تقرير
The brightest pure-H ultracool white dwarf
| العنوان: | The brightest pure-H ultracool white dwarf |
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| المؤلفون: | Catalan, S., Tremblay, P. -E., Pinfield, D. J., Smith, L. C., Zhang, Z. H., Napiwotzki, R., Marocco, F., Day-Jones, A. C., Gomes, J., Forde, K. P., Lucas, P. W., Jones, H. R. A. |
| سنة النشر: | 2012 |
| المجموعة: | Astrophysics |
| مصطلحات موضوعية: | Astrophysics - Solar and Stellar Astrophysics |
| الوصف: | We report the identification of LSR J0745+2627 in the United Kingdom InfraRed Telescope Infrared Deep Sky Survey (UKIDSS) Large Area Survey (LAS) as a cool white dwarf with kinematics and age compatible with the thick-disk/halo population. LSR J0745+2627 has a high proper motion (890 mas/yr) and a high reduced proper motion value in the J band (H_J=21.87). We show how the infrared-reduced proper motion diagram is useful for selecting a sample of cool white dwarfs with low contamination. LSR J0745+2627 is also detected in the Sloan Digital Sky Survey (SDSS) and the Wide-field Infrared Survey Explorer (WISE). We have spectroscopically confirmed this object as a cool white dwarf using X-Shooter on the Very Large Telescope. A detailed analysis of its spectral energy distribution reveals that its atmosphere is compatible with a pure-H composition model with an effective temperature of 3880+-90 K. This object is the brightest pure-H ultracool white dwarf (Teff<4000 K) ever identified. We have constrained the distance (24-45 pc), space velocities and age considering different surface gravities. The results obtained suggest that LSR J0745+2627 belongs to the thick-disk/halo population and is also one of the closest ultracool white dwarfs. Comment: 5 pages, 7 figures, accepted for publication in A&A Letters |
| نوع الوثيقة: | Working Paper |
| DOI: | 10.1051/0004-6361/201220191 |
| URL الوصول: | http://arxiv.org/abs/1209.1403 |
| رقم الأكسشن: | edsarx.1209.1403 |
| قاعدة البيانات: | arXiv |
| DOI: | 10.1051/0004-6361/201220191 |
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