Bibliographic Details
| Title: |
The 100 pc White Dwarf Sample in the SDSS Footprint II. A New Look at the Spectral Evolution of White Dwarfs |
| Authors: |
Kilic, Mukremin, Bergeron, Pierre, Blouin, Simon, Moss, Adam, Brown, Warren R., Bedard, Antoine, Jewett, Gracyn, Agueros, Marcel A. |
| Publication Year: |
2024 |
| Collection: |
Astrophysics |
| Subject Terms: |
Astrophysics - Solar and Stellar Astrophysics |
| More Details: |
We increase the spectroscopic completeness of the 100 pc white dwarf sample in the SDSS footprint with 840 additional spectra. Our spectroscopy is 86% complete for white dwarfs hotter than $T_{\rm eff}= 5000$ K, where H$\alpha$ remains visible and provides reliable constraints on the atmospheric composition. We identify 2108 DA white dwarfs with pure hydrogen atmospheres, and show that ultramassive DA white dwarfs with $M\geq1.1~M_{\odot}$ are an order of magnitude less common below 10,000 K. This is consistent with a fraction of them getting stuck on the crystallization sequence due to $^{22}$Ne distillation. In addition, there are no ultramassive DA white dwarfs with $M\geq1.1~M_{\odot}$ and $T_{\rm eff}\leq6000$ K in our sample, likely because Debye cooling makes them rapidly fade away. We detect a significant trend in the fraction of He-atmosphere white dwarfs as a function of temperature; the fraction increases from 9% at 20,000 K to 32% at 6000 K. This provides direct evidence of convective mixing in cool DA white dwarfs. Finally, we detect a relatively tight sequence of low-mass DQ white dwarfs in color-magnitude diagrams for the first time. We discuss the implications of this tight DQ sequence, and conclude with a discussion of the future prospects from the upcoming ULTRASAT mission and the large-scale multi-fiber spectroscopic surveys.
Comment: ApJ, in press |
| Document Type: |
Working Paper |
| Access URL: |
http://arxiv.org/abs/2412.04611 |
| Accession Number: |
edsarx.2412.04611 |
| Database: |
arXiv |
