J/A+A/647/A157 Stellar parameters of the EXPRESS sample (Soto+, 2021)
SPECIES II. Stellar parameters of the EXPRESS program giant star sample.
Soto M.G., Jones M.I., Jenkins J.S.
<Astron. Astrophys. 647, A157 (2021)>
=2021A&A...647A.157S 2021A&A...647A.157S (SIMBAD/NED BibCode)
ADC_Keywords: Fundamental catalog ; Stars, giant ; Stars, fundamental
Keywords: techniques: spectroscopic - stars: fundamental parameters -
stars: horizontal-branch
Abstract:
As part of the search for planets around evolved stars, we can
understand planet populations around significantly higher-mass stars
than the Sun on the main sequence. This population is difficult to
study any other way, particularly with radial-velocities since these
stars are too hot and rotate too fast to measure precise velocities.
Here we estimate stellar parameters for all of the giant stars from
the EXPRESS project, which aims to detect planets orbiting evolved
stars, and study their occurrence rate as a function of stellar mass.
We analyse high resolution echelle spectra of these stars, and compute
the atmospheric parameters by measuring the equivalent widths for a
set of iron lines, using an updated method implemented during this
work. Physical parameters are computed by interpolating through a grid
of stellar evolutionary models, following a procedure that carefully
takes into account the post-MS evolutionary phases. Probabilities of
the star being in the red giant branch (RBG) or the horizontal branch
(HB) are estimated from the derived distributions. Results: We find
that, out of 166 evolved stars, 101 of them are most likely in the RGB
phase, while 65 of them are in the HB phase. The mean derived mass is
1.41 and 1.87M☉ for RGB and HB stars, respectively. To validate
our method, we compared our results with interferometry and
asteroseismology studies. We find a difference in the radius with
interferometry of 1.7%. With asteroseismology, we find 2.4% difference
in logg, 1.5% in radius, 6.2% in mass, and 11.9% in age. Compared with
previous spectroscopic studies, and find a 0.5% difference in Teff, 1%
in logg, and 2% in [Fe/H]. We also find a mean mass difference with
respect to the EXPRESS original catalogue of 16%. We show that the
method presented here can greatly improve the estimates of the stellar
parameters for giant stars compared to what was presented previously.
Description:
Fundamental parameters of the giant star sample used in the EXPRESS
sample, computed using SPECIES. Some of the parameters included are
temperature, metallicity, mass, and evolutionary stage. We also
include the same analysis performed on sun spectra, as a benchmark.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tableb1.dat 37 102 Iron line list used
tableb4.dat 276 166 Results for the EXPRESS sample
tableb5.dat 160 18 Results for the Sun spectra
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See also:
J/A+A/615/A76 : Spectroscopic parameters of stars (SPECIES). I. (Soto+, 2018)
Byte-by-byte Description of file: tableb1.dat
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Bytes Format Units Label Explanations
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2- 8 F7.2 0.1nm lambda Wavelength in Angstroms
12- 15 F4.2 eV EP Excitation potential
18- 22 F5.2 [-] loggf Log of the oscillator strength
28- 31 A4 --- Ion [FeI/FeII] Name of the species
34- 37 F4.1 --- ID Identifier of the species (1)
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Note (1): The number before the decimal states the element number, and after
the decimal is the ionisation stage.
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Byte-by-byte Description of file: tableb4.dat
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Bytes Format Units Label Explanations
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1- 9 A9 --- Name Object name
11- 16 A6 --- Inst Spectrograph used
18- 25 F8.3 km/s RV Derived radial velocity of object
27- 31 F5.2 [-] [Fe/H] Metallicity
33- 37 F5.3 [-] e_[Fe/H] Uncertainty on metallicity
39- 44 F6.1 K T Temperature
46- 51 F6.3 K e_T Uncertainty on temperature
53- 57 F5.3 [cm/s2] logg Surface gravity
59- 63 F5.3 [cm/s2] e_logg Uncertainty on surface gravity
65- 69 F5.3 km/s vt Microturbulence velocity
71- 75 F5.3 km/s e_vt Uncertainty on vt
77- 78 I2 --- nFeI Number of FeI lines used
80 I1 --- nFeII Number of FeII lines used
82 I1 --- Except [1/2] Exception code (1)
84- 88 F5.3 km/s vsini Rotational velocity
90- 94 F5.3 km/s e_vsini Uncertainty on vsini
96-100 F5.3 km/s vmac Macroturbulence velocity
102-106 F5.3 km/s e_vmac Uncertainty on vmac
108-111 F4.2 Msun Mass Stellar mass
113-117 F5.3 Msun E_Mass Upper mass uncertainty
119-123 F5.3 Msun e_Mass Lower mass uncertainty
125-129 F5.2 Gyr Age Stellar age
131-135 F5.3 Gyr E_Age Upper age uncertainty
137-141 F5.3 Gyr e_Age Lower age uncertainty
143-146 F4.2 [cm/s2] trilogg Trigonometric surface gravity
148-152 F5.3 [cm/s2] E_trilogg Upper trilogg uncertainty
154-158 F5.3 [cm/s2] e_trilogg Lower trilogg uncertainty
160-164 F5.2 Rsun Radius Stellar radius
166-170 F5.3 Rsun E_Radius Upper radius uncertainty
172-176 F5.3 Rsun e_Radius Lower radius uncertainty
178-181 F4.2 [Lsun] logL Stellar luminosity
183-187 F5.3 [Lsun] E_logL Upper luminosity uncertainty
189-193 F5.3 [Lsun] e_logL Lower luminosity uncertainty
195-200 F6.2 --- eep Equivalent Evolutionary Point (2)
202-207 F6.2 --- E_eep Upper eep uncertainty (2)
209-214 F6.2 --- e_eep Lower eep uncertainty (2)
216-218 F3.1 --- PpreMS Probability of pre-main sequence (3)
220-222 F3.1 --- PMS Probability of main sequence (3)
224-228 F5.3 --- PRGB Probability of red giant branch (3)
230-234 F5.3 --- PHB Probability of horizontal branch (3)
236-238 F3.1 --- PpostHB Probability of post-HB (3)
240 A1 --- useTc [y/n] Use Tph
242 A1 --- usevt [y/n] Use fixed vt
244 A1 --- usetrilogg [y/n] Use trilogg as logg
246-251 F6.1 K Tph Temperature from photometry (4)
253-259 F7.3 K e_Tph Uncertainty on Tph (4)
261-270 A10 --- Tph-rel Relation used in Tph (4)
272-276 F5.3 mag AV Photometric extinction (5)
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Note (1): Exception code as follows:
1 = Convergence in the atmospheric parameters was reached
2 = No convergence was reached
Note (2): EEPs are points in the stellar evolution that can be identified
in different evolutionary tracks. Correspondence between EEP and
stellar evolution phase is listed in Table 2.
Note (3): The probability of each evolutionary stage is computed as
Pstate = sum (EEP_stage) / sum (N),
where EEP_stage corresponds to the number of EEP points that belong
to each evolutionary stage, and N is the total sample size.
See Sect. 3.2 of paper.
Note (4): Temperature obtained from the stellar photometric magnitudes.
The magnitudes are retrieved from several CDS catalogues
automatically, and are used together with empirical photometric
relations for the temperature. See Sect. 3.1 of paper.
Alonso1999 for Alonso et al., 1999A&AS..140..261A 1999A&AS..140..261A.
Note (5): Extinction of the object, computed using the stellar coordinates,
parallax, and the dust maps from Bovy et al. (2014ApJ...790..127B 2014ApJ...790..127B,
2016ApJ...818..130B 2016ApJ...818..130B)
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Byte-by-byte Description of file: tableb5.dat
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Bytes Format Units Label Explanations
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1- 10 A10 --- Spectrum Spectrum label (1)
12- 17 A6 --- Inst Spectrograph/Instrument (2)
19- 23 F5.2 [-] [Fe/H] Metallicity
25- 29 F5.3 [-] e_[Fe/H] Uncertainty on metallicity
31- 36 F6.1 K T Temperature
38- 43 F6.3 K e_T Uncertainty on temperature
45- 49 F5.3 [cm/s2] logg Surface gravity
51- 55 F5.3 [cm/s2] e_logg Uncertainty on surface gravity
57- 61 F5.3 km/s vt Microturbulence velocity
63- 67 F5.3 km/s e_vt Uncertainty on vt
69- 73 F5.3 km/s vsini Rotational velocity
75- 79 F5.3 km/s e_vsini Uncertainty on vsini
81- 85 F5.3 km/s vmac Macroturbulence velocity *
87- 91 F5.3 km/s e_vmac Uncertainty on vmac
93- 96 F4.2 Msun Mass Stellar mass
98-102 F5.3 Msun E_Mass Upper mass uncertainty
104-108 F5.3 Msun e_Mass Lower mass uncertainty
110-113 F4.2 Rsun Radius Stellar radius
115-119 F5.3 Rsun E_Radius Upper radius uncertainty
121-125 F5.3 Rsun e_Radius Lower radius uncertainty
127-131 F5.2 [Lsun] logL Stellar luminosity
133-137 F5.3 [Lsun] E_logL Upper luminosity uncertainty
139-143 F5.3 [Lsun] e_logL Lower luminosity uncertainty
145-148 F4.2 Gyr Age Stellar age
150-154 F5.3 Gyr E_Age Upper age uncertainty
156-160 F5.3 Gyr e_Age Lower age uncertainty
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Note (1): Spectra labeled Sun_0 to Sun_7 were taken from
Blanco-Cuaresma et al. (2014A&A...566A..98B 2014A&A...566A..98B), while the rest were obtained
through the ESO data archive
(https://www.eso.org/sci/facilities/lasilla/instruments/harps/
inst/monitoring/sun.html).
Note (2): Spectrograph/Instrument as follows:
ATLAS = Hinkle et al. (2000vnia.book.....H 2000vnia.book.....H)
NARVAL = Auriere (2003EAS.....9..105A 2003EAS.....9..105A)
UVES = Dekker et al. (2000SPIE.4008..534D 2000SPIE.4008..534D)
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Acknowledgements:
Maritza G. Soto, m.soto(at)qmul.ac.uk
References:
Soto & Jenkins, Paper I 2018A&A...615A..76S 2018A&A...615A..76S
(End) Patricia Vannier [CDS] 11-Jan-2021