J/ApJ/831/20 C/O and Mg/Si for solar neighborhood's stars (Brewer+, 2016)
C/O and Mg/Si ratios of stars in the solar neighborhood. Brewer J.M., Fischer D.A. <Astrophys. J., 831, 20-20 (2016)> =2016ApJ...831...20B (SIMBAD/NED BibCode)
ADC_Keywords: Stars, G-type ; Abundances ; Planets Keywords: stars: abundances; stars: solar-type; stars: statistics Abstract: The carbon-to-oxygen ratio in a protoplanetary disk can have a dramatic influence on the compositions of any terrestrial planets formed. In regions of high C/O, planets form primarily from carbonates, and in regions of low C/O, the ratio of magnesium to silicon determines the types of silicates that dominate the compositions. We present C/O and Mg/Si ratios for 852 F, G, and K dwarfs in the solar neighborhood. We find that the frequency of carbon-rich dwarfs in the solar neighborhood is <0.13% and that 156 known planet hosts in the sample follow a similar distribution as all of the stars as a whole. The cosmic distribution of Mg/Si for these same stars is broader than the C/O distribution and peaks near 1.0, with ∼60% of systems having 1≤Mg/Si<2, leading to rocky planet compositions similar to the Earth. This leaves 40% of systems that can have planets that are silicate-rich and that may have very different compositions than our own. Description: The catalog of Brewer+ (2016, J/ApJS/225/32) has abundances of 15 elements, including C, O, Mg, and Si, for more than 1600 F, G, and K stars. The stars were all observed using the HIRES instrument on the Keck telescope with the same instrumental setup. Most of the stars were observed as part of the California Planet Search (CPS) program and have a typical S/N≫100. File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file table1.dat 64 847 Stellar C/O and Mg/Si ratios (corrected version from the author)
See also: J/ApJS/225/32 : Extended abundance analysis of cool stars (Brewer+, 2016) J/A+A/584/A72 : A rocky planet at 6.5pc from the Sun (Motalebi+ 2015) J/A+A/568/A25 : C and O abundances in stellar populations (Nissen+, 2014) J/ApJ/778/132 : C and O abundances in 55 Cnc (Teske+, 2013) J/ApJ/735/41 : Carbon and oxygen abundances in FGK stars (Petigura+, 2011) J/ApJ/725/2349 : C/O vs Mg/Si of planetary systems (Delgado Mena+, 2010) J/ApJ/715/1050 : Predicted abundances for extrasolar planets. I. (Bond+, 2010) Byte-by-byte Description of file: table1.dat
Bytes Format Units Label Explanations
1- 4 I4 --- SPOCS [2/3247] SPOCS ID 6- 17 A12 --- Name Star name (1) 19- 24 F6.2 mag Vmag [0/13.7]? V band magnitude from SIMBAD (1) 26- 31 F6.3 [-] [C/H] [-1.2/0.7] Derived [C/H] abundance (1) 33- 38 F6.3 [-] [O/H] [-0.4/0.7] Derived [O/H] abundance (1) 40- 45 F6.3 [-] [Mg/H] [-0.8/0.6] Derived [Mg/H] abundance (1) 47- 52 F6.3 [-] [Si/H] [-0.7/0.6] Derived [Si/H] abundance (1) 54- 57 F4.2 --- C/O [0.04/0.7] Abundance number ratio, NC/NO (2) 59- 62 F4.2 --- Mg/Si [0.4/1.4] Abundance number ratio, NMg/NSi (2) 64 I1 --- Np [1/5]? Number of known planets
Note (1): As listed or derived in Brewer+ (2016, J/ApJS/225/32). Note (2): Based on the uncertainties provided in Brewer+ (2016, J/ApJS/225/32), the uncertainties in the C/O values are ±10% and the uncertainties in the Mg/Si values are ±3.3%.
History: From electronic version of the journal 07-Apr-2017: table 1 corrected version sent from the author (see also erratum published in 2017,ApJ,840,121) Acknowledgements: John M. Brewer [yale.edu].
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 25-Jan-2017
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