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Gravity and limb-darkening coefficients for compact stars: DA, DB, and DBA eclipsing white dwarfs

Claret, A. and Cukanovaite, E. and Burdge, K. and Tremblay, P.-E. and Parsons, S. and Marsh, T. R. (2020) Gravity and limb-darkening coefficients for compact stars: DA, DB, and DBA eclipsing white dwarfs. Astronomy and Astrophysics, 634 . Art. No. A93. ISSN 0004-6361. https://resolver.caltech.edu/CaltechAUTHORS:20200309-083101170

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Abstract

Context. The distribution of the specific intensity over the stellar disk is an essential tool for modeling the light curves in eclipsing binaries, planetary transits, and stellar diameters through interferometric techniques, line profiles in rotating stars, gravitational microlensing, etc. However, the available theoretical calculations are mostly restricted to stars on the main sequence or the giant branch, and very few calculations are available for compact stars. Aims. The main objective of the present work is to extend these investigations by computing the gravity and limb-darkening coefficients for white dwarf atmosphere models with hydrogen, helium, or mixed compositions (types DA, DB, and DBA). Methods. We computed gravity and limb-darkening coefficients for DA, DB, and DBA white dwarfs atmosphere models, covering the transmission curves of the Sloan, UBVRI, Kepler, TESS, and Gaia photometric systems. Specific calculations for the HiPERCAM instrument were also carried out. For all calculations of the limb-darkening coefficients we used the least-squares method. Concerning the effects of tidal and rotational distortions, we also computed for the first time the gravity-darkening coefficients y(λ) for white dwarfs using the same models of stellar atmospheres as in the case of limb-darkening. A more general differential equation was introduced to derive these quantities, including the partial derivative (∂ln Io(λ)/∂ln g)T_(eff). Results. Six laws were adopted to describe the specific intensity distribution: linear, quadratic, square root, logarithmic, power-2, and a more general one with four coefficients. The computations are presented for the chemical compositions log[H/He] = −10.0 (DB), −2.0 (DBA) and He/H = 0 (DA), with log g varying between 5.0 and 9.5 and effective temperatures between 3750 and 100 000 K. For effective temperatures higher than 40 000 K, the models were also computed adopting nonlocal thermal equilibirum (DA). The adopted mixing-length parameters are ML2/α = 0.8 (DA case) and 1.25 (DB and DBA). The results are presented in the form of 112 tables. Additional calculations, such as for other photometric systems and/or different values of log[H/He], log g, and T_(eff) can be performed upon request.


Item Type:Article
Related URLs:
URLURL TypeDescription
https://doi.org/10.1051/0004-6361/201937326DOIArticle
https://arxiv.org/abs/2001.07129arXivDiscussion Paper
ORCID:
AuthorORCID
Burdge, K.0000-0002-7226-836X
Marsh, T. R.0000-0002-2498-7589
Additional Information:© 2020 ESO. Article published by EDP Sciences. Received 16 December 2019; Accepted 15 January 2020; Published online 14 February 2020. We thank the anonymous referee for helpful comments that have improved the manuscript. The Spanish MEC (AYA2015-71718-R and ESP2017-87676-C5-2-R) is gratefully acknowledged for its support during the development of this work. A.C. also acknowledges financial support from the State Agency for Research of the Spanish MCIU through the “Center of Excellence Severo Ochoa” award for the Instituto de Astrofísica de Andalucía (SEV-2017-0709). The research leading to these results has received funding from the European Research Council under the European Union’s Horizon 2020 research and innovation programme n. 677706 (WD3D). This research has made use of the SIMBAD database, operated at the CDS, Strasbourg, France, and of NASA’s Astrophysics Data System Abstract Service.
Funders:
Funding AgencyGrant Number
Ministerio de Ciencia e Innovación (MCINN)AYA2015-71718-R
Ministerio de Ciencia e Innovación (MCINN)ESP2017-87676-C5-2-R
Severo OchoaSEV-2017-0709
European Research Council (ERC)677706
Subject Keywords:binaries: eclipsing – white dwarfs – stars: evolution – planetary systems
Record Number:CaltechAUTHORS:20200309-083101170
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20200309-083101170
Official Citation:Gravity and limb-darkening coefficients for compact stars: DA, DB, and DBA eclipsing white dwarfs. A. Claret, E. Cukanovaite, K. Burdge, P.-E. Tremblay, S. Parsons and T. R. Marsh. A&A, 634 (2020) A93; DOI: https://doi.org/10.1051/0004-6361/201937326
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:101765
Collection:CaltechAUTHORS
Deposited By: Tony Diaz
Deposited On:09 Mar 2020 17:07
Last Modified:09 Mar 2020 17:07

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