A Spectroscopic Study of Cool, Field Brown Dwarf Neighbors
نویسندگان
چکیده
The Sloan Digital Sky Survey (SDSS), Two Micron Sky Survey (2MASS) and Deep Near Infrared Survey (DENIS) have already found many dozens of brown dwarfs in the late 1990s. Many of the new spectral class of L dwarfs show undepleted lithium, which indicates that their deep interiors are not hot enough to fuse protons. Methane or T dwarfs with surface temperatures near 1,000 K have also been found as isolated objects in the solar neighborhood. The predicted luminosity function of substellar objects peaks at still lower temperatures (∼400-500 K) where MK is fainter than 20th, and the above-mentioned surveys are not sensitive. These objects are expected to emit significant radiation in the 3.5– 10μ wavelength range. Spectrophotometric study of these faint entities can be conducted only with the NGST. Study of the atmospheric abundances and line profiles is essential to determine such things as the surface temperature and gravity (mass), rotation rate, amount of dust and cloud formation, mixing and other important atmospheric processes. One also wants to know if they form disks and planets, and exhibit magnetic dynamo activity. The astrophysics of field substellar objects is a new piece of the overall study of planet and star formation processes. ASWG DRM Proposal A Spectroscopic Study of Cool, Field Brown Dwarf Neighbors Observing Summary: Target RA Dec mAB Configuration/mode Days .13 GL 229B 05 08 28 -21 50 36 K=14.3 N&MIRSPEC R10000 0 .13 2MASSW J1632 16 32 29 +19 04 41 K=13.98 N&MIRSPEC R10000 0 .13 DENIS-P J1228 12 28 12 -15 47 00 K=12.81 N&MIRSPEC R10000 0 .14 J162414 16 24 14 00 00 00 K=17.6 N&MIRSPEC R10000 0 .21 J1217 12 17 11 -03 11 13 K=18.3 N&MIRSPEC R10000 0 .14 J1225 12 25 54 -27 39 47 K=16.9 N&MIRSPEC R10000 0 .18 J1237 12 37 39 +65 26 15 K=18. N&MIRSPEC R10000 0 .18 J1346 13 46 46 -00 31 50 K=18 N&MIRSPEC R10000 0 .0 COOLER TDS 9-11 180 00 00 +65 K=21 N&MIRSPEC R10000 12 Grand total days 12 NOTE: This grand total (12) does not equal the number (0) given on page 1
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