J/MNRAS/494/1724 Effect of surface gravity on line-depth ratios (Jian+, 2020)
The effect of surface gravity on line-depth ratios in the wavelength range
0.97-1.32µm.
Jian M., Taniguchi D., Matsunaga N., Kobayashi N., Ikeda Y., Yasui C.,
Kondo S., Sameshima H., Hamano S., Fukue K., Arai A., Otsubo S.,
Kawakita H.
<Mon. Not. R. Astron. Soc., 494, 1724-1734 (2020)>
=2020MNRAS.494.1724J 2020MNRAS.494.1724J (SIMBAD/NED BibCode)
ADC_Keywords: Stars, dwarfs ; Stars, giant ; Stars, supergiant ;
Effective temperatures ; Abundances, [Fe/H] ; Spectra, infrared
Keywords: techniques: spectroscopic - stars: fundamental parameters -
supergiants - infrared: stars
Abstract:
A line-depth ratio (LDR) of two spectral lines with different
excitation potentials is expected to be correlated with the effective
temperature (Teff). It is possible to determine Teff of a star
with a precision of tens of Kelvin if dozens or hundreds of tight
LDR-Teff relations can be used. Most of the previous studies on the
LDR method were limited to optical wavelengths, but Taniguchi and
collaborators reported 81 LDR relations in the YJ band,
0.97-1.32µm, in 2018. However, with their sample of only 10 giants,
it was impossible to account for the effects of surface gravity and
metallicity on the LDRs well. Here, we investigate the gravity effect
based on YJ-band spectra of 63 stars including dwarfs, giants, and
supergiants observed with the WINERED spectrograph. We found that some
LDR-Teff relations show clear offsets between the sequence of dwarfs
and those of giants/supergiants. The difference between the ionization
potentials of the elements considered in each line pair and the
corresponding difference in the depths can, at least partly, explain
the dependency of the LDR on the surface gravity. In order to expand
the stellar parameter ranges that the LDR method can cover with high
precision, we obtained new sets of LDR-Teff relations for
solar-metal G0-K4 dwarfs and F7-K5 supergiants, respectively. The
typical precision that can be achieved with our relations is 10-30K
for both dwarfs and supergiants.
Description:
We use the YJ-band spectra of 20 dwarfs, 25 giants, and 18 supergiants
taken with WINERED. They were observed with the WIDE-mode giving the
resolution of around 28000. The spectra between 0.91 and 1.35µm are
covered with 20 echelle orders (from 42nd to 61st). The observations
were carried out with the 1.3m Araki Telescope at Koyama Observatory,
Kyoto Sangyo University in Japan from July 2015 to May 2016. A part of
the spectra of giants and supergiants were used in Matsunaga et al.
(2020ApJS..246...10M 2020ApJS..246...10M) to identify absorption lines of neutron-capture
elements.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 52 20 Stellar parameters of the dwarfs in our sample
table2.dat 50 25 Stellar parameters of the giants in our sample
table3.dat 50 18 Stellar parameters of the supergiants in our
sample
table4.dat 166 60 The offsets, ΔlogLDR, between the
LDR-Teff relations of the dwarf-supergiant,
dwarf-giant, and giant-supergiant pairs
table6.dat 164 38 Line pairs and their LDR-Teff relations for
dwarfs
table7.dat 163 69 Line pairs and their LDR-Teff relations for
supergiants
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See also:
J/A+A/411/559 : Effective temperature for 181 F-K dwarfs (Kovtyukh+, 2003)
J/A+A/427/933 : Precise temperature of F-K field dwarfs (Kovtyukh+, 2004)
J/AJ/141/90 : SEGUE stellar parameter pipeline. V. (Lee+, 2011)
J/ApJ/785/94 : Lithium abundances of a large sample of red giants
(Liu+, 2014)
J/A+A/531/A165 : MILES atmospheric parameters (Prugniel+, 2011)
J/A+A/580/A24 : Abundances in dwarfs, subgiants, and giants (da Silva+, 2015)
J/AJ/147/137 : Atmospheric parameters in luminous stars (Luck, 2014)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 8 A8 --- Name Star name (HDNNNNNN)
10- 13 I4 K Teff Effective temperature
15- 18 F4.1 K e_Teff Error on Teff
20 I1 --- r_Teff Reference for Teff (1)
22- 26 F5.2 [-] [Fe/H] Fe/H abundance ratio
28- 31 F4.2 [cm/s2] logg Surface gravity
33 I1 --- Ref Reference for [Fe/H] and logg (1)
35- 37 I3 --- S/No Signal to noise ratio of the object
39- 41 I3 --- S/Nt Signal to noise ratio of the telluric
standard
43- 52 A10 "Y:M:D" Date Observation date
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Note (1): Reference as follows:
1 = Kovtyukh et al. (2003A&A...411..559K 2003A&A...411..559K, Cat. J/A+A/411/559)
2 = Kovtyukh et al. (2004A&A...427..933K 2004A&A...427..933K, Cat. J/A+A/427/933)
3 = Lee et al. (2011AJ....141...90L 2011AJ....141...90L, Cat. J/AJ/141/90)
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 8 A8 --- Name Star name (HDNNNNNN)
10- 13 I4 K Teff Effective temperature
15- 18 F4.1 K e_Teff Error on Teff
20- 24 F5.2 [-] [Fe/H] Fe/H abundance ratio
26- 29 F4.2 [cm/s2] logg Surface gravity
31 I1 --- Ref [1/4] Reference for [Fe/H] and logg (1)
33- 35 I3 --- S/No Signal to noise ratio of the object
37- 39 I3 --- S/Nt Signal to noise ratio of the telluric
standard
41- 50 A10 "Y:M:D" Date Observation date
--------------------------------------------------------------------------------
Note (1): Reference as follows:
1 = Park et al. (2013AJ....146...73P 2013AJ....146...73P)
2 = Liu et al. (2014ApJ...785...94L 2014ApJ...785...94L, Cat. J/ApJ/785/94)
3 = Prugniel, Vauglin & Koleva (2011A&A...531A.165P 2011A&A...531A.165P, Cat. J/A+A/531/A165)
4 = da Silva, Milone & Rocha-Pinto (2015A&A...580A..24D 2015A&A...580A..24D, Cat. J/A+A/580/A24)
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Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 8 A8 --- Name Star name (HDNNNNNN)
10- 13 I4 K Teff Effective temperature
15- 18 F4.1 K e_Teff Error on Teff
20- 24 F5.2 [-] [Fe/H] Fe/H abundance ratio
26- 29 F4.2 [cm/s2] logg Surface gravity
31 I1 --- Ref [1/3] Reference for [Fe/H] and logg (1)
33- 35 I3 --- S/No Signal to noise ratio of the object
37- 39 I3 --- S/Nt Signal to noise ratio of the telluric
standard
41- 50 A10 "Y:M:D" Date Observation date
--------------------------------------------------------------------------------
Note (1): Reference as follows:
1 = Luck (2014AJ....147..137L 2014AJ....147..137L, Cat. J/AJ/147/137)
2 = Liu (2014ApJ...785...94L 2014ApJ...785...94L, Cat. J/ApJ/785/94)
3 = Lee et al. (2011AJ....141...90L 2011AJ....141...90L, Cat. J/AJ/141/90)
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Byte-by-byte Description of file: table4.dat
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Bytes Format Units Label Explanations
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1- 3 A3 --- ID Line pair ID (1)
5- 8 A4 --- Xlow Low excitation line
10- 13 A4 --- Xhigh High excitation line
15- 35 F21.18 eV DX Difference of the ionization potentials
37- 57 F21.18 --- DlogLDRds ? Offset between the LDR-Teff relations of
the dwarf-supergiant pair (2)
59- 78 F20.18 --- e_DlogLDRds ? Error on DlogLDRds
80- 100 F21.18 --- DlogLDRdg ? Offset between the LDR-Teff relations of
the dwarf-giant pair (2)
102- 121 F20.18 --- e_DlogLDRdg ? Error on DlogLDRdg
123- 145 F23.20 --- DlogLDRgs ? Offset between the LDR-Teff relations of
the giant-supergiant pair (3)
147- 166 F20.18 --- e_DlogLDRgs ? Error on DlogLDRgs
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Note (1): The line pair IDs are adopted from the Tables 4 and 5 in Taniguchi et
al. (2018MNRAS.473.4993T 2018MNRAS.473.4993T) and prefixed by 'T'
Note (2): The offsets were measured at Teff=5000K for the ds and dg pairs
Note (3): The offsets were measured at Teff=4500K for the gs pair
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Byte-by-byte Description of file: table6.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 3 A3 --- ID Line pair ID from our set of dwarf LDR-Teff
relations
5- 6 I2 --- Order Spectral order
8- 9 I2 --- NXlow Atomic number of the low excitation line
11- 14 A4 --- Xlow Low excitation line
16- 25 F10.4 0.1nm lambdalow Wavelenght of the low-excitation line
27- 32 F6.4 eV EPlow Excitation potential of the low-excitation
line
34- 35 I2 --- NXhigh Atomic number of the high excitation line
37- 40 A4 --- Xhigh High excitation line
42- 51 F10.4 0.1nm lambdahigh Wavelenght of the high-excitation line
53- 58 F6.4 eV EPhigh Excitation potential of the high-excitation
line
60- 78 F19.13 K a Slope of the LDR-Teff relation
(Teff=alogr+b)
80- 97 F18.13 K b Intercept of the LDR-Teff relation
(Teff=alogr+b)
99- 117 F19.15 K sigma Residual of the fitted LDR-Teff relation
119- 120 I2 --- N Number of stars used for calibrating the
relation
122- 142 F21.18 [-] logLDRmin LogLDR range used for calibrating the
relation (minimum value)
144- 164 F21.18 [-] logLDRmax LogLDR range used for calibrating the
relation (maximum value)
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Byte-by-byte Description of file: table7.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 3 A3 --- ID Line pair ID from our set of dwarf LDR-Teff
relations
5- 6 I2 --- Order Spectral order
8- 9 I2 --- NXlow Atomic number of the low excitation line
11- 14 A4 --- Xlow Low excitation line
16- 25 F10.4 0.1nm lambdalow Wavelenght of the low-excitation line
27- 32 F6.4 eV EPlow Excitation potential of the low-excitation
line
34- 35 I2 --- NXhigh Atomic number of the high excitation line
37- 40 A4 --- Xhigh High excitation line
42- 51 F10.4 0.1nm lambdahigh Wavelenght of the high-excitation line
53- 58 F6.4 eV EPhigh Excitation potential of the high-excitation
line
60- 78 F19.13 K a Slope of the LDR-Teff relation
(Teff=alogr+b)
80- 97 F18.13 K b Intercept of the LDR-Teff relation
(Teff=alogr+b)
99- 116 F18.14 K sigma Residual of the fitted LDR-Teff relation
118- 119 I2 --- N Number of stars used for calibrating the
relation
121- 141 F21.18 [-] logLDRmin LogLDR range used for calibrating the
relation (minimum value)
143- 163 F21.18 [-] logLDRmax LogLDR range used for calibrating the
relation (maximum value)
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History:
From electronic version of the journal
(End) Ana Fiallos [CDS] 25-May-2023