2005A&A...440.1153D


C.D.S. - SIMBAD4 rel 1.7 - 2019.12.08CET16:29:11

2005A&A...440.1153D - Astronomy and Astrophysics, volume 440, 1153-1159 (2005/9-4)

The age of the Galactic thin disk from Th/Eu nucleocosmochronology. III. Extended sample.

DEL PELOSO E.F., DA SILVA L., PORTO DE MELLO G.F. and ARANY-PRADO L.I.

Abstract (from CDS):

The first determination of the age of the Galactic thin disk from Th/Eu nucleocosmochronology was accomplished by us in Papers I (2005A&A...434..275D) and II (2005A&A...434..301D). The present work aimed at reducing the age uncertainty by expanding the stellar sample with the inclusion of seven new objects - an increase by 37%. A set of [Th/Eu] abundance ratios was determined from spectral synthesis and merged with the results from Paper I. Abundances for the new, extended sample were analyzed with the aid of a Galactic disk chemical evolution (GDCE) model developed by us is Paper II. The result was averaged with an estimate obtained in Paper II from a conjunction of literature data and our GDCE model, providing our final, adopted disk age TG=(8.8±1.7)Gyr with a reduction of 0.1Gyr (6%) in the uncertainty. This value is compatible with the most up-to-date white dwarf age determinations (≲10Gyr). Considering that the halo is currently presumed to be (13.5±0.7)Gyr old, our result prompts groups developing Galactic formation models to include an hiatus of (4.7±1.8)Gyr between the formation of halo and disk.

Abstract Copyright:

Journal keyword(s): Galaxy: disk - Galaxy: evolution - stars: late-type - stars: fundamental parameters - stars: abundances

VizieR on-line data: <Available at CDS (J/A+A/440/1153): table5.dat>

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 HD 1461 PM* 00 18 41.8673684261 -08 03 10.805762856   7.14 6.46     G3VFe0.5 311 1
2 BPS CS 31082-0001 Pe* 01 29 31.1311330115 -16 00 45.496485322 12.527 12.427 11.642 11.189 10.713 ~ 237 0
3 BPS CS 30306-0132 Pe* 15 14 18.9190922462 +07 27 02.682876503   13.62 12.73 12.421 11.948 ~ 30 0
4 HD 157089 PM* 17 21 07.0567914512 +01 26 34.981760941 7.60 7.59 7.01 6.46 6.14 F8VgF8mF6 233 0
5 HD 162396 PM* 17 52 52.5828939517 -41 59 47.487625525   6.74 6.20     F9VFe-0.7CH-0.4 103 0
6 HD 189567 PM* 20 05 32.7652367983 -67 19 15.228862402 6.79 6.71 6.07     G2V 191 1
7 HD 193307 PM* 20 21 41.0361307297 -49 59 57.901102060   6.82 6.28     F9V 112 0
8 * kap Del PM* 20 39 07.7860368187 +10 05 10.279480343   5.77   4.6   G2IV 182 0
9 HD 210918 PM* 22 14 38.65336 -41 22 53.9866 7.02 6.88 6.23     G2V 173 0

    Equat.    Gal    SGal    Ecl

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2019.12.08-16:29:11

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