论文标题
对盖亚和泛星际脚印的凉爽白矮人的光谱分析
A Spectro-photometric Analysis of Cool White Dwarfs in the Gaia and Pan-STARRS Footprint
论文作者
论文摘要
我们提供了比太阳100 pc之内的2880个冷的白色矮人的光谱分析，比teff = 10,000 k的光谱分析，带有Grizy Pan-Starrs光度法和Gaia Trighonometricral-Parallaxes。我们还为数据集补充了近红外JHK光度法，如果可用，这对于解释样品中最酷的白矮人至关重要。我们使用适合每种光谱类型的最新模型大气对每个对象进行详细分析，包括DA，DC，DQ，DZ，HE-HE-HE-HE-HE-HE-HE-HE-HE-HE-HE-HE-FARTIAL IR-IRPAIRT WHALFS。我们讨论了每个子样本的温度和质量分布，并重新审视冷白矮人的光谱演化。我们在样本中几乎没有证据表明，通过对流混合的过程在Teff = 10,000 K和6500 K之间转化了大量的DA恒星向He-Aposphere白色矮人，尽管这种情况在TEFF = 6500-5500 K范围内发生了巨大变化，而He-Atmosphere WhiteMosphere White Dwarfs的一部分则属于45％。但是，我们还提供了有力的证据表明，在凉爽的温度（TEFF <5200 K）下，大多数DC白色矮人都有H大气。我们讨论了一种可能说明从He-h-atmosphere的突然转化的可能机制，涉及结晶的发作和磁性的发生。最后，我们还认为DQ，DZ和DC白矮人可能形成比以前认为的更均匀的人群。
We present a spectro-photometric analysis of 2880 cool white dwarfs within 100 pc of the Sun and cooler than Teff = 10,000 K, with grizy Pan-STARRS photometry and Gaia trigonometric parallaxes available. We also supplement our data sets with near-infrared JHK photometry, when available, which is shown to be essential for interpreting the coolest white dwarfs in our sample. We perform a detailed analysis of each individual object using state-of-the-art model atmospheres appropriate for each spectral type including DA, DC, DQ, DZ, He-rich DA, and the so-called IR-faint white dwarfs. We discuss the temperature and mass distributions of each subsample, as well as revisit the spectral evolution of cool white dwarfs. We find little evidence in our sample for the transformation of a significant fraction of DA stars into He-atmosphere white dwarfs through the process of convective mixing between Teff = 10,000 K and 6500 K, although the situation changes drastically in the range Teff = 6500 - 5500 K where the fraction of He-atmosphere white dwarfs reaches 45%. However, we also provide strong evidence that at even cooler temperatures (Teff < 5200 K), most DC white dwarfs have H atmospheres. We discuss a possible mechanism to account for this sudden transformation from He- to H-atmosphere white dwarfs involving the onset of crystallization and the occurrence of magnetism. Finally, we also argue that DQ, DZ, and DC white dwarfs may form a more homogeneous population than previously believed.
