2012A&A...542A..51C


Query : 2012A&A...542A..51C

2012A&A...542A..51C - Astronomy and Astrophysics, volume 542A, 51-51 (2012/6-1)

A primordial star in the heart of the Lion.

CAFFAU E., BONIFACIO P., FRANCOIS P., SPITE M., SPITE F., ZAGGIA S., LUDWIG H.-G., STEFFEN M., MASHONKINA L., MONACO L., SBORDONE L., MOLARO P., CAYREL R., PLEZ B., HILL V., HAMMER F. and RANDICH S.

Abstract (from CDS):

The discovery and chemical analysis of extremely metal-poor stars permit a better understanding of the star formation of the first generation of stars and of the Universe emerging from the Big Bang. We report the study of a primordial star situated in the centre of the constellation Leo (SDSSJ102915+172927). The star, selected from the low-resolution spectrum of the Sloan Digital Sky Survey, was observed at intermediate (with X-Shooter at VLT) and at high spectral resolution (with UVES at VLT). The stellar parameters were derived from the photometry. The standard spectroscopic analysis based on 1D ATLAS models was completed by applying 3D and non-LTE corrections. An iron abundance of [Fe/H] = -4.89 makes SDSSJ102915+172927 one of the lowest [Fe/H] stars known. However, the absence of measurable C and N enhancements indicates that it has the lowest metallicity, Z≤7.40x10–7 (metal-mass fraction), ever detected. No oxygen measurement was possible. The discovery of SDSSJ102915+172927 highlights that low-mass star formation occurred at metallicities lower than previously assumed. Even lower metallicity stars may yet be discovered, with a chemical composition closer to the composition of the primordial gas and of the first supernovae.

Abstract Copyright:

Journal keyword(s): stars: abundances - stars: Population II - stars: Population III - stars: formation - Galaxy: evolution - cosmology: observations

Simbad objects: 8

goto Full paper

goto View the references in ADS

Number of rows : 8
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2022
#notes
1 SB 44 SB* 00 07 37.5160975025 -35 31 17.710203728   13.23 12.76 12.76   sdF 79 0
2 HE 0107-5240 Pe* 01 09 29.1554552993 -52 24 34.203535506   15.89 15.07 15.10 14.283 CEMP-no 232 0
3 * bet CMa bC* 06 22 41.9853527 -17 57 21.307352 0.77 1.73 1.97 2.11 2.35 B1II-III 695 0
4 * eta Leo * 10 07 19.9518606 +16 45 45.580270 3.17 3.39 3.41 3.32 3.35 A0Ib 326 0
5 UCAC3 215-112497 Pe* 10 29 15.1491308300 +17 29 27.926665478         15.98 ~ 97 0
6 * rho Leo s*b 10 32 48.6716770 +09 18 23.709445 2.780 3.720 3.870 3.90 4.06 B1Iab 517 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 223 0
8 NAME Galactic Center gam 17 45 39.60213 -29 00 22.0000           ~ 12565 0

To bookmark this query, right click on this link: simbad:objects in 2012A&A...542A..51C and select 'bookmark this link' or equivalent in the popup menu


2021.12.07-22:57:33

© Université de Strasbourg/CNRS

    • Contact