C/O Ratios of Stars With Transiting Hot Jupiter Exoplanets,

Teske, Johanna; Cunha, Kátia; Smith, Verne V.; Schuler, Simon C.; Griffith, C. A.

doi:10.1088/0004-637x/788/1/39

Cited by 90 publications

(90 citation statements)

References 166 publications

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“…Veyette et al (2016) . As described in , the metal-poor end of our relation has a slope similar to the linear trends of Nissen et al (2014) and Teske et al (2014); however, the linear trends do not reproduce the leveling off of C/O at higher metallicities.…”

Section: Treatment Of C and O Abundancessupporting

confidence: 49%

“…We accounted for this effect by scaling C and O abundances as functions of metallicity when generating our model grid. Spectroscopic surveys of solar neighborhood FGK stars show a tight trend between C, O, and Fe abundances (Delgado Mena et al 2010;Nissen et al 2014;Teske et al 2014;. We derived empirical relations between Fe, C, and O abundances to use when calculating our model grid based on the abundance data of , who calculated the abundances of 15 elements for 1617 FGK stars.…”

Section: Treatment Of C and O Abundancesmentioning

confidence: 99%

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A Physically Motivated and Empirically Calibrated Method to Measure the Effective Temperature, Metallicity, and Ti Abundance of M Dwarfs

Veyette

Muirhead

Mann

et al. 2017

ApJ

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The ability to perform detailed chemical analysis of Sun-like F-, G-, and K-type stars is a powerful tool with many applications, including studying the chemical evolution of the Galaxy and constraining planet formation theories. Unfortunately, complications in modeling cooler stellar atmospheres hinders similar analyses of M dwarf stars. Empirically calibrated methods to measure M dwarf metallicity from moderate-resolution spectra are currently limited to measuring overall metallicity and rely on astrophysical abundance correlations in stellar populations. We present a new, empirical calibration of synthetic M dwarf spectra that can be used to infer effective temperature, Fe abundance, and Ti abundance. We obtained high-resolution (R∼25,000), Y-band (∼1 μm) spectra of 29 M dwarfs with NIRSPEC on Keck II. Using the PHOENIX stellar atmosphere modeling code (version 15.5), we generated a grid of synthetic spectra covering a range of temperatures, metallicities, and alpha-enhancements. From our observed and synthetic spectra, we measured the equivalent widths of multiple Fe I and Ti I lines and a temperature-sensitive index based on the FeH band head. We used abundances measured from widely separated solar-type companions to empirically calibrate transformations to the observed indices and equivalent widths that force agreement with the models.

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Section: Treatment Of C and O Abundancessupporting

confidence: 49%

Section: Treatment Of C and O Abundancesmentioning

confidence: 99%

A Physically Motivated and Empirically Calibrated Method to Measure the Effective Temperature, Metallicity, and Ti Abundance of M Dwarfs

Veyette

Muirhead

Mann

et al. 2017

ApJ

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“…If we couple this result with the observational determination that most stars have C/O ratios lower than 1 (Brewer & Fischer 2016;Teske et al 2014;Nissen et al 2014), then this implies that we estimate C/O < 1 for most of the planets in the sample of Thorngren et al (2016), independent of where the planet formed as long as (1) it was formed inwards to the CO ice-line (which is the expected formation location in the core accretion scenario, see, e.g., Lissauer 1993;Armitage 2007, and references therein), (2) the envelope is well mixed with minimal metallicity gradient (expected for the masses of the planets being considered in this work, see Mordasini 0.5 1 1.5…”

Section: Discussionmentioning

confidence: 94%

Metal Enrichment Leads to Low Atmospheric C/O Ratios in Transiting Giant Exoplanets

Espinoza

Fortney

Miguel

et al. 2017

ApJL

120

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We predict the carbon-to-oxygen (C/O) ratios in the hydrogen-helium envelope and atmospheres of a sample of nearly 50 relatively cool (T eq < 1000 K) transiting gas giant planets. The method involves planetary envelope metallicity estimates that use the structure models of Thorngren et al. (2016) and the disk and planetary accretion model ofÖberg et al. (2011). We find that nearly all of these planets are strongly metal-enriched which, coupled with the fact that solid material is the main deliverer of metals in the protoplanetary disk, implies that the substellar C/O ratios of their accreted solid material dominate compared to the enhanced C/O ratio of their accreted gaseous component. We predict that these planets will have atmospheres that are typically reduced in their C/O compared to parent star values independent of the assessed formation locations, with C/O < 1 a nearly universal outcome within the framework of the model. We expect water vapor absorption features to be ubiquitous in the atmospheres of these planets, and by extension, other gas giants.

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“…This has led to speculations about the existence of exoplanets consisting of carbides and graphite instead of Earth-like silicates (Bond et al 2010). Alternative determinations of C/O in solar-type stars (Nissen 2013;Nissen et al 2014;Teske et al 2014) (2015) as seen from Fig. 11.…”

Section: Discussionmentioning

confidence: 99%

High-precision abundances of elements in solar twin stars

Nissen

2015

A&A

254

304

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Context. High-precision determinations of abundances of elements in the atmospheres of the Sun and solar twin stars indicate that the Sun has an unusually low ratio between refractory and volatile elements. This has led to the suggestion that the relation between abundance ratios, [X/Fe], and elemental condensation temperature, T C , can be used as a signature of the existence of terrestrial planets around a star. Aims. HARPS spectra with S /N 600 for 21 solar twin stars in the solar neighborhood and the Sun (observed via reflected light from asteroids) are used to determine very precise (σ ∼ 0.01 dex) differential abundances of elements in order to see how well [X/Fe] is correlated with T C and other parameters such as stellar age. Methods. Abundances of C, O, Na, Mg, Al, Si, S, Ca, Ti, Cr, Fe, Ni, Zn, and Y are derived from equivalent widths of weak and medium-strong spectral lines using MARCS model atmospheres with parameters determined from the excitation and ionization balance of Fe lines. Non-LTE effects are considered and taken into account for some of the elements. In addition, precise (σ 0.8 Gyr) stellar ages are obtained by interpolating between Yonsei-Yale isochrones in the log g -T eff diagram. Results. It is confirmed that the ratio between refractory and volatile elements is lower in the Sun than in most of the solar twins (only one star has the same [X/Fe]-T C distribution as the Sun), but for many stars, the relation between [X/Fe] and T C is not well defined.

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C/O Ratios of Stars With Transiting Hot Jupiter Exoplanets,

Cited by 90 publications

References 166 publications

A Physically Motivated and Empirically Calibrated Method to Measure the Effective Temperature, Metallicity, and Ti Abundance of M Dwarfs

A Physically Motivated and Empirically Calibrated Method to Measure the Effective Temperature, Metallicity, and Ti Abundance of M Dwarfs

Metal Enrichment Leads to Low Atmospheric C/O Ratios in Transiting Giant Exoplanets

High-precision abundances of elements in solar twin stars

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