J/ApJ/791/58 C and O abundances across the Hertzsprung gap (Adamczak+, 2014)
Carbon and oxygen abundances across the Hertzsprung gap.
Adamczak J., Lambert D.L.
<Astrophys. J., 791, 58 (2014)>
=2014ApJ...791...58A 2014ApJ...791...58A (SIMBAD/NED BibCode)
ADC_Keywords: Abundances ; Stars, carbon ; Stars, atmospheres ;
Effective temperatures ; Parallaxes, trigonometric
Keywords: stars: abundances - stars: atmospheres - stars: chemically peculiar -
stars: evolution
Abstract:
We derived atmospheric parameters and spectroscopic abundances for C
and O for a large sample of stars located in the Hertzsprung gap in
the Hertzsprung-Russell diagram in order to detect chemical
peculiarities and get a comprehensive overview of the population of
stars in this evolutionary state. We have observed and analyzed
high-resolution spectra (R = 60,000) of 188 stars in the mass range
2-5 M☉ with the 2.7 m Harlan J. Smith Telescope at the McDonald
Observatory including 28 stars previously identified as Am/Ap stars.
We find that the C and O abundances of the majority of stars in the
Hertzsprung gap are in accordance with abundances derived for local
lower-mass dwarfs but detect expected peculiarities for the Am/Ap
stars. The C and O abundances of stars with Teff< 6500 K are
slightly lower than for the hotter objects but the C/O ratio is
constant in the analyzed temperature domain. No indication of an
alteration of the C and O abundances of the stars by mixing during the
evolution across the Hertzsprung gap could be found before the
homogenization of their atmospheres by the first dredge-up.
Description:
We compiled a sample of target stars from the Hipparcos catalog
(van Leeuwen 2007A&A...474..653V 2007A&A...474..653V, cat I/311). The primary selection
criterion was their position in the HRD. Effective temperatures were
calculated from B-V colors with the calibrations from Alonso et al.
(1999A&AS..140..261A 1999A&AS..140..261A) and luminosities were determined with the
Hipparcos parallaxes and V magnitudes. We selected stars with masses
between 2 and 5 M☉ by comparison with evolutionary tracks from
Bertelli et al. (2008A&A...484..815B 2008A&A...484..815B, 2009, J/A+A/508/355) and a lower
temperature limit of log (Teff)>log (3.72). The sample was furthermore
restricted to stars with small errors in their parallaxes and
declinations >-20°. We observed 188 stars with the 2.7 m Harlan J.
Smith Telescope at the McDonald Observatory. The telescope was
equipped with the Robert G. Tull Cross-Dispersed Echelle Spectrograph
(Tull et al. 1995PASP..107..251T 1995PASP..107..251T) and a Tektronix 2048x2048 pixel CCD
detector. The stars were observed in what we deem the standard (std)
setup centered on 5060 Å in order 69. This setup up was chosen in
order to cover as many of the interesting spectral lines as possible.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 49 188 Observation log of analyzed spectra
table2.dat 50 55 Spectroscopic parameters for the program stars
table3.dat 54 145 Parameters for the program stars derived
with ULySS
table4.dat 36 142 H-alpha and photometric parameters for
the program stars
table5.dat 66 161 Adopted atmospheric parameters for
the program stars
table6.dat 48 159 Masses, distances, and luminosities of
the program stars
table7.dat 32 134 C abundances for the program stars
table9.dat 33 154 O abundances for the program stars
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See also:
I/311 : Hipparcos, the New Reduction (van Leeuwen, 2007)
J/A+A/353/528 : CNO abundances in carbon stars (Ohnaka+, 2000)
J/A+A/568/A25 : C and O abundances in stellar populations (Nissen+, 2014)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 9 A9 --- HIP HIPPARCOS identifier (HIP NNNNNN)
(van Leeuwen, 2007A&A...474..653V 2007A&A...474..653V, cat I/311)
11- 18 A8 --- HD HD identifier (HD NNNNNN)
20- 23 F4.2 mag Vmag The V band magnitude
25- 28 I4 yr Obs.Y Year of the observation
30- 31 I2 "month" Obs.M Month of the observation
33- 34 I2 d Obs.D Day of the observation
36- 44 A9 s Exp Exposure time
46- 49 I4 --- SNR Signal-to-Noise Ratio
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 9 A9 --- HIP HIPPARCOS identifier (HIP NNNNNN)
(van Leeuwen, 2007A&A...474..653V 2007A&A...474..653V, cat I/311)
11- 14 I4 K Teff Effective temperature
16- 18 I3 K e_Teff The error in Teff
20- 23 F4.2 [cm/s2] log(g) Log surface gravity
25- 28 F4.2 [cm/s2] e_log(g) The error in log(g)
30- 34 F5.2 [-] [Fe/H] Metallicity
36- 39 F4.2 [-] e_[Fe/H] The error in [Fe/H]
41- 44 F4.2 km/s VTurb Microturbulent velocity
46- 50 F5.2 km/s e_VTurb The error in VTurb
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Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 9 A9 --- HIP HIPPARCOS identifier (HIP NNNNNN)
(van Leeuwen, 2007A&A...474..653V 2007A&A...474..653V, cat I/311)
11- 14 I4 K Teff Effective temperature
16- 19 I4 K e_Teff The error in Teff
21- 24 F4.2 [cm/s2] log(g) Log surface gravity
26- 29 F4.2 [cm/s2] e_log(g) The error in log(g)
31- 35 F5.2 [-] [Fe/H] Metallicity
37- 40 F4.2 [-] e_[Fe/H] The error in [Fe/H]
42- 47 F6.2 km/s sigma Dispersion velocity
49- 54 F6.2 km/s e_sigma The error in sigma
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Byte-by-byte Description of file: table4.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 9 A9 --- HIP HIPPARCOS identifier (HIP NNNNNN)
(van Leeuwen, 2007A&A...474..653V 2007A&A...474..653V, cat I/311)
11- 14 I4 K TeffHa ? Effective temperature from H-alpha
16- 17 I2 K e_TeffHa ? The error in TeffHa
19- 22 I4 K Teff Effective temperature from photometry
24- 26 I3 K e_Teff The error in Teff
28- 31 F4.2 [cm/s2] log(g) Log surface gravity
33- 36 F4.2 [cm/s2] e_log(g) The error in log(g)
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Byte-by-byte Description of file: table5.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 9 A9 --- HIP HIPPARCOS identifier (HIP NNNNNN)
(van Leeuwen, 2007A&A...474..653V 2007A&A...474..653V, cat I/311)
11- 14 I4 K Teff Effective temperature
16- 18 I3 K e_Teff The error in Teff
20 I1 --- o_Teff Number of different temperature
indicators for Teff
22- 25 F4.2 [cm/s2] log(g) ? Log surface gravity
27- 30 F4.2 [cm/s2] e_log(g) ? The error in log(g)
32- 36 F5.2 [-] [Fe/H] ? Metallicity
38- 41 F4.2 [-] e_[Fe/H] ? The error in [Fe/H]
43- 46 F4.2 km/s VTurb Turbulent velocity
48- 52 F5.2 km/s e_VTurb The error in VTurb
54- 59 F6.2 km/s Vsini ? Projected rotational velocity
61- 66 F6.2 km/s e_Vsini ? The error in Vsini
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Byte-by-byte Description of file: table6.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 9 A9 --- HIP HIPPARCOS identifier (HIP NNNNNN)
(van Leeuwen, 2007A&A...474..653V 2007A&A...474..653V, cat I/311)
11- 15 F5.2 mas plx Parallax
17- 20 F4.2 mas e_plx The error in plx
22- 24 I3 pc Dist Distance
26- 28 I3 pc e_Dist The error in Dist
30- 33 F4.2 [Lsun] logL Log luminosity
35- 38 F4.2 [Lsun] e_logL The error in logL
40- 43 F4.2 Msun Mass Mass
45- 48 F4.2 Msun e_Mass The error in Mass
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Byte-by-byte Description of file: table7.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 9 A9 --- HIP HIPPARCOS identifier (HIP NNNNNN)
(van Leeuwen, 2007A&A...474..653V 2007A&A...474..653V, cat I/311)
11- 14 F4.2 [-] C Log epsilon carbon abundance
16- 19 F4.2 [-] e_C The error in C
21- 25 F5.2 [-] [C/H] Log C/H abundance ratio
27- 30 F4.2 [-] e_[C/H] The error in [C/H]
32- 32 A1 --- Method Method used for abundance determination (1)
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Note (1): Methods used as follows : (see text for details)
l = lines;
G = CH G band model.
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Byte-by-byte Description of file: table9.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 9 A9 --- HIP HIPPARCOS identifier (HIP NNNNNN)
(van Leeuwen, 2007A&A...474..653V 2007A&A...474..653V, cat I/311)
11- 14 F4.2 [-] O Log epsilon oxygen abundance
16- 19 F4.2 [-] e_O The error in O
21- 25 F5.2 [-] [O/H] Log O/H abundance ratio
27- 30 F4.2 [-] e_[O/H] The error in [O/H]
32- 33 A2 --- Method Method used for abundance determination (1)
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Note (1): Methods used as follows : (see text for details)
l = lines;
tr = O I triplet model.
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History:
From electronic version of the journal
(End) Prepared by [AAS], Tiphaine Pouvreau [CDS] 28-Mar-2017