2018A&A...619A..10F


C.D.S. - SIMBAD4 rel 1.7 - 2019.11.12CET23:50:58

2018A&A...619A..10F - Astronomy and Astrophysics, volume 619A, 10-10 (2018/11-1)

Chemical analysis of very metal-poor turn-off stars from SDSS-DR12.

FRANCOIS P., CAFFAU E., WANAJO S., AGUADO D., SPITE M., AOKI M., AOKI W., BONIFACIO P., GALLAGHER A.J., SALVADORI S. and SPITE F.

Abstract (from CDS):


Context. The most metal-poor stars are the relics of the early chemical evolution of the Galaxy. Their chemical composition is an important tool to constrain the nucleosynthesis in the first generation of stars. The aim is to observe a sample of extremely metal-poor star (EMP stars) candidates selected from the Sloan Digital Sky Survey Data Release 12 (SDSS DR12) and determine their chemical composition.
Aims. We obtain medium resolution spectra of a sample of six stars using the X-shooter spectrograph at the Very Large Telescope (VLT) and we used ATLAS models to compute the abundances.
Methods. Five stars of the sample have a metallicity [Fe/H] between -2.5dex and -3.2dex. We confirm the recent discovery of SDSS J002314.00+030758.0 as a star with an extremely low [Fe/H] ratio. Assuming the α-enhancement [Ca/Fe]=+0.4dex, we obtain [Fe/H]=-6.1dex.
Results. We could also determine its magnesium abundance and found that this star exhibits a very high ratio [Mg/Fe]≤+3.60dex assuming [Fe/H]=-6.13dex. We determined the carbon abundance and found A(C)=6.4dex. From this carbon abundance, this stars belongs to the lower band of the A(C)-[Fe/H] diagram.

Abstract Copyright: © ESO 2018

Journal keyword(s): stars: Population II - Galaxy: abundances - Galaxy: halo

Simbad objects: 11

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Number of rows : 11

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 J002314.00+030758.0 * 00 23 14.0024732602 +03 07 58.239152110           ~ 9 0
2 SDSS J003730.31+245750.6 * 00 37 30.31080 +24 57 50.6088           ~ 1 0
3 HE 0107-5240 Pe* 01 09 29.1554552993 -52 24 34.203535506   15.89 15.07 15.10 14.283 CEMP-no 224 0
4 SMSS J031300.36-670839.3 Pe* 03 13 00.3747490864 -67 08 39.336567558           CEMP-no 79 0
5 SDSS J113207.12-082657.3 * 11 32 07.12392 -08 26 57.3288           ~ 1 0
6 2MASS J13132688-0019415 Pe* 13 13 26.8883961320 -00 19 41.335927067           CEMP-no 24 0
7 HE 1327-2326 Pe* 13 30 05.9395582011 -23 41 49.699027289 13.761 14.01 13.55 13.50 12.803 CEMP-no 209 0
8 SDSS J144551.13-004541.3 * 14 45 51.13224 -00 45 41.3136           ~ 1 0
9 SDSS J162049.87+322323.2 * 16 20 49.87944 +32 23 23.2656           ~ 1 0
10 HE 2323-0256 Pe* 23 26 29.8073543039 -02 39 58.037206596   15.12 14.36   13.358 CEMP-no 166 0
11 SDSS J232854.99+023924.5 * 23 28 54.99744 +02 39 24.5736           ~ 1 0

    Equat.    Gal    SGal    Ecl

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2019.11.12-23:50:58

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