Accurate fundamental parameters for lower main‐sequence stars

By Luca Casagrande, L. Portinari, Chris Flynn. 2006

153 citations recorded by the source corpus.

We derive an empirical effective temperature and bolometric luminosity calibration for G and K dwarfs, by applying our own implementation of the Infrared Flux Method to multiband photometry. Our study is based on 104 stars for which we have excellent BV(RI)CJHKS photometry, excellent parallaxes and good metallicities. Colours computed from the most recent synthetic libraries (ATLAS9 and MARCS) are found to be in good agreement with the empirical colours in the optical bands, but some discrepancies still remain in the infrared. Synthetic and empirical bolometric corrections also show fair agreement. A careful comparison to temperatures, luminosities and angular diameters obtained with other methods in the literature shows that systematic effects still exist in the calibrations at the level of a few per cent. Our Infrared Flux Method temperature scale is 100-K hotter than recent analogous determinations in the literature, but is in agreement with spectroscopically calibrated temperature scales and fits well the colours of the Sun. Our angular diameters are typically 3 per cent smaller when compared to other (indirect) determinations of angular diameter for such stars, but are consistent with the limb-darkening corrected predictions of the latest 3D model atmospheres and also with the results of asteroseismology. Very tight empirical relations are derived for bolometric luminosity, effective temperature and angular diameter from photometric indices. We find that much of the discrepancy with other temperature scales and the uncertainties in the infrared synthetic colours arise from the uncertainties in the use of Vega as the flux calibrator. Angular diameter measurements for a well-chosen set of G and K dwarfs would go a long way to addressing this problem.

Subfields: Astronomy and Astrophysics, Instrumentation, Statistical and Nonlinear Physics

View Paper: https://www.semanticscholar.org/paper/25dee8e8903673615545e3addca6e0d4ab39fede

How researchers see this paper

The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

In Astronomy and Astrophysics

In Instrumentation

In Statistical and Nonlinear Physics

Citations in the corpus

Spectroscopic parameters for 451 stars in the HARPS GTO planet search program - Stellar [Fe/H] and the frequency of exo-Neptunes (2008, methodology): “For 66 stars in the HARPS GTO sample we obtained accurate Johnson–CousinsBV(RI)C colors from the General Catalogue of Photometric Data (Mermilliod et al. 1997) and JHKS from 2MASS, and executed the IRFM as described in Casagrande et al. (2006).”
THE RADIAL VELOCITY EXPERIMENT (RAVE): FIFTH DATA RELEASE (2013, methodology): “Here we adopt an updated version of the IRFM implementation described in Casagrande et al. (2006) and Casagrande et al. (2010) which has been validated against interferometric angular diameters (Casagrande et al. 2014) and combines APASS BV g′r′i′ together with 2MASS JHKs to recover bolometric and…”
HAT-P-11b: A SUPER-NEPTUNE PLANET TRANSITING A BRIGHT K STAR IN THE KEPLER FIELD (2009, methodology): “We also ran the Ramı́rez & Meléndez (2005) and Casagrande et al. (2006) temperature calibrations in reverse to back out the B−V required to produce the SME temperature.”
An absolutely calibrated T eff scale from the infrared flux method. Dwarfs and subgiants (2010, methodology): “Given the large scatter, these numbers are still consistent with the mean differences inTeff andFBol from these two studies (Section 2.4), however, we would expect our diameters to be roughly smaller by 3 %, our fluxes brighter by 1 % and ourTeff hotter by 100 K (see also Casagrande et al. 2006).”
INTRINSIC COLORS, TEMPERATURES, AND BOLOMETRIC CORRECTIONS OF PRE-MAIN-SEQUENCE STARS (2013, background): “…of the adopted Teff , including Balona (1994); Bertone et al. (2004); Flower (1996); Bessell et al. (1998); Masana et al. (2006); Schmidt-Kaler (1982); Code et al. (1976); Casagrande et al. (2006, 2008, 2010); Lanz & Hubeny (2007); Vacca et al. (1996); Lanz & Hubeny (2003)14 where they applicable.”
Evolutionary stellar population synthesis with MILES – I. The base models and a new line index system (2010, result): “However, inspired by this work we decided to compare our stellar parameters with those from several recently published works, e.g., González-Hernández & Bonifacio (2009), Casagrande et al. (2006), Ramı́rez & Meléndez (2005), to see if our parameters should be corrected.”
A new implementation of the infrared flux method using the 2MASS catalogue (2009, methodology): “A similar extrapolation problem would apply if we had used any of the calibrations derived by Casagrande et al. (2006), which were derived for stars with [Fe/H] > −1.9.”
HD 147506b: A Supermassive Planet in an Eccentric Orbit Transiting a Bright Star (2007, methodology): “As a check on Teff , we collected all available photometry for HD 147506 in the Johnson, Cousins, 2MASS, and Tycho systems, and applied a number of color-temperature calibrations (Ramı́rez & Meléndez 2005; Masana et al. 2006; Casagrande et al. 2006) using 7 different color indices.”
ON THE USE OF EMPIRICAL BOLOMETRIC CORRECTIONS FOR STARS (2010, background): “…others) or synthetic spectra based on model atmospheres such as ATLAS9 and MARCS have also been made by many authors, and generally range from −26.74 to −26.77, with minor differences depending on the author even when using the same spectrum (see, e.g., Bessell et al. 1998; Casagrande et al. 2006).”
New constraints on the chemical evolution of the solar neighbourhood and galactic disc(s) - improved astrophysical parameters for the Geneva-Copenhagen Survey (2011, methodology): “…the measured observational errors (σBT , σVT , “j ”, “h ”, “k msigcom” andσ[Fe/H]) was used to estimate the random error in the resultingTeff andFBol(Earth) of each star, to which the systematic uncertainty arising fromthe adopted absolute calibration was added (see Casagrande et al. 2006, 2010).”
Synthetic stellar photometry – I. General considerations and new transformations for broad-band systems (2014, methodology): “In practice, its pole-on and rapidly rotating nature, as well as its suspected variability (although longward of 12µm, Aumann et al. 1984, and thus of no impact on the colours investigated here) complicate things (also see the discussion in Casagrande et al. 2006).”
Oxygen abundances in nearby stars - Clues to the formation and evolution of the Galactic disk (2007, result): “…Santos et al. (2005) have found reasonably good agreement between spectroscopic and direct temperatures for four of their sample stars while Casagrande et al. (2006) have shown that the zero point of the IRFM Teff scale can be in good agreement with the spectroscopic one depending on the…”
M dwarfs: effective temperatures, radii and metallicities (2008, methodology): “We have chosen to use models with no α–enhancement; in any case the use of α–enhanced models in dwarfs of earlier spectral type does not change the results significantly (Casagrande et al. 2006).”
The HARPS search for Earth-like planets in the habitable zone - I. Very low-mass planets around HD 20794, HD 85512, and HD 192310 (2011, methodology): “Indeed, Sousa et al. (2008) derived an effective temperature of 4715 ± 102 K for this star, which disagrees with the value of 4419 K obtained using the IRFM calibration of Casagrande et al. (2006).”