THE PROPERTIES OF THE 500 K DWARF UGPS J072227.51-054031.2 AND A STUDY OF THE FAR-RED FLUX OF COLD BROWN DWARFS

Journal Article · Sun Apr 01 00:00:00 EDT 2012 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/748/2/74· OSTI ID:22016136

Leggett, S K ^[1]; Saumon, D ^[2]; Marley, M S ^[3]; Lodders, K; Fegley, B ^[4]; Canty, J; Lucas, P; Burningham, Ben; Jones, H R. A.; Marocco, F; Pinfield, D J ^[5]; Smart, R L ^[6]; Tinney, C G ^[7]; Homeier, D; Allard, F ^[8]; Day-Jones, A ^[9]; Ishii, Miki ^[10]; Tamura, M ^[11]

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1. Gemini Observatory, Northern Operations Center, 670 N. A'ohoku Place, Hilo, HI 96720 (United States)
2. Los Alamos National Laboratory, P.O. Box 1663, MS F663, Los Alamos, NM 87545 (United States)
3. NASA Ames Research Center, Mail Stop 245-3, Moffett Field, CA 94035 (United States)
4. Planetary Chemistry Laboratory, Department of Earth and Planetary Sciences, McDonnell Center for the Space Sciences, Washington University, St. Louis, MO 63130-4899 (United States)
5. Centre for Astrophysics Research, Science and Technology Research Institute, University of Hertfordshire, Hatfield AL10 9AB (United Kingdom)
6. INAF/Osservatorio Astronomico di Torino, Strada Osservatorio 20, 10025 Pino Torinese (Italy)
7. Department of Astrophysics, University of New South Wales, NSW 2052 (Australia)
8. CRAL, Universite de Lyon, Ecole Normale Superieur, 46 allee d'Italie, 69364 Lyon Cedex 07 (France)
9. Universidad de Chile, Camino el Observatorio No. 1515, Santiago, Casilla 36-D (Chile)
10. Subaru Telescope, National Astronomical Observatory of Japan, 650 N. A'ohoku Place, Hilo, HI 96720 (United States)
11. National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan)

We present i and z photometry for 25 T dwarfs and 1 L dwarf. Combined with published photometry, the data show that the i - z, z - Y, and z - J colors of T dwarfs are very red, and continue to increase through to the late-type T dwarfs, with a hint of a saturation for the latest types with T{sub eff} Almost-Equal-To 600 K. We present new 0.7-1.0 {mu}m and 2.8-4.2 {mu}m spectra for the very late type T dwarf UGPS J072227.51-054031.2, as well as improved astrometry for this dwarf. Examination of the spectral energy distribution using new and published data, with Saumon and Marley models, shows that the dwarf has T{sub eff} = 505 {+-} 10 K, a mass of 3-11 M{sub Jupiter}, and an age between 60 Myr and 1 Gyr. This young age is consistent with the thin disk kinematics of the dwarf. The mass range overlaps with that usually considered to be planetary, despite this being an unbound object discovered in the field near the Sun. This apparently young rapid rotator is also undergoing vigorous atmospheric mixing, as determined by the IRAC and WISE 4.5 {mu}m photometry and the Saumon and Marley models. The optical spectrum for this 500 K object shows clearly detected lines of the neutral alkalis Cs and Rb, which are emitted from deep atmospheric layers with temperatures of 900-1200 K.

• OSTI ID: 22016136
• Journal Information: Astrophysical Journal, Vol. 748, Issue 2; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTROPHYSICS
COSMOLOGY AND ASTRONOMY
ABUNDANCE
ENERGY SPECTRA
MASS
PHOTOMETRY
SUN