Binarity at the L/T brown dwarf transition
| العنوان: | Binarity at the L/T brown dwarf transition |
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| المؤلفون: | Bertrand Goldman, Wolfgang Brandner, M. B. Stumpf, M. R. Zapatero Osorio, Th. Henning, Hervé Bouy |
| المصدر: | Astronomy & Astrophysics. 490:763-768 |
| بيانات النشر: | EDP Sciences, 2008. |
| سنة النشر: | 2008 |
| مصطلحات موضوعية: | Physics, Laser guide star, Space and Planetary Science, Brown dwarf, Astronomy and Astrophysics, Astrophysics, Adaptive optics systems |
| الوصف: | Current atmospheric models cannot reproduce some of the characteristics of the transition between the L dwarfs with cloudy atmospheres and the T dwarfs with dust-depleted photospheres. It has been proposed that a majority of the L/T transition brown dwarfs could actually be a combinaison of a cloudy L dwarf and a clear T dwarf. Indeed binarity seems to occur more frequently among L/T transition brown dwarfs. We aim to refine the statistical significance of the seemingly higher frequency of binaries. Co-eval binaries would also be interesting test-beds for evolutionary models. We obtained high-resolution imaging for six mid-L to late-T dwarfs, with photometric distances between 8 and 33pc, using the adaptive optics systems NACO at the VLT, and the Lick system, both with the laser guide star. We resolve none of our targets. Combining our data with published results, we obtain a frequency of resolved L/T transition brown dwarfs of (31+21-15)%, compared to (21+10-7)% and (14+14-7)% for mid-L and T dwarfs (90% of confidence level). These fractions do not significantly support, nor contradict, the hypothesis of a larger binary fraction in the L/T transition. None of our targets has companions with effective temperatures as low as 360-1000K at separations larger than 0.5". |
| تدمد: | 1432-0746 0004-6361 |
| DOI: | 10.1051/0004-6361:200810605 |
| URL الوصول: | https://explore.openaire.eu/search/publication?articleId=doi_________::2b173380d10110a5584f13eb410f9c7b https://doi.org/10.1051/0004-6361:200810605 |
| Rights: | OPEN |
| رقم الانضمام: | edsair.doi...........2b173380d10110a5584f13eb410f9c7b |
| قاعدة البيانات: | OpenAIRE |
| تدمد: | 14320746 00046361 |
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| DOI: | 10.1051/0004-6361:200810605 |