Astronomy:SDSS J0815+4729
Coordinates: 
08h 15m 54.268s, +47° 29′ 47.57″
| Observation data Equinox J2000.0]] (ICRS) | |
|---|---|
| Constellation | Lynx[1] |
| Right ascension | 08h 15m 54.26778s[2] |
| Declination | +47° 29′ 47.6013″[2] |
| Apparent magnitude (V) | 16.9[3] |
| Characteristics | |
| Evolutionary stage | main sequence[4] |
| Spectral type | F5V[5] |
| Astrometry | |
| Radial velocity (Rv) | −108[5] km/s |
| Proper motion (μ) | RA: −14.257[2] mas/yr Dec.: −24.214[2] mas/yr |
| Parallax (π) | 0.4089 ± 0.0685[2] mas |
| Distance | approx. 8,000 ly (approx. 2,400 pc) |
| Details | |
| Mass | 1.18[6] M☉ |
| Radius | 0.72[6] R☉ |
| Luminosity | 0.67[6] L☉ |
| Surface gravity (log g) | 4.80[6] cgs |
| Temperature | 6,142±118[4] K |
| Metallicity [Fe/H] | −5.49±0.14[7] dex |
| Other designations | |
SDSS J081554.26+472947.5, Gaia DR2 931227322991970560 | |
| Database references | |
| SIMBAD | data |
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.[4] The surface of the star has a temperature of 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.[7]
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 a collapsing supernova remnant.[7]
References
- ↑ Roman, Nancy G. (1987). "Identification of a constellation from a position". Publications of the Astronomical Society of the Pacific 99 (617): 695. doi:10.1086/132034. Bibcode: 1987PASP...99..695R Constellation record for this object at VizieR.
- ↑ 2.0 2.1 2.2 2.3 Vallenari, A. et al. (2022). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy & Astrophysics. doi:10.1051/0004-6361/202243940 Gaia DR3 record for this source at VizieR.
- ↑ Li, Haining; Tan, Kefeng; Zhao, Gang (2018). "A Catalog of 10,000 Very Metal-poor Stars from LAMOST DR3". The Astrophysical Journal Supplement Series 238 (2): 16. doi:10.3847/1538-4365/aada4a. Bibcode: 2018ApJS..238...16L.
- ↑ 4.0 4.1 4.2 4.3 4.4 4.5 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. doi:10.3847/2041-8213/aaa23a. Bibcode: 2018ApJ...852L..20A.
- ↑ 5.0 5.1 "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.
- ↑ 6.0 6.1 6.2 6.3 Stassun, Keivan G. et al. (2019). "The Revised TESS Input Catalog and Candidate Target List". The Astronomical Journal 158 (4): 138. doi:10.3847/1538-3881/ab3467. Bibcode: 2019AJ....158..138S.
- ↑ 7.0 7.1 7.2 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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