论文标题
氦气白色矮人的3D光谱分析
3D spectroscopic analysis of helium-line white dwarfs
论文作者
论文摘要
在本文中，我们对DB和DBA白色矮人的光谱参数进行了更正，其基于282 3D大气模型，该模型使用CO5BOLD RADIADIAD -HYDRODYNARGYNAMICS计算出282 3D大气模型。与先前可用的1D模型大气相比，这些校正是由于对3D模型中对流能量传输的更好物理处理而产生的。通过将校正施加到现有的DB和DBA白色矮人的SDSS样本中，我们发现有效温度和表面重力的校正都有明显的校正。对于T_EFF <18000 K，3D log（g）校正最为重要，在log（g）= 8.0处达到-0.20 dex。但是，在这个低有效的温度范围内，由光谱技术确定的表面重力也可能受到中性范德华线的处理氦气宽扩大和由于中性原子扰动氦气而导致的非理想效应。因此，通过消除由于一维对流而导致的不确定性，我们的工作表明了对DB和DBA模型大气的微物理学描述的需求。总体而言，我们发现SDSS样品的3D光谱参数通常与单个白色矮人1-3σ之内的Gaia DR2绝对通量一致。通过将我们的结果与DA白矮人进行比较，我们确定了DB/DBA大气模型的精度和准确性相似。为了易于校正功能的用户应用，我们提供了一个示例Python代码。
In this paper, we present corrections to the spectroscopic parameters of DB and DBA white dwarfs with -10.0 < log(H/He) < -2.0, 7.5 < log(g) < 9.0 and 12000 K < T_eff < 34000 K, based on 282 3D atmospheric models calculated with the CO5BOLD radiation-hydrodynamics code. These corrections arise due to a better physical treatment of convective energy transport in 3D models when compared to the previously available 1D model atmospheres. By applying the corrections to an existing SDSS sample of DB and DBA white dwarfs, we find significant corrections both for the effective temperature and surface gravity. The 3D log(g) corrections are most significant for T_eff < 18000 K, reaching up to -0.20 dex at log(g) = 8.0. However, in this low effective temperature range, the surface gravity determined from the spectroscopic technique can also be significantly affected by the treatment of the neutral van der Waals line broadening of helium and by non-ideal effects due to the perturbation of helium by neutral atoms. Thus, by removing uncertainties due to 1D convection, our work showcases the need for improved description of microphysics for DB and DBA model atmospheres. Overall, we find that our 3D spectroscopic parameters for the SDSS sample are generally in agreement with Gaia DR2 absolute fluxes within 1-3σ for individual white dwarfs. By comparing our results to DA white dwarfs, we have determined that the precision and accuracy of DB/DBA atmospheric models are similar. For ease of user application of the correction functions, we provide an example Python code.
