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  • 标题:Gravity and limb-darkening coefficients for compact stars: DA, DB, and DBA eclipsing white dwarfs ★
  • 本地全文:下载
  • 作者:A. Claret ; E. Cukanovaite ; K. Burdge
  • 期刊名称:Astronomy & Astrophysics
  • 印刷版ISSN:0004-6361
  • 电子版ISSN:1432-0746
  • 出版年度:2020
  • 卷号:634
  • 页码:1-9
  • DOI:10.1051/0004-6361/201937326
  • 语种:English
  • 出版社:EDP Sciences
  • 摘要: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, andGaiaphotometric 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 coefficientsy(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 (∂lnIo(λ)/∂lng)Teff.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 loggvarying 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], logg, andTeffcan be performed upon request.
  • 关键词:Key wordsenbinaries: eclipsingwhite dwarfsstars: evolutionplanetary systems
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