J/ApJ/889/157 Ages of FGK stars considering C and O abundances (Chen+, 2020)
Ages of dwarfs in the solar neighborhood: considering C and O enhancements.
Chen X., Ge Z., Chen Y., Bi S., Yu J., Li T., Li Y., Ferguson J W, Zhang J.,
Wu Y.
<Astrophys. J., 889, 157 (2020)>
=2020ApJ...889..157C 2020ApJ...889..157C
ADC_Keywords: Abundances; Stars, ages; Stars, masses; Space velocities
Keywords: Fundamental parameters of stars ; Chemical abundances ;
Galaxy formation ; Stellar ages ; Stellar kinematics
Abstract:
Precise stellar ages of stars are necessary to study the evolution of
the Milky Way. The age determination is significantly affected by
C and O abundances of stars due to their contribution to the overall
metallicity and opacity. On the basis of C and O abundances derived
from high-resolution observations, we determine the ages of
148 FGK-type dwarfs in the solar neighborhood by considering C and O
enhancements individually. Our results show that using C and O
enhancements individually could affect the age determination of the
high-α population, especially for stars with [O/α]>0.2dex,
making them about 1Gyr younger compared to the results using
traditional α-enhanced models. This results in a steeper slope
in the age-[α/Fe] relation for the high-α population
(changes from 0.0339±0.0075 to 0.0436±0.0086), indicating a higher
formation rate. We find no tight relation between age and [α/Fe]
or [O/Fe] in the high-α populations. The distribution of space
velocity for young α-rich stars shows that they are more likely
characterized to the low-α populations.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 84 166 The atmospheric parameters, element abundances and
typical errors of the whole sample
table5.dat 88 166 Fundamental and kinematic parameters for
the whole sample
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See also:
V/133 : Kepler Input Catalog (Kepler Mission Team, 2009)
I/347 : Distances to 1.33 billion stars in Gaia DR2 (Bailer-Jones+, 2018)
I/345 : Gaia DR2 (Gaia Collaboration, 2018)
J/A+AS/141/371 : Low-mass stars evolutionary tracks (Girardi+, 2000)
J/A+A/361/1023 : Evolution model for α-enhanced stars (Salasnich+ 2000)
J/A+A/377/911 : Age-metallicity relations (Feltzing+, 2001)
J/A+A/433/185 : Abundance analysis of 102 F and G dwarfs (Bensby+, 2005)
J/MNRAS/367/1329 : Elemental abundances for 176 stars (Reddy+, 2006)
J/A+A/512/A48 : HARPS RVs of HD125612, HD215497, HIP5158 (Lo Curto+, 2010)
J/A+A/530/A138 : Geneva-Copenhagen survey re-analysis (Casagrande+, 2011)
J/A+A/526/A112 : Radial velocities of HARPS metal-poor sample (Santos+, 2011)
J/A+A/545/A32 : Chemical abundances of 1111 FGK stars (Adibekyan+, 2012)
J/A+A/562/A71 : Abundances of solar neighbourhood dwarfs (Bensby+, 2014)
J/A+A/568/A25 : C and O abundances in stellar populations (Nissen+, 2014)
J/A+A/576/A89 : O abundances from HARPS in F-G stars (Bertran de Lis+, 2015)
J/ApJ/831/20 : C/O and Mg/Si for solar neighborhood's stars (Brewer+, 2016)
J/ApJS/225/32 : Extended abundance analysis of cool stars (Brewer+, 2016)
J/ApJ/833/225 : -2.6≤[Fe/H]≤0.2 F & G dwarfs. II. Abundances (Zhao+, 2016)
J/A+A/599/A96 : [C/H] abundances of 1110 stars (Suarez-Andres+, 2017)
J/ApJ/860/49 : Opt. spectrosc. of young α-rich stars (Matsuno+, 2018)
J/MNRAS/475/5487 : Stellar properties of KIC stars (Silva Aguirre+, 2018)
J/A+A/624/A19 : GALAH, chemodynamical analyse with TGAS (Buder+, 2019)
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 10 A10 --- ID Identifier
12- 15 I4 K Teff [4841/6600] Effective temperature
17- 19 I3 K e_Teff [25/130] Lower uncertainty in Teff
21- 23 I3 K E_Teff [25/130] Upper uncertainty in Teff
25- 28 F4.2 [cm/s2] log(g) [3.7/4.7] log surface gravity
30- 33 F4.2 [cm/s2] e_log(g) [0.03/0.09] Uncertainty in log(g)
35- 39 F5.2 [Sun] [Fe/H] [-2.5/0.5] Metallicity
41- 44 F4.2 [Sun] e_[Fe/H] [0.01/0.09] Uncertainty in [Fe/H]
46- 50 F5.2 [Sun] [C/Fe] [-0.2/0.5] log C/Fe number abundance
52- 56 F5.3 [Sun] e_[C/Fe] [0.02/0.2] Uncertainty in [C/Fe]
58- 62 F5.2 [Sun] [O/Fe] [-0.3/0.7] log O/Fe number abundance
64- 68 F5.3 [Sun] e_[O/Fe] [0.03/0.4] Uncertainty in [O/Fe]
70- 74 F5.2 [Sun] [a/Fe] [-0.06/0.4] log α/Fe number abundance
76- 78 A3 --- Ref Reference (1)
79- 84 A6 --- n_Ref "(halo)"
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Note (1): References as follows:
A12 = Adibekyan et al. (2012, J/A+A/545/A32 ; 12 occurrences)
B16 = Brewer & Fischer (2016, J/ApJ/831/20 ; 62 occurrences)
G16 = Ge et al. (2016ApJ...833..161G 2016ApJ...833..161G ; 18 occurrences)
N14 = Nissen et al. (2014, J/A+A/568/A25 ; 35 occurrences)
Z16 = Zhao et al. (2016, J/ApJ/833/225 ; 39 occurrences)
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Byte-by-byte Description of file: table5.dat
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Bytes Format Units Label Explanations
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1- 10 A10 --- ID Identifier
12- 15 F4.2 Msun Mass [0.6/1.4] Stellar mass
17- 20 F4.2 Msun e_Mass [0/0.04] Lower uncertainty in Mass
22- 25 F4.2 Msun E_Mass [0/0.06] Upper uncertainty in Mass
27- 31 F5.2 Gyr AgeCO [0.1/24.5] Age from CO-extreme model
33- 36 F4.2 Gyr e_AgeCO [0.04/8.2] Lower uncertainty in AgeCO
38- 41 F4.2 Gyr E_AgeCO [0.07/3.7] Upper uncertainty in AgeCO
43- 48 F6.2 pc Dist [6/401]? Distance
50- 56 F7.2 km/s U [-131/135]? Velocity towards the Galactic
anticenter (1)
58- 64 F7.2 km/s V [-330/28]? Velocity along galactic rotation (1)
66- 72 F7.2 km/s W [-144/93]? Velocity toward North Galactic Pole (1)
74- 78 F5.2 Gyr Age [1/22]? Age from traditional α-enhanced
model
80- 83 F4.2 Gyr e_Age [0.02/6.5]? Lower uncertainty in Agealpha
85- 88 F4.2 Gyr E_Age [0.02/2.4]? Upper uncertainty in Agealpha
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Note (1): The space velocity components are derived with respect to the
local standard of rest, adopting the standard solar motion
(U,V,W)=(-8.5,13.38,6.49)(km/s) (Coskunoglu+ 2011MNRAS.412.1237C 2011MNRAS.412.1237C).
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 13-Jul-2021