2017A&A...604A...9A


C.D.S. - SIMBAD4 rel 1.7 - 2020.10.30CET02:49:02

2017A&A...604A...9A - Astronomy and Astrophysics, volume 604A, 9-9 (2017/8-1)

New ultra metal-poor stars from SDSS: follow-up GTC medium-resolution spectroscopy.

AGUADO D.S., ALLENDE PRIETO C., GONZALEZ HERNANDEZ J.I., REBOLO R. and CAFFAU E.

Abstract (from CDS):

Context. The first generation of stars formed in the Galaxy left behind the chemical signatures of their nucleosynthesis in the interstellar medium, visible today in the atmospheres of low-mass stars that formed afterwards. Sampling the chemistry of those low-mass provides insight into the first stars.
Aims. We aim to increase the samples of stars with extremely low metal abundances, identifying ultra metal-poor stars from spectra with modest spectral resolution and signal-to-noise ratio (S/N). Achieving this goal involves deriving reliable metallicities and carbon abundances from such spectra.
Methods. We carry out follow-up observations of faint, V>19, metal-poor candidates selected from SDSS spectroscopy and observed with the Optical System for Imaging and low-Intermediate-Resolution Integrated Spectroscopy (OSIRIS) at GTC. The SDSS and follow-up OSIRIS spectra were analyzed using the FERRE code to derive effective temperatures, surface gravities, metallicities and carbon abundances. In addition, a well-known extremely metal-poor star has been included in our sample to calibrate the analysis methodology.
Results. We observed and analyzed five metal-poor candidates from modest-quality SDSS spectra. All stars in our sample have been confirmed as extremely metal-poor stars, in the [Fe/H]←3.3 regime. We report the recognition of J173403+644632, a carbon-enhanced ultra metal-poor dwarf star with [Fe/H]=-4.3 and [C/Fe]=+3.1.

Abstract Copyright: © ESO, 2017

Journal keyword(s): stars: abundances - stars: Population II - Galaxy: abundances - galaxies: formation - galaxies: halos - galaxies: halos

Simbad objects: 9

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Number of rows : 9

N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2020
#notes
1 SDSS J012512.51+070319.7 * 01 25 12.5048223420 +07 03 19.765179172           ~ 1 0
2 SDSS J015131.20+163944.9 * 01 51 31.2020471762 +16 39 44.994234203           ~ 2 0
3 SMSS J031300.36-670839.3 Pe* 03 13 00.3747490864 -67 08 39.336567558           CEMP-no 86 0
4 SDSS J041800.73+062308.0 * 04 18 00.7265555590 +06 23 08.110846534           ~ 1 0
5 SDSS J094708.28+461010.0 * 09 47 08.2731105675 +46 10 10.108831407           ~ 2 0
6 UCAC3 215-112497 Pe* 10 29 15.1491308300 +17 29 27.926665478         15.98 ~ 93 0
7 Wolf 1492 Pe* 13 40 02.4921790616 -00 02 18.750321114 11.601 11.832 11.451 11.184 10.892 sdF0: 263 0
8 SDSS J134157.97+513534.1 * 13 41 57.9842844319 +51 35 34.166480964           ~ 2 0
9 SDSS J173403.91+644632.9 * 17 34 03.9056765538 +64 46 32.964604499           ~ 2 0

    Equat.    Gal    SGal    Ecl

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2020.10.30-02:49:02

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