987B .doi :10.1086/116207 . Kratz, Karl-Ludwig; Bitouzet, Jean-Philippe; et al. (January 1993). "Isotopic r-process abundances and nuclear structure far from stability - Implications for the r-process mechanism".The Astrophysical Journal 403 :216– 238.Bibcode :1993ApJ...403..216K .doi :10.1086/172196 .ISSN 0004-637X . Sneden, Christopher; McWilliam, Andrew; et al. (August 1996)."The Extremely Metal-Poor, Neutron-Capture-Rich Star CS 22892-052: A Comprehensive Abundance Analysis" (PDF) .The Astrophysical Journal 467 : 819.Bibcode :1996ApJ...467..819S .doi :10.1086/177656 .ISSN 0004-637X . Cowan, John J.; Pfeiffer, B.; et al. (August 1999). "R-Process Abundances and Chronometers in Metal-Poor Stars".The Astrophysical Journal 521 (1):194– 205.arXiv :astro-ph/9808272 Bibcode :1999ApJ...521..194C .doi :10.1086/307512 .ISSN 0004-637X .
