3D Model Atmospheres for Extremely Low-Mass White Dwarfs
2015 (English)In: Astrophysical Journal, ISSN 0004-637X, E-ISSN 1538-4357, Vol. 809, no 2, 148Article in journal (Refereed) Published
We present an extended grid of mean three-dimensional (3D) spectra for low-mass, pure-hydrogen atmosphere DA white dwarfs (WDs). We use CO5BOLD radiation-hydrodynamics 3D simulations covering T-eff = 6000-11,500 K and log g = 5-6.5 (g in cm s(-2)) to derive analytical functions to convert spectroscopically determined 1D temperatures and surface gravities to 3D atmospheric parameters. Along with the previously published 3D models, the 1D to 3D corrections are now available for essentially all known convective DA WDs (i.e., log g - 5-9). For low-mass WDs, the correction in temperature is relatively small (a few percent at the most), but the surface gravities measured from the 3D models are lower by as much as 0.35 dex. We revisit the spectroscopic analysis of the extremely low-mass (ELM) WDs, and demonstrate that the 3D models largely resolve the discrepancies seen in the radius and mass measurements for relatively cool ELM WDs in eclipsing double WD and WD + millisecond pulsar binary systems. We also use the 3D corrections to revise the boundaries of the ZZ Ceti instability strip, including the recently found ELM pulsators.
Place, publisher, year, edition, pages
2015. Vol. 809, no 2, 148
convection, hydrodynamics, white dwarfs
Astronomy, Astrophysics and Cosmology
IdentifiersURN: urn:nbn:se:uu:diva-265630DOI: 10.1088/0004-637X/809/2/148ISI: 000361655100041OAI: oai:DiVA.org:uu-265630DiVA: diva2:866976