Precise calibration of the dependence of surface brightness-colour relations on colour and class for late-type stars
ASTRONOMY & ASTROPHYSICS
Authors: 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.; Duvert, G.
Abstract
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 sigma(FV) = 0.0022 mag, sigma(FV) = 0.0044 mag, sigma(FV) = 0.0046 mag, and sigma(FV) = 0.0038 mag. 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.
Quantitative LC-MS proteoform profiling of intact wheat glutenin subunits
JOURNAL OF CEREAL SCIENCE
Authors: Bacala, Ray; Fu, Bin Xiao; Perreault, Helene; Hatcher, Dave W.
Abstract
Methodology for the quantitative analysis of intact glutenin proteins by ESI-LC-MS was developed with 1 Da mass resolution, constituting the first published application of proteoform profiling to plant biology. Two parent lines and 28 F5 crosses were analyzed in two blocks, 14 months apart. Control sample data were used to align retention times and normalize abundance between sample sets. A total of 4622 observations of 347 distinct proteoforms between 17 899 and 88 744 Da were observed. Proteoform abundances spanned a 1000-fold range and were linear (r(2) > 0.990) with dilution. A novel method for the objective elimination of low intensity, noise-dominated data using replicate variability within the dataset is presented. Two abundant PTMs were detected; one known but uncharacterized Bx and Dy high-molecular-weight glutenin subunit (HMWGS) PTM and the other in 24 low molecular weight proteoform pairs. Finally, 16 abundant proteoforms were detected in progeny but not in either parent. This application should increase the statistical power of correlations between gluten complement and functional data and drive the detection of novel PTMs that may indicate differential regulation of the cellular processes related to quality.