SDSS J0815+4729

SDSS J081554.26+472947.5, often abbreviated to its partial coordinates, J0815+4729, is a star with an ultra-low metallicity in the constellation of Lynx. It also has a relatively high concentration of carbon.[3] The surface of the star has temperature 6,215 K. It is at a distance of 7,500 light years (2.3 kiloparsecs) from the Sun, and is 33,000 light-years (10 kiloparsecs) from the Galactic Center.[3] Its [Fe/H] was first believed to be below –5.8 dex, making it the lowest metallicity un-evolved star detected.,[3] but was revised to -5.49 dex in 2020.[4]

SDSS J0815+4729
Observation data
Epoch J2000      Equinox J2000
Constellation Lynx
Right ascension 08h 15m 54.26778s[1]
Declination +47° 29′ 47.6013″[1]
Characteristics
Evolutionary stage main-sequence star
Spectral type F5V[2]
Astrometry
Radial velocity (Rv)-108[2] km/s
Proper motion (μ) RA: -14.257 mas/yr[1]
Dec.: -24.214 mas/yr[1]
Parallax (π)0.4089 ± 0.0685 mas[1]
Distanceapprox. 8,000 ly
(approx. 2,400 pc)
Details[3]
Surface gravity (log g)4.7 ± 0.6 cgs
Temperature6142 ± 118 K
Metallicity [Fe/H]−5.49±0.14[4] dex
Other designations
SDSS J081554.26+472947.5, Gaia DR2 931227322991970560
Database references
SIMBADdata

J0815+4729's ratio of carbon to iron, [C/Fe] is at least 5.0 dex.[3] The star is also heavily enriched in nitrogen and oxygen, originating from primordial gas cloud contaminated by single zero-metallicity supernova. The lack of heavy elements, including iron, is explained by these mostly falling back to collapsing supernova remnant.[4]

References
  1. Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv:2208.00211. Bibcode:2023A&A...674A...1G. doi:10.1051/0004-6361/202243940. S2CID 244398875. Gaia DR3 record for this source at VizieR.
  2. "SDSS J081554.26+472947.5". SIMBAD. Centre de données astronomiques de Strasbourg.
  3. Aguado, David S; Hernández, Jonay I. González; Prieto, Carlos Allende; Rebolo, Rafael (2018). "J0815+4729: A Chemically Primitive Dwarf Star in the Galactic Halo Observed with Gran Telescopio Canarias". The Astrophysical Journal. 852 (1): L20. arXiv:1712.06487. Bibcode:2018ApJ...852L..20A. doi:10.3847/2041-8213/aaa23a. S2CID 119423051.
  4. Hernández, Jonay I. González; Aguado, David S.; Prieto, Carlos Allende; Burgasser, Adam J.; Rebolo, Rafael (2020), "The Extreme CNO-enhanced Composition of the Primitive Iron-poor Dwarf Star J0815+4729", The Astrophysical Journal, 889 (1): L13, arXiv:2001.07257, Bibcode:2020ApJ...889L..13G, doi:10.3847/2041-8213/ab62ae, S2CID 210839093
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