J/MNRAS/493/5807 G0-G3 main-sequence stars with V<15 II (Chavez+, 2020)
Supersolar metallicity in G0-G3 main-sequence stars with V<15.
II. An extension of the sample.
Chavez M., Tapia-Schiavon C., Bertone E., Lopez-Valdivia R.
<Mon. Not. R. Astron. Soc., 493, 5807-5815 (2020)>
=2020MNRAS.493.5807C 2020MNRAS.493.5807C (SIMBAD/NED BibCode)
ADC_Keywords: Stars, G-type ; Stars, fundamental ; Effective temperatures ;
Abundances ; Photometry ; Spectra, optical
Keywords: Stars: atmospheres - stars: fundamental parameters -
stars: solar-type
Abstract:
We present the spectroscopic analysis at intermediate resolution of a
new sample of 146 Sun-like stars (of spectral types G0-G3 and
luminosity class V), which complements the data set of 233 targets
previously investigated. Aimed at identifying objects with supersolar
metallicity, we conducted observations at the Observatorio Astrofisico
Guillermo Haro and derived the basic stellar atmospheric parameters,
namely the effective temperature, surface gravity, and global
metallicity, based on a set of absorption spectroscopic indices in the
wavelength region 3800-4800Å. The newly derived set of parameters
is in good agreement with previous determinations collected from
sources in the literature. Considering the full sample of our
investigation (379 stars), we also compared the effective temperatures
of stars in common (354 objects) with Gaia DR2 for which temperatures
are available, and found that, on average, our values are about 100K
higher. We show that most of the largest temperature discrepancies can
plausibly be ascribed to interstellar extinction effects on Gaia's
photometry. Finally, within the working sample we found four more
stars that present supermetallicity, one of which was previously
reported in the literature.
Description:
The original working sample, selected back in 2008 from the SIMBAD
data base (http://simbad.u-strasbg.fr/simbad/), is composed of about
1200 stellar objects that were compliant of four selection criteria,
namely objects must have spectral types between G0 and G3, a
luminosity class concordant with main-sequence (MS) stars, a visual
magnitude V<15, and a declination of δ>-10°. In this paper,
we complement the 233 stars reported in Paper I (Lopez-Valdivia et al.
2014MNRAS.444.2251L 2014MNRAS.444.2251L, Cat. J/MNRAS/444/2251) with 146 more targets
observed during 2014-2016 at the same premises and, with the exception
of the CCD camera, also the same instrumental set-up as our initial
sample. Observations were conducted at the OAGH (in the northern state
of Sonora, Mexico) with the 2.12-m telescope and the Boller and
Chivens spectrograph, equipped with an SITe 1024x1024 CCD. The grating
of 600l/mm and the slit width of 200µm provided a constant spectral
resolution of 2.5Å FWHM and a dispersion of 0.84Å/pixel along
the wavelength range between 3800 and 4800Å. As for the data set in
Paper I, we acquired at least two spectroscopic images for each star,
with total exposure times between 3min, for the brighter objects, and
about 60min for the fainter ones, to reach a typical signal-to-noise
ratio per pixel of about 40-90, computed in a window of 100Å around
4600Å.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 33 146 The sample of the observed solar analogues
table3.dat 62 146 Stellar atmospheric parameters
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See also:
J/MNRAS/444/2251 : G0-G3 main-sequence stars with V<15 (Lopez-Valdivia+, 2014)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 18 A18 --- Name Star name
20- 24 F5.2 mag Vmag V-band magnitude
26- 29 A4 --- SpType Spectral type given in Simbad as of 2019 May
31- 33 A3 --- OSpType Previous spectral classification (1)
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Note (1): In the extended sample studied in this paper, there are 19 objects
that do not accomplish the required selection criteria. They now
either ascribed a hotter or colder classification, or do not include
a luminosity class. We have searched in the literature and found that,
indeed, for 18 stars there exists a source for the previously assigned
spectral type and luminosity class and most probably the modification
corresponds to a SIMBAD upgrade in the past 11yr with more recent
spectroscopic studies.
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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- 18 A18 --- Name Star name
20- 23 I4 K Teff Effective temperature
25- 27 I3 K E_Teff Upper 1-σ error on Teff
29- 31 I3 K e_Teff Lower 1-σ error on Teff
33- 36 F4.2 [cm/s2] logg Surface gravity
38- 41 F4.2 [cm/s2] E_logg Upper 1-σ error on logg
43- 46 F4.2 [cm/s2] e_logg Lower 1-σ error on logg
48- 52 F5.2 [-] [M/H] Metallicity
54- 57 F4.2 [-] E_[M/H] Upper 1-σ error on [M/H]
59- 62 F4.2 [-] e_[M/H] Lower 1-σ error on [M/H]
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History:
From electronic version of the journal
References:
Lopez-Valdivia et al., Paper I 2014MNRAS.444.2251L 2014MNRAS.444.2251L, Cat. J/MNRAS/444/2251
(End) Ana Fiallos [CDS] 15-May-2023