Details

Autor(en) / Beteiligte

• BURGASSER, Adam J
• CUSHING, Michael C
• MAINZER, A
• THOMPSON, Maggie A
• MARSH, Kenneth A
• BAUER, James M
• WRIGHT, Edward L
• KIRKPATRICK, J. Davy
• GELINO, Christopher R
• GRIFFITH, Roger L
• LOOPER, Dagny L
• TINNEY, Christopher
• SIMCOE, Robert A
• BOCHANSKI, John J
• SKRUTSKIE, Michael F

Titel

FIRE SPECTROSCOPY OF FIVE LATE-TYPE T DWARFS DISCOVERED WITH THE WIDE-FIELD INFRARED SURVEY EXPLORER

Ist Teil von

• The Astrophysical journal, 2011-07, Vol.735 (2), p.jQuery1323906680583='48'-jQuery1323906680583='48'

Ort / Verlag

Bristol: IOP

Erscheinungsjahr

2011

Quelle

EZB Electronic Journals Library

Beschreibungen/Notizen

• We present the discovery of five late-type T dwarfs identified with the Wide-field Infrared Survey Explorer (WISE). Low-resolution near-infrared spectroscopy obtained with the Magellan Folded-port InfraRed Echellette reveal strong H2O and CH4 absorption in all five sources, and spectral indices and comparison to spectral templates indicate classifications ranging from T5.5 to T8.5:. The spectrum of the latest-type source, WISE J1812+2721, is an excellent match to that of the T8.5 companion brown dwarf Wolf 940B. WISE-based spectrophotometric distance estimates place these T dwarfs at 12-13 pc from the Sun, assuming they are single. Preliminary fits of the spectral data to the atmosphere models of Saumon & Marley indicate effective temperatures ranging from 600 K to 930 K, both cloudy and cloud-free atmospheres, and a broad range of ages and masses. In particular, two sources show evidence of both low surface gravity and cloudy atmospheres, tentatively supporting a trend noted in other young brown dwarfs and exoplanets. In contrast, the high proper motion T dwarf WISE J2018--7423 exhibits a suppressed K-band peak and blue spectrophotometric J -- K colors indicative of an old, massive brown dwarf; however, it lacks the broadened Y-band peak seen in metal-poor counterparts. These results illustrate the broad diversity of low-temperature brown dwarfs that will be uncovered with WISE.