2015A&A...582A..74S


C.D.S. - SIMBAD4 rel 1.7 - 2020.04.09CEST19:39:13

2015A&A...582A..74S - Astronomy and Astrophysics, volume 582A, 74-74 (2015/10-1)

Lithium abundance in a turnoff halo star on an extreme orbit.

SPITE M., SPITE F., CAFFAU E. and BONIFACIO P.

Abstract (from CDS):

The lithium abundance in turnoff stars of the old population of our Galaxy is remarkably constant in the metallicity interval -2.8<[Fe/H]←2.0, defining a plateau. The Li abundance of these turnoff stars is clearly lower than the abundance predicted by the primordial nucleosynthesis in the frame of the standard Big Bang nucleosynthesis. Different scenarios have been proposed for explaining this discrepancy, along with the very low scatter of the lithium abundance around the plateau. The recently identified very high velocity star, WISEJ0725-2351 appears to belong to the old Galactic population, and appears to be an extreme halo star on a bound, retrograde Galactic orbit. In this paper, we study the abundance ratios and, in particular the lithium abundance, in this star. The available spectra (ESO-Very Large Telescope) are analyzed and the abundances of Li, C, Na, Mg, Al, Si, Ca, Sc, Ti, Cr, Mn, Fe, Co, Ni, Sr and Ba are determined. The abundance ratios in WISEJ0725-2351 are those typical of old turnoff stars. The lithium abundance in this star is in close agreement with the lithium abundance found in the metal-poor turnoff stars located at moderate distance from the Sun. This high velocity star confirms, in an extreme case, that the very small scatter of the lithium plateau persists independent of the dynamic and kinematic properties of the stars.

Abstract Copyright:

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

VizieR on-line data: <Available at CDS (J/A+A/582/A74): table2.dat>

Status at CDS:  

Simbad objects: 8

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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 - 2020
#notes
1 BPS CS 31061-0032 Pe* 02 38 43.3010009273 +03 19 02.564348687   14.30 13.90 13.581 13.290 ~ 25 0
2 UCAC3 133-60515 PM* 07 25 43.9209656116 -23 51 17.027563740   12.48 12.06 11.98   sdF5.0: 6 0
3 HD 84937 PM* 09 48 56.09801 +13 44 39.3237 8.49 8.68 8.32 7.97 7.70 F8Vm-5 715 0
4 NGC 5139 GlC 13 26 47.28 -47 28 46.1   6.12 5.33     ~ 2971 0
5 HD 140283 Pe* 15 43 03.0967798658 -10 56 00.595803430 7.508 7.711 7.212 6.63 8.21 F9VkA5mA1 848 0
6 M 92 GlC 17 17 07.39 +43 08 09.4     6.52     ~ 1891 0
7 NGC 6397 GlC 17 40 42.09 -53 40 27.6   7.39 5.17     ~ 1784 1
8 M 54 GlC 18 55 03.33 -30 28 47.5           ~ 879 0

    Equat.    Gal    SGal    Ecl

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2020.04.09-19:39:13

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