Fundamental parameters of bright Ap stars from wide-range energy distributions and advanced atmospheric models

Abstract

As a well-established procedure for the vast majority of normal main-sequence stars, determination of atmospheric and stellar parameters turns to be a challenging process in case of magnetic chemically peculiar stars. Inhomogeneous distribution of chemical elements and strong magnetic fields make most of the standard photometric and spectroscopic calibrations inapplicable for this class of stars. In this work we make use of available observed energy distributions calibrated to absolute units, stellar parallaxes, high-resolution spectroscopic observations, and advanced stellar atmosphere models to derive parameters of three bright Ap stars: 33Lib, gammaEqu, and betaCrB. Model atmospheres and fluxes were computed with the LLmodels code. Synth3 and Synthmag codes were used to compute profiles of individual spectral lines involved in abundance analysis. For each of the stars, we construct a self-consistent atmospheric models assuming normal and depleted helium compositions and derive empirically stratification profiles of certain elements. The effective temperatures and surface gravities are found from the simultaneous fit to spectroscopic, photometric, and spectrophotometric observations calibrated to absolute units. We show that using advanced model atmospheres and accurate stellar parallaxes allows one to derive stellar radii with high accuracy, and these are consistent with those obtained from independent but more complicated interferometric observations.

accepted by A&A

References in corpus (6)

• Pulsation tomography of rapidly oscillating Ap stars. Resolving the third dimension in peculiar pulsating stellar atmospheres
• Isotopic anomaly and stratification of Ca in magnetic Ap stars
• The fundamental parameters of the roAp star alpha Circini
• Non-LTE line formation for Pr II and Pr III in A and Ap stars
• Heavy Calcium in CP Stars
• Stellar model atmospheres with magnetic line blanketing. III. The role of magnetic field inclination

Cited by in corpus (10)

• Testing excitation models of rapidly oscillating Ap stars with interferometry
• On the consistency of magnetic field measurements of Ap stars: lessons learned from the FORS1 archive
• Fundamental parameters and evolutionary status of the magnetic chemically peculiar stars HD 188041 (V1291 Aquilae), HD 111133 (EP Virginis), and HD 204411. Spectroscopy versus interferometry
• The fundamental parameters of the roAp star 10 Aql
• Fundamental properties of a selected sample of Ap stars: Inferences from interferometric and asteroseismic constraints
• K2 observations of the rapidly oscillating Ap star 33 Lib (HD 137949): new frequencies and unique non-linear interactions
• Pulsation of magnetic stars
• Fundamental parameters of the Ap-stars GO And, 84 UMa, and $\kappa$ Psc
• Discovery and origin of the radio emission from the multiple stellar system KQVel
• HD 34736: An intensely magnetised double-lined spectroscopic binary with rapidly-rotating chemically peculiar B-type components