Additional Ultracool White Dwarfs Found in the Sloan Digital Sky Survey
| Autor: | V. Malanushenko, H. C. Harris, Mark SubbaRao, Geza Gyuk, Scott F. Anderson, Jeffrey A. Munn, E. Malanushenko, Kaike Pan, Evalyn Gates, Dmitry Bizyaev, Gillian R. Knapp, J. Liebert, Donald P. Schneider, Patrick B. Hall, J. A. Smith |
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| Rok vydání: | 2008 |
| Předmět: |
Physics
media_common.quotation_subject Astrophysics (astro-ph) FOS: Physical sciences Balmer series White dwarf Astronomy and Astrophysics Astrophysics::Cosmology and Extragalactic Astrophysics Astrophysics Spectral line Photometry (optics) Stars symbols.namesake Space and Planetary Science Sky symbols Thick disk Astrophysics::Solar and Stellar Astrophysics Astrophysics::Earth and Planetary Astrophysics Emission spectrum Astrophysics::Galaxy Astrophysics media_common |
| Zdroj: | The Astrophysical Journal. 679:697-703 |
| ISSN: | 1538-4357 0004-637X |
| Popis: | We identify seven new ultracool white dwarfs discovered in the Sloan Digital Sky Survey (SDSS). The SDSS photometry, spectra, and proper motions are presented, and additional BVRI data are given for these and other previously discovered ultracool white dwarfs. The observed colors span a remarkably wide range, qualitatively similar to colors predicted by models for very cool white dwarfs. One of the new stars (SDSS J1251+44) exhibits strong collision-induced absorption (CIA) in its spectra, while the spectra and colors of the other six are consistent with mild CIA. Another of the new discoveries (SDSS J2239+00A) is part of a binary system -- its companion is also a cool white dwarf, and other data indicate that the companion exhibits an infrared flux deficiency, making this the first binary system composed of two CIA white dwarfs. A third discovery (SDSS J0310-00) has weak Balmer emission lines. The proper motions of all seven stars are consistent with membership in the disk or thick disk. Comment: Accepted for Astrophysical Journal. 16 pages (includes 3 figures) |
| Databáze: | OpenAIRE |
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