An absolutely calibrated T eff scale from the infrared flux method. Dwarfs and subgiants

By Luca Casagrande, I. Ramírez, Jorge Meléndez, M. Bessell, Martin Asplund. 2010

400 citations recorded by the source corpus.

Various effective temperature scales have been proposed over the years. Despite much work and the high internal precision usually achieved, systematic differences of order 100 K (or more) among various scales are still present. We present an investigation based on the infrared flux method aimed at assessing the source of such discrepancies and pin down their origin. We break the impasse among different scales by using a large set of solar twins, stars which are spectroscopically and photometrically identical to the Sun, to set the absolute zero point of the effective temperature scale to within few degrees. Our newly calibrated, accurate and precise temperature scale applies to dwarfs and subgiants, from super-solar metallicities to the most metal-poor stars currently known. At solar metallicities our results validate spectroscopic effective temperature scales, whereas for [Fe/H] < −2.5 our temperatures are roughly 100 K hotter than those determined from model fits to the Balmer lines and 200 K hotter than those obtained from the excitation equilibrium of Fe lines. Empirical bolometric corrections and useful relations linking photometric indices to effective temperatures and angular diameters have been derived. Our results take full advantage of the high accuracy reached in absolute calibration in recent years and are further validated by interferometric angular diameters and space based spectrophotometry over a wide range of effective temperatures and metallicities.

Subfields: Aerospace Engineering, Astronomy and Astrophysics, Atomic and Molecular Physics, and Optics

View Paper: https://www.semanticscholar.org/paper/708d84e5fd27430ff25f0fd60d7f789b7073dac6

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Citations in the corpus

Standing on the Shoulders of Dwarfs: the Kepler Asteroseismic LEGACY Sample. II. Radii, Masses, and Ages (2016, methodology): “In the implementation considered here, the IRFM used several photometric bands to determine the bolometric flux of a star and its effective temperature in a selfconsistent manner (see Casagrande et al. 2010, 2014b, and Section 5.3 below for details).”
The Solar Twin Planet Search. I. Fundamental parameters of the stellar sample (2014, methodology): “In this work, we used the implementation described in Casagrande et al. (2010), which uses multiband optical (Johnson-Cousins) and infrared (2MASS) photometry to reconstruct the monochromatic (infrared) and bolometric flux.”
THE MOST METAL-POOR STARS. II. CHEMICAL ABUNDANCES OF 190 METAL-POOR STARS INCLUDING 10 NEW STARS WITH [Fe/H] ⩽ −3.5,, (2012, methodology): “…used the published photometry, reddenings, and metallicities, [Fe/H], together with the infrared flux method (IRFM) metallicity-dependent color-temperatue relations adopting Casagrande et al. (2010) for the dwarfs and Ramírez & Meléndez (2005) for the giants, to determine effective temperatures.”
COUNTING LOW-MASS STARS IN INTEGRATED LIGHT (2011, methodology): “For dwarfs we adopt the new Teff scale from Casagrande et al. (2008, 2010).”
REDDENING AND EXTINCTION TOWARD THE GALACTIC BULGE FROM OGLE-III: THE INNER MILKY WAY'S RV ∼ 2.5 EXTINCTION CURVE (2012, background): “The intrinsic (V − I) colors of these stars can be estimated from the measured temperatures and metallicities and the empirical [Fe/H]-color-Teff calibration of Casagrande et al. (2010).”
Calibrating gyrochronology using Kepler asteroseismic targets (2015, methodology): “Chaplin et al. (2014) used two different sets of effective temperatures: one was derived using an Infra-Red Flux Method (IRFM) calibration (Casagrande et al. 2010; Silva Aguirre et al. 2012) and the other from a recalibration of the SDSS griz filter KIC photometry by Pinsonneault et al. (2012)…”
Improvements to stellar structure models, based on a grid of 3D convection simulations. II. Calibrating the mixing-length formulation (2014, positive): “To take the temperature of a star is a non-trivial endeavour, but recent advances have been made by, e.g., Casagrande et al. (2010) and Meléndez et al. (2010) based on observations of solar twins (stars that are spectroscopically and photometrically indistinguishable from the Sun), and by Huber et…”
THE ELEVENTH AND TWELFTH DATA RELEASES OF THE SLOAN DIGITAL SKY SURVEY: FINAL DATA FROM SDSS-III (2015, methodology): “For this second phase of the MARVELS survey, temperature estimates were derived based on V − K and J − K colors following the infrared flux method of Casagrande et al. (2010), and giants were rejected based on a requirement of a minimum reduced proper motion (Collier Cameron et al. 2007) based on…”
The GALAH survey: scientific motivation (2015, methodology): “These, together with 2MASS photometry act as photometric priors for the subsequent spectroscopic analysis, e.g. using the Infrared Flux Method (Casagrande et al. 2010).”
Accurate Empirical Radii and Masses of Planets and Their Host Stars with Gaia Parallaxes (2016, methodology): “Numerous calibrations 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…”
Measuring the vertical age structure of the Galactic disc using asteroseismology and SAGA (2015, methodology): “…to couple classic and asteroseismic stellar parameters: for each target, the photometric effective temperature and metallicity, together with the asteroseismic mass, radius, surface gravity, mean density and distance, are computed (Casagrande et al. 2010; Paper I; Silva Aguirre et al. 2011, 2012).”
The California-Kepler Survey. II. Precise Physical Properties of 2025 Kepler Planets and Their Host Stars (2017, result): “However, for a G2 star, an error in J−K color of 0.02mag corresponds to the difference in Teff of ≈100 K, which is larger than the 60K precision of the CKS effective temperatures (Casagrande et al. 2010; Pecaut & Mamajek 2013).”
The Gaia-ESO Survey : radial metallicity gradients and age-metallicity relation of stars in the Milky Way disk (2014, background): “2 shows the differences between the spectroscopic and photometric temperatures for the calibration from González Hernández & Bonifacio (2009) (top panel) and for the calibration by Casagrande et al. (2010) (bottom panel).”
Ages and fundamental properties of Kepler exoplanet host stars from asteroseismology (2015, methodology): “We have determined distances to our targets combining the results of the InfraRed Flux Method (Casagrande et al. 2010) with asteroseismically determined stellar parameters c© 0000 RAS, MNRAS 000, 000–000 (Silva Aguirre et al. 2011b).”
Reconstructing the star formation history of the Milky Way disc(s) from chemical abundances (2014, methodology): “Because systematic errors on the effective temperature scale induce large errors on the derived ages (see Haywood 2006), the effective temperatures from Adibekyan et al. (2012) were also checked with the V-K-Teff scale from Casagrande et al. (2010).”
Synthetic stellar photometry – I. General considerations and new transformations for broad-band systems (2014, methodology): “The BCs calculated from MARCS models usually agree to within 0.02±0.07 mag with the values determined empirically from the IRFM for large ranges of Teff , [Fe/H], and log.”
The Second APOKASC Catalog: The Empirical Approach (2018, background): “There are modest differences, at the 30 K level, between their system and the more recent Casagrande et al. (2010) scale for dwarfs.”