相关论文: Gravity and limb-darkening coefficients for compac…

We perform a calibration of the mixing length parameter at the bottom boundary of the convection zone for helium-dominated atmospheres of white dwarfs. This calibration is based on a grid of 3D DB (pure-helium) and DBA (helium-dominated…

We present a detailed spectroscopic and photometric analysis of DA and DB white dwarfs drawn from the Sloan Digital Sky Survey with trigonometric parallax measurements available from the Gaia mission. The temperature and mass scales…

The atmospheres of very cool, hydrogen-rich white dwarfs (Teff <6000 K) are challenging to models because of the increased complexity of the equation of state, chemical equilibrium, and opacity sources in a low-temperature, weakly ionized…

Thanks to their continuous cooling and relative simplicity, white dwarf stars are routinely used to measure the ages of stellar populations. The usefulness of white dwarfs as cosmochronometers depends on the availability of accurate cooling…

We consider the problem of radiative transfer in stellar atmospheres where the index of refraction departs from unity and is a function of density and temperature. We present modified Feautrier and Lambda-iteration methods to solve the…

We present a detailed spectroscopic analysis of 115 helium-line (DB) and 28 cool, He-rich hydrogen-line (DA) white dwarfs based on atmosphere fits to optical spectroscopy and photometry. We find that 63% of our DB population show hydrogen…

Observation of the strengths and profiles of the hydrogen Balmer absorption series is an established technique for determining the effective temperature and surface gravity of hot H-rich white dwarf stars. In principle, the Lyman series…

Limb-darkening is a fundamental constraint for modeling eclipsing binary and planetary transit light curves. As observations, for example from Kepler, CoRot, and Most, become more precise then a greater understanding of limb-darkening is…

We compute the emergent stellar spectra from the UV to far infrared for different viewing angles using realistic 3D model atmospheres for a large range in stellar parameters to predict the stellar limb darkening. We have computed full 3D…

We measure apparent velocities (v_app) of absorption lines for 36 white dwarfs (WDs) with helium-dominated atmospheres -- 16 DBAs and 20 DBs -- using optical spectra taken for the European Southern Observatory SN Ia progenitor survey (SPY).…

Characterization of the atmospheres of transiting exoplanets relies on accurate measurements of the extent of the optically thick area of the planet at multiple wavelengths with a precision $\lesssim$100 parts per million (ppm).…

White dwarfs with metal-polluted atmospheres have been studied widely in the context of the accretion of rocky debris from evolved planetary systems. One open question is the geometry of accretion and how material arrives and mixes in the…

We provide here tables of stellar limb-darkening coefficients (LDCs) for the Ariel ESA M4 space mission. These tables include LDCs corresponding to different wavelength bins and white bands for the NIRSpec, AIRS-Ch0 and AIRS-Ch1…

We present the first grid of mean three-dimensional (3D) spectra for pure-hydrogen (DA) white dwarfs based on 3D model atmospheres. We use CO5BOLD radiation-hydrodynamics 3D simulations instead of the mixing-length theory for the treatment…

We present a detailed analysis of 108 helium-line (DB) white dwarfs based on model atmosphere fits to high signal-to-noise optical spectroscopy. We derive a mean mass of 0.67 Mo for our sample, with a dispersion of only 0.09 Mo. White…

Traces of photospheric hydrogen are detected in at least half of all white dwarfs with helium-dominated atmospheres through the presence of H alpha in high-quality optical spectroscopy. Previous studies have noted significant discrepancies…

A sequence of pure-hydrogen CO5BOLD 3D model atmospheres of DA white dwarfs is presented for a surface gravity of log g = 8 and effective temperatures from 6000 to 13,000 K. We show that convective properties, such as flow velocities,…

Observations of galactic white dwarfs with Gaia have allowed for unprecedented modeling of white dwarf cooling, resolving core crystallization and sedimentary heating from neutron rich nuclei. These cooling sequences are sensitive to the…

We compare limb darkening laws derived from 3D hydrodynamical model atmospheres and 1D hydrostatic MARCS models for the host stars of the two transiting exoplanet systems HD 209458 and HD 189733. The surface brightness distribution of the…

For the nearby dwarf star alpha Cen B (K1 V), we present limb darkening predictions from a 3D hydro-dynamical radiative transfer model of its atmosphere. We first compare the results of this model to a standard Kurucz's atmosphere. Then we…