HE 1219−0312
Extremely metal-poor star in the constellation Virgo
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HE 1219−0312 is an extremely metal-poor star in the constellation Virgo. The star is located at around 41,400 light-years away from Earth.[1]
| Observation data Epoch J2000 Equinox ICRS | |
|---|---|
| Constellation | Virgo |
| Right ascension | 12h 21m 34.143s[1] |
| Declination | −03° 28′ 39.64″[1] |
| Apparent magnitude (V) | 15.94[2] |
| Characteristics | |
| Evolutionary stage | Metal-poor star[citation needed] |
| Spectral type | CEMP[citation needed] |
| Astrometry | |
| Proper motion (μ) | RA: −2.817[1] mas/yr Dec.: −8.763[1] mas/yr |
| Parallax (π) | 0.0893±0.042 mas[1] |
| Distance | approx. 40,000 ly (approx. 11,000 pc) |
| Details | |
| Mass | 0.8[3] M☉ |
| Radius | 2.5[1] R☉ |
| Luminosity | 6.3[1] L☉ |
| Surface gravity (log g) | 2.05[3] cgs |
| Temperature | 5,100[3] K |
| Metallicity [Fe/H] | −2.96[4] dex |
| Other designations | |
| HE 1219−0312, 2MASS J12213413−0328396 | |
| Database references | |
| SIMBAD | data |
It is thought to be a second generation, Population II or metal-poor star ([Fe/H] = −2.96), The star was found in the sample of extremely metal-poor halo stars from the Hamburg/ESO Survey by W. Hayek and collaborators. The group's research was published in the July 2, 2009 issue of The Astrophysical Journal.[4]
Elemental abundance
The elemental abundances of two strongly r-process enhanced metal-poor stars, BPS CS29491−0069 and HE 1219−0312, were measured by the HERES project, resulting in a value of [Fe/H] = –2.96 and [r/Fe] = +1.5[clarification needed] for HE 1219−0312.[4]
The analysis based on high-quality VLT/UVES spectra and MARCS model atmosphere was detected these eighteen heavy elements in the spectrum of HE 1219−0312 with a case of Th II 4019A line.[clarification needed][4]
Radioactive dating for HE 1219−0312 with the observed thorium and rare-earth elements abundance pairs results in an age of 9.5 ± 6.0 billion years. When based on solar r-process residuals, an age of 17.6 ± 6.8 billion years is obtained. This roughly matches the typical age range for previously discovered metal-poor halo stars of 11–12 billion years.[4]