J/MNRAS/475/5487 Stellar properties of KIC stars (Silva Aguirre+, 2018)
Confirming chemical clocks:
asteroseismic age dissection of the Milky Way disc(s).
Silva Aguirre V., Bojsen-Hansen M., Slumstrup D., Casagrande L., Kawata D.,
Ciuca I., Handberg R., Lund M.N., Mosumgaard J.R., Huber D., Johnson J.A.,
Pinsonneault M.H., Serenelli A.M., Stello D., Tayar J., Bird J.C.,
Cassisi S., Hon M., Martig M., Nissen P.E., Rix H.W., Schonrich R.,
Sahlholdt C., Trick W.H., Yu J.
<Mon. Not. R. Astron. Soc., 475, 5487-5500 (2018)>
=2018MNRAS.475.5487S 2018MNRAS.475.5487S (SIMBAD/NED BibCode)
ADC_Keywords: Stars, giant ; Stars, masses ; Stars, diameters ; Stars, ages ;
Stars, distances
Keywords: asteroseismology - stars: fundamental parameters -
stars: kinematics and dynamic - Galaxy: disc - Galaxy: evolution -
Galaxy: structure
Abstract:
Investigations of the origin and evolution of the Milky Way disc have
long relied on chemical and kinematic identifications of its
components to reconstruct our Galactic past. Difficulties in
determining precise stellar ages have restricted most studies to small
samples, normally confined to the solar neighbourhood. Here, we break
this impasse with the help of asteroseismic inference and perform a
chronology of the evolution of the disc throughout the age of the
Galaxy. We chemically dissect the Milky Way disc population using a
sample of red giant stars spanning out to 2 kpc in the solar annulus
observed by the Kepler satellite, with the added dimension of
asteroseismic ages. Our results reveal a clear difference in age
between the low- and high-α populations, which also show
distinct velocity dispersions in the V and W components. We find no
tight correlation between age and metallicity nor [α/Fe] for the
high-α disc stars. Our results indicate that this component
formed over a period of more than 2 Gyr with a wide range of [M/H] and
[α/Fe] independent of time. Our findings show that the kinematic
properties of young α-rich stars are consistent with the rest of
the high-α population and different from the low-α stars
of similar age, rendering support to their origin being old stars that
went through a mass transfer or stellar merger event, making them
appear younger, instead of migration of truly young stars formed close
to the Galactic bar.
Description:
The set of stars considered in this study are the 1989 red giants
comprising the first combined APOGEE and Kepler catalogues, in which
the Kepler spacecraft detected oscillations during its nominal
mission.
We determined stellar properties for the APOKASC sample combining the
photometric, spectroscopic, and asteroseismic observables using the
BAyesian STellar Algorithm (BASTA, Silva Aguirre et al. 2015, Cat.
J/MNRAS/452/2127, 2017, Cat. J/ApJ/835/173).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 99 1197 Stellar properties determined with BASTA for
the APOKASC sample
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See also:
V/133 : Kepler Input Catalog (Kepler Mission Team, 2009)
J/MNRAS/452/2127 : Fundamental parameters of Kepler stars
(Silva Aguirre+, 2015)
J/ApJ/835/173 : Kepler asteroseismic LEGACY sample. II.
(Silva Aguirre+, 2017)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 8 I8 --- KIC Kepler Input Catalogue Identifier
10- 14 F5.3 Msun Mass Mass
16- 20 F5.3 Msun e_Mass rms uncertainty on Mass
22- 27 F6.3 Rsun Rad Radius
29- 33 F5.3 Rsun e_Rad rms uncertainty on Rad
35- 39 F5.3 [cm/s2] logg Surface gravity
41- 45 F5.3 [cm/s2] e_logg rms uncertainty on logg
47- 52 F6.3 Gyr Age Age
54- 58 F5.3 Gyr e_Age rms uncertainty on Age
60- 66 F7.3 Lsun Lum Luminosity
68- 73 F6.3 Lsun e_Lum rms uncertainty on Lum
75- 81 F7.2 pc Dist Distance
83- 88 F6.2 pc e_Dist rms uncertainty on Dist
90- 99 F10.8 --- Prob Target selection probability
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 08-Apr-2021