Astronomy and Astrophysics, volume 640A, 2-2 (2020/8-1)
Precise calibration of the dependence of surface brightness-colour relations on colour and class for late-type stars.
SALSI A., NARDETTO N., MOURARD D., CREEVEY O., HUBER D., WHITE T.R., HOCDE V., MORAND F., TALLON-BOSC I., FARRINGTON C.D., CHELLI A. and DUVERT G.
Abstract (from CDS):
Context. Surface brightness-colour relations (SBCRs) are used to derive the stellar angular diameters from photometric observations. They have various astrophysical applications, such as the distance determination of eclipsing binaries or the determination of exoplanet parameters. However, strong discrepancies between the SBCRs still exist in the literature, in particular for early and late-type stars.
Aims. We aim to calibrate new SBCRs as a function of the spectral type and the luminosity class of the stars. Our goal is also to apply homogeneous criteria to the selection of the reference stars and in view of compiling an exhaustive and up-to-date list of interferometric late-type targets.
Methods. We implemented criteria to select measurements in the JMMC Measured Diameters Catalog. We then applied additional criteria on the photometric measurements used to build the SBCRs, together with stellar characteristics diagnostics.
Results. We built SBCRs for F5/K7-II/III, F5/K7-IV/V, M-II/III and M-V stars, with respective rms of σFV=0.0022mag, σFV=0.0044mag, σFV=0.0046mag, and σFV=0.0038mag. This results in a precision on the angular diameter of 1.0%, 2.0%, 2.1%, and 1.7%, respectively. These relations cover a large V-K colour range of magnitude, from 1 to 7.5. Our work demonstrates that SBCRs are significantly dependent on the spectral type and the luminosity class of the star. Through a new set of interferometric measurements, we demonstrate the critical importance of the selection criteria proposed for the calibration of SBCR. Finally, using the Gaia photometry for our samples, we obtained (G-K) SBCRs with a precision on the angular diameter between 1.1% and 2.4%.
Conclusions. By adopting a refined and homogeneous methodology, we show that the spectral type and the class of the star should be considered when applying an SBCR. This is particularly important in the context of PLATO.
© A. Salsi et al. 2020
techniques: interferometric - stars: atmospheres - stars: late-type - stars: fundamental parameters
VizieR on-line data:
<Available at CDS (J/A+A/640/A2): dwarfs.dat giants.dat m_dwarfs.dat m_giants.dat>
erratum vol. 641, art. C3 (2020)
View the references in ADS
To bookmark this query, right click on this link: simbad:2020A&A...640A...2S and select 'bookmark this link' or equivalent in the popup menu