J/A+A/555/A150 Physical parameters of cool solar-type stars (Tsantaki+, 2013)
Deriving precise parameters for cool solar-type stars:
optimizing the iron line list
Tsantaki M., Sousa S. G., Adibekyan V. Zh., Santos N. C., Mortier A.,
Israelian G.
<Astron. Astrophys. 555, A150 (2013)>
=2013A&A...555A.150T 2013A&A...555A.150T
ADC_Keywords: Spectroscopy ; Stars, masses ; Stars, ages ;
Effective temperatures ; Abundances, [Fe/H]
Keywords: stars: fundamental parameters - techniques: spectroscopic
Abstract:
Temperature, surface gravity, and metallicity are basic stellar
atmospheric parameters necessary to characterize a star. There are
several methods to derive these parameters and a comparison of their
results often shows considerable discrepancies, even in the restricted
group of solar-type FGK dwarfs.
We want to check the differences in temperature between the standard
spectroscopic technique based on iron lines and the infrared flux
method (IRFM). We aim to improve the description of the spectroscopic
temperatures especially for the cooler stars where the differences
between the two methods are higher, as presented in a previous work.
Our spectroscopic analysis was based on the iron excitation and
ionization balance, assuming Kurucz model atmospheres in LTE. The
abundance analysis was determined using the code MOOG. We optimized
the line list using a cool star (HD 21749) with high resolution and
high signal-to-noise spectrum, as a reference in order to check for
weak, isolated lines.
We test the quality of the new line list by re-deriving stellar
parameters for 451 stars with high resolution and signal-to-noise
HARPS spectra, that were analyzed in a previous work with a larger
line list. The comparison in temperatures between this work and the
latest IRFM for the stars in common shows that the differences for the
cooler stars are significantly smaller and more homogeneously
distributed than in previous studies for stars with temperatures below
5000K.
Description:
The stellar sample, presented in Sousa et al. 2008, Cat. J/A+A/487/373,
is composed of 451 stars as part of the HARPS high-precision GTO
program at the ESO La Silla 3.6m telescope with the objective to
detect low-mass extra-solar planets with high radial velocity accuracy
(Mayor et al. 2003Msngr.114...20M 2003Msngr.114...20M). It is mainly comprised of dwarf
FGK stars selected from a volume-limited sample of the CORALIE survey
(Udry et al. 2000, Cat. J/A+A/356/590). The spectra have a resolution
of R∼110000 and 90% of the combined spectra have S/N higher than 200.
Table 2 is the iron line list used for the spectroscopic analysis with
the atomic data as well as the corresponding EWs of the reference star
HD21749. Table 3 are the derived stellar parameters of the 451 stars.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 38 137 Iron line list and equivalent widths for HD 21749
table3.dat 75 451 Stellar parameters of the 451 stars
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See also:
J/other/Nat/486.375 : Stellar parameters of KOI stars (Buchhave+, 2012)
J/A+A/545/A32 : Chemical abundances of 1111 stars (Adibekyan+, 2012)
J/A+A/533/A141 : Stellar parameters for 582 HARPS FGK stars (Sousa+, 2011)
J/A+A/526/A99 : Metal-poor solar-type stars spectro. & masses (Sousa+, 2011)
J/A+A/530/A138 : Geneva-Copenhagen survey re-analysis (Casagrande+, 2011)
J/A+A/512/A13 : EW-Teff calibration for solar-type stars (Sousa+, 2010)
J/A+A/512/A54 : Teff and Fbol from Infrared Flux Method (Casagrande+, 2010)
J/A+A/497/563 : Chemical abundances of 451 stars (Neves+, 2009)
J/A+A/487/373 : Spectroscopic parameters of 451 HARPS-GTO stars (Sousa+, 2008)
J/ApJ/687/1264 : Age estimation for solar-type dwarfs (Mamajek+, 2008)
J/A+A/469/783 : Code for automatic determination of EW (ARES) (Sousa+, 2007)
J/MNRAS/371/879 : Effective temperatures of 215 FGK giants (Kovtyukh+, 2006)
J/MNRAS/373/13 : Lower MS stars fundamental param. (Casagrande+, 2006)
J/MNRAS/360/1345 : F- and G-type stars in solar neighbourhood (Karatas+, 2005)
J/ApJ/626/446 : Effective temperature scale of FGK stars (Ramirez+, 2005)
J/A+A/420/183 : Spectro. survey in solar neighborhood (Allende Prieto+ 2004)
J/A+A/415/1153 : [Fe/H] for 98 extra-solar planet-host stars (Santos+, 2004)
J/A+A/411/559 : Effective temperature for 181 F-K dwarfs (Kovtyukh+, 2003)
J/A+A/377/911 : Age-metallicity relation (Feltzing+, 2001)
J/A+A/356/590 : The CORALIE survey for extrasolar planets II (Udry+, 2000)
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 7 F7.2 0.1nm lambda [4508.28/6864.32] Central wavelength (Å)
12- 15 F4.2 eV EP Excitation potential
21- 26 F6.3 --- loggf Oscilator strength
28- 31 A4 --- El Element (FeI or FeII)
34- 38 F5.1 0.1pm EW [5.1/154.3] Equivalent width of
reference star HD 21749
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Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 10 A10 --- Star Star name (HD or HIP number)
12- 15 I4 K Teff [4400/6431] Effective temperature
17- 19 I3 K e_Teff [10/221] rms uncertainty on Teff
21- 24 F4.2 [cm/s2] logg [3.6/4.82] Surface gravity
26- 29 F4.2 [cm/s2] e_logg [0.02/0.48] rms uncertainty on logg
31- 34 F4.2 km/s Vt [0/2.1] Microturbulence velocity
36- 39 F4.2 km/s e_Vt [0.01/2.2] rms uncertainty on Vt
41- 45 F5.2 [Sun] [Fe/H] [-0.83/0.36] Metallicity
47- 50 F4.2 [Sun] e_[Fe/H] [0.01/0.22] rms uncertainty on [Fe/H]
52- 56 F5.3 Msun Mass [0.7/1.4]? Estimation of the stellar Mass
58- 62 F5.3 Msun e_Mass [0/0.05]? Uncertainty on the stellar Mass
64- 69 F6.3 Gyr Age [0.15/11.75]? Estimation of the stellar Age
71- 75 F5.3 Gyr e_Age [0.01/5.1]? Uncertainty on the stellar Age
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Acknowledgement:
Maria Tsantaki, <Maria.Tsantaki( at )astro.up.pt>
(End) M. Tsantaki [CAUP-Porto, Portugal] , E. Perret [CDS] 27-Jul-2013