HOW TO CONSTRAIN YOUR M DWARF: MEASURING EFFECTIVE TEMPERATURE, BOLOMETRIC LUMINOSITY, MASS, AND RADIUS

By A. Mann, G. Feiden, E. Gaidos, T. Boyajian, K. von Braun. 2015

348 citations recorded by the source corpus.

Precise and accurate parameters for late-type (late K and M) dwarf stars are important for characterization of any orbiting planets, but such determinations have been hampered by these stars’ complex spectra and dissimilarity to the Sun. We exploit an empirically calibrated method to estimate spectroscopic effective temperature (T eff) and the Stefan–Boltzmann law to determine radii of 183 nearby K7–M7 single stars with a precision of 2%–5%. Our improved stellar parameters enable us to develop model-independent relations between T eff or absolute magnitude and radius, as well as between color and T eff. The derived T eff–radius relation depends strongly on [Fe/H], as predicted by theory. The relation between absolute K S magnitude and radius can predict radii accurate to ≃ ?> 3%. We derive bolometric corrections to the VR C I C grizJHK S ?> and Gaia passbands as a function of color, accurate to 1%–3%. We confront the reliability of predictions from Dartmouth stellar evolution models using a Markov chain Monte Carlo to find the values of unobservable model parameters (mass, age) that best reproduce the observed effective temperature and bolometric flux while satisfying constraints on distance and metallicity as Bayesian priors. With the inferred masses we derive a semi-empirical mass–absolute magnitude relation with a scatter of 2% in mass. The best-agreement models overpredict stellar T eff values by an average of 2.2% and underpredict stellar radii by 4.6%, similar to differences with values from low-mass eclipsing binaries. These differences are not correlated with metallicity, mass, or indicators of activity, suggesting issues with the underlying model assumptions, e.g., opacities or convective mixing length.

Subfields: Astronomy and Astrophysics

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In Astronomy and Astrophysics

1. D. Charbonneau
2. Timothy Morton
3. E. Gaidos
4. J. Johnson
5. A. Mann
6. C. Dressing
7. Jon Fortney
8. D. Huber

Citations in the corpus

• STELLAR AND PLANETARY PROPERTIES OF K2 CAMPAIGN 1 CANDIDATES AND VALIDATION OF 17 PLANETS, INCLUDING A PLANET RECEIVING EARTH-LIKE INSOLATION (2015, methodology): “Flux calibration was performed using a separate pipeline described in Mann et al. (2015).”
• The stellar rotation–activity relationship in fully convective M dwarfs (2018, methodology): “This comprised calculating J-band bolometric corrections from the V − J colour, the equations of Mann et al. (2015) for calculating bolometric luminosities and calculating stellar masses from MK, and the equations of Benedict et al. (2016).”
• Revised Stellar Properties of Kepler Targets for the Q1-17 (DR25) Transit Detection Run (2016, methodology): “The classical tool to generate posterior samples is Markov Chain Monte Carlo (MCMC), which has previously been applied to stellar parameter inference using isochrones (Barclay et al. 2015; Mann et al. 2015; Morton 2015).”
• Precision Stellar Characterization of FGKM Stars using an Empirical Spectral Library (2017, methodology): “Mann et al. 2015 Mann et al. (2015) measured fundamental properties of 183 late K and M dwarfs by performing an absolute flux calibration on optical and NIR spectra using literature photometry.”
• ZODIACAL EXOPLANETS IN TIME (ZEIT). III. A SHORT-PERIOD PLANET ORBITING A PRE-MAIN-SEQUENCE STAR IN THE UPPER SCORPIUS OB ASSOCIATION (2016, methodology): “We explored mass, metallicity (for non-magnetic models), age, and distance to find an optimal fit to the observables: Teff and Fbol, using the likelihood function given in Mann et al. (2015).”
• THE SOLAR NEIGHBORHOOD. XXXVII. THE MASS–LUMINOSITY RELATION FOR MAIN-SEQUENCE M DWARFS (2016, background): “There has been considerable work on M dwarf metallicities in recent years (Rojas-Ayala et al. 2012; Önehag et al. 2012; Terrien et al. 2012; Neves et al. 2014; Mann et al. 2014, 2015; Newton et al. 2015; Lindgren & Heiter 2015).”
• CARMENES input catalogue of M dwarfs. I. Low-resolution spectroscopy with CAFOS (2015, background): “2012; Mann et al. 2014; Newton et al. 2014), or in both wavelength ranges (Mann et al. 2013, 2015).”
• They are small worlds after all: revised properties of Kepler M dwarf stars and their planets (2015, methodology): “Several candidate planets orbiting M dwarfs have already been reported (Crossfield et al. 2015; Montet et al. 2015; Mann et al. 2015b).”
• Stellar and substellar companions of nearby stars from Gaia DR2 (2018, methodology): “We adopted the masses mA = 0.708 ± 0.053 M and mB = 0.657 ± 0.057 M , estimated from the absolute K band magnitude from 2MASS and the relations by Mann et al. (2015).”
• Accurate Empirical Radii and Masses of Planets and Their Host Stars with Gaia Parallaxes (2016, neutral): “…of Teff for stars in various color/mass/age ranges have been performed (see, e.g., Casagrande et al. 2008, 2010; Boyajian et al. 2012, 2013; Mann et al. 2015), and thus while there remain systematic uncertainties, in general these uncertainties are well characterized and they are…”
• The Revised TESS Input Catalog and Candidate Target List (2019, methodology): “Stellar masses and radii were calculated using the mass–MK relations from Mann et al. (2019) and the radius–MK relations from Mann et al. (2015), both valid for 4.5<MK<10.0.”
• Revised Radii of Kepler Stars and Planets Using Gaia Data Release 2 (2018, methodology): “Therefore, we used an empirical relationship between the absolute K magnitude (MKs) and stellar radius described by Equation (4) and Table 1 of Mann et al. (2015) to compute stellar radii and hence luminosities for stars with Teff < 4100 K and MKs > 3.0 mag.”
• FUNDAMENTAL PARAMETERS AND SPECTRAL ENERGY DISTRIBUTIONS OF YOUNG AND FIELD AGE OBJECTS WITH MASSES SPANNING THE STELLAR TO PLANETARY REGIME (2015, background): “Even for these objects, there are broad regions of the model spectra that have yet to reproduce observations and so must be excluded from the fitting routine (e.g., Cushing et al. 2008b; Mann et al. 2015).”
• THE INNER EDGE OF THE HABITABLE ZONE FOR SYNCHRONOUSLY ROTATING PLANETS AROUND LOW-MASS STARS USING GENERAL CIRCULATION MODELS (2016, background): “Recent work (Boyajian et al. 2012, Boyajian et al. 2014, Terrien et al. 2015, Mann et al. 2015, Newton et al. 2015) has resulted in better stellar characterization and more accurate temperatures and radii for the M dwarfs.”
• THE K2 ECLIPTIC PLANE INPUT CATALOG (EPIC) AND STELLAR CLASSIFICATIONS OF 138,600 TARGETS IN CAMPAIGNS 1–8 (2015, background): “Hence, users are encouraged to apply empirical corrections to radii of cool dwarfs, or use the derived Teff values with empirical calibrations to estimate radii (Mann et al. 2015).”
• The Gaia–Kepler Stellar Properties Catalog. I. Homogeneous Fundamental Properties for 186,301 Kepler Stars (2020, methodology): “Therefore, we implemented the empirical Mann et al. (2015) and Mann et al. (2019) r − J–Teff , MKs– radius and MKs–mass and metallicity relations to compute Teff , stellar radius, and stellar mass, respectively.”