Astronomy:J0815+4729
Coordinates: 
08h 15m 54.268s, +47° 29′ 47.57″
| Observation data Equinox J2000.0]] (ICRS) | |
|---|---|
| Constellation | Lynx |
| Right ascension | 8h 15m 54.268s[1] |
| Declination | 47° 29m 47.573s[1] |
| Characteristics | |
| Evolutionary stage | main-sequence star |
| Spectral type | F5V[2] |
| Astrometry | |
| Radial velocity (Rv) | -108[2] km/s |
| Proper motion (μ) | RA: -14.154[2] mas/yr Dec.: -24.229[2] mas/yr |
| Parallax (π) | 0.4441 ± 0.0837[3] mas |
| Distance | approx. 7,000 ly (approx. 2,300 pc) |
| Details[4] | |
| Surface gravity (log g) | 4.7 ± 0.6 cgs |
| Temperature | 6142 ± 118 K |
| Metallicity [Fe/H] | −5.49±0.14[5] dex |
| Other designations | |
SDSS J081554.26+472947.5, Gaia DR2 931227322991970560 | |
| Database references | |
| SIMBAD | data |
J0815+4729, abbreviated from SDSS J081554.26+472947.5, is a star with an ultra-low metallicity in the constellation of Lynx. It also has a relatively high concentration of carbon.[4] 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.[4] Its [Fe/H] was first believed to be below –5.8 dex, making it the lowest metallicity un-evolved star detected.,[4] but was revised to -5.49 dex in 2020.[5]
J0815+4729's ratio of carbon to iron, [C/Fe] is at least 5.0 dex.[4] 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.[5]
References
- ↑ 1.0 1.1 Ahn, C. P. (2012). "The Ninth Data Release of the Sloan Digital Sky Survey: First Spectroscopic Data from the SDSS-III Baryon Oscillation Spectroscopic Survey". The Astrophysical Journal Supplement 203 (2): 13. doi:10.1088/0067-0049/203/2/21. 21. Bibcode: 2012ApJS..203...21A.
- ↑ 2.0 2.1 2.2 2.3 "SDSS J081554.26+472947.5". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=SDSS+J081554.26%2B472947.5.
- ↑ Brown, A. G. A. (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics 616: A1. doi:10.1051/0004-6361/201833051. Bibcode: 2018A&A...616A...1G. Gaia DR2 record for this source at VizieR.
- ↑ 4.0 4.1 4.2 4.3 4.4 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: L20. doi:10.3847/2041-8213/aaa23a. Bibcode: 2018ApJ...852L..20A.
- ↑ 5.0 5.1 5.2 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, doi:10.3847/2041-8213/ab62ae, Bibcode: 2020ApJ...889L..13G
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