J/A+A/621/A112 Carbon and oxygen in 107 dwarf stars (Pavlenko+, 2019)
Masses, oxygen and carbon abundances in CHEPS dwarf stars.
Pavlenko Y.V., Kaminsky B.M., Jenkins J.S., Ivanyuk O.M., Jones H.R.A.,
Lyubchik Y.P.
<Astron. Astrophys. 621, A112 (2019)>
=2019A&A...621A.112P 2019A&A...621A.112P (SIMBAD/NED BibCode)
ADC_Keywords: Stars, ages ; Stars, masses ; Stars, late-type ;
Stars, fundamental ; Abundances
Keywords: planetary systems - stars: abundances - stars: carbon -
astrochemistry - line: profiles - stars: solar type
Abstract:
We report the results from the determination of stellar masses, carbon
and oxygen abundances in the atmospheres of 107 stars from the CHEPS
program. Our stars are drawn from a population with a significantly
super-solar metallicity. At least 10 of these stars are known to host
orbiting planets.
In this work, we set out to understand the behavior of carbon and
oxygen abundance in stars with different spectral classes,
metallicities and Vsini, within the metal-rich stellar population.
Masses of these stars were determined using the data from Gaia DR2
release. The oxygen and carbon abundances were determined by fitting
the absorption lines. Oxygen abundances were determined by fits to the
6300.304Å OI line, and for the determination of the carbon
abundances we used 3 lines of the CI atom and 12 lines of C2
molecule for the determination of carbon abundances.
We determine masses and abundances of 107 CHEPS stars. There is no
evidence that the [C/O] ratio depends on V sin i or the mass of the
star, within our constrained range of masses, i.e.
0.82<M*/M☉<1.5 and metallicities -0.27<[Fe/H]<+0.39 and we
confirm that metal-rich dwarf stars with planets are more carbon-rich
in comparison with non-planet host stars, with a statistical
significance of 96%.
We find tentative evidence that there is a slight offset to lower
abundance and a greater dispersion in oxygen abundances relative to
carbon, and interpret this as potentially arising from the production
of the oxygen being more effective at more metal-poor epochs. We also
find evidence that for lower mass star's the angular momentum loss
in star's with planets as measured by Vsini is steeper than
star's without planets. In general, we find that the fast rotators
(Vsini>5km/s) are massive stars.
Description:
We used the observed spectra obtained in the framework of the
Calan-Hertfordshire Extrasolar Planet Search (CHEPS) programme
(Jenkins et al., 2009ApJ...704..975J 2009ApJ...704..975J, Cat. J/ApJ/704/975).
All stars in our work were observed with the HARPS spectrograph (Mayor
et al., 2003Msngr.114...20M 2003Msngr.114...20M) at a resolving power of 115,000, and
since the spectra were taken as part of the CHEPS programme, whose
primary goal is the detection of small planets orbiting these stars,
the S/N of the spectra are all over 100 at a wavelength of 6000Å.
The 107 stars in this work are primary targets for CHEPS.
Carbon and Oxygen in the CHEPS stars. Cases of the problematic
determination of oxygen abundance due to the strong blending
6300.304Å OI line by telluric lines are marked by (*). The oxygen
abundances determined by visual comparison of computed and observed
spectra are marked by (+).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table5.dat 91 107 Parameters and abundances for all target stars
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See also:
J/MNRAS/468/4151I : Spectroscopic properties for 107 stars (Ivanyuk+, 2017)
Byte-by-byte Description of file: table5.dat
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Bytes Format Units Label Explanations
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1- 4 A4 --- Type SWP for stars with confirmed planets,
NSWP for stars with no confirmed planets
6- 15 A10 --- Name Object name
18- 21 I4 K Teff Effective temperature
25- 28 F4.2 [cm/s2] logg Surface gravity
32- 34 F3.1 km/s Vt Microturbulent velocity
38- 40 F3.1 km/s Vsini Projected rotational velocity
44- 48 F5.3 [Sun] Mass Mass in solar units (Gaia DR2)
52- 56 F5.3 [Sun] Lum Luminosity in solar units (Gaia DR2)
59- 62 F4.1 Gyr Age Age according to MIST evolutionary tracks
65- 69 F5.2 [Sun] [Fe/H] Neutral iron abundance (1)
72- 77 F6.3 [Sun] [C/H] Neutral carbon abundance (1)
79- 83 F5.3 [Sun] e_[C/H] Uncertainty of neutral carbon abundance
86- 90 F5.2 [Sun] [O/H] Neutral oxygen abundance (1)
91 A1 --- Flag [*+] Flag (2)
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Note (1): The reference solar scale was taken from Anders & Grevesse
(1989, Geochim. Cosmochim. Acta, 53, 197).
Note (2): Flag as follows:
* = problematic determination of oxygen abundance due to the for strong
blending 6300.304Å OI line by telluric lines
+ = oxygen abundances determined by visual comparison of computed and
observed spectra
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Acknowledgements:
Yakiv V. Pavlenko, email2yp(at)gmail.com
(End) Yakiv V. Pavlenko [MAO NAS, Ukraine], Patricia Vannier [CDS] 23-Nov-2018