Follow up observationes of extremely metal-poor stars identified from SDSS and LAMOST

Aguado, D.; Allende Prieto, C.; González Hernández, J. I.; Rebolo, R.
Bibliographical reference

American Astronomical Society, AAS Meeting #230, id.315.16

Advertised on:
6
2017
Number of authors
4
IAC number of authors
4
Citations
1
Refereed citations
0
Description
The most metal-poor stars in the Milky Way witnessed the early phases of formation of the Galaxy, and have chemical compositions close to the pristine mixture from Big Bang nucleosynthesis, polluted by one or very few supernovae. Here we present a program to search for and characterize new ultra metal-poor stars in the Galactic halo. These stars are extremely rare; despite significant efforts, only a handful of stars have been identified with a metallicity [Fe/H]< -5. We select candidates from SDSS and LAMOST. Dozens of them have already been observed with the ISIS spectrograph on the 4.2 m William Herschel Telescope. The most interesting objects have been confirmed with OSIRIS on the 10.4m-GTC and HRS on the 9.2 m HET. Our analysis is highly automated, and based on the FERRE code. We report the discovery of a new carbon-rich ultra metal-poor (CRUMP) dwarf star at [Fe/H]~ -5.8 with an extreme carbon over-abundance [C/Fe]~ +5.0.