Stephens, D. C., Leggett, S. K., Cushing, Michael C., Marley, Mark S., Saumon, D., Geballe, T. R., ...
We present new 5.2-14.5 micron low-resolution spectra of 14 mid-L to mid-T dwarfs, as well as 3.0-4.1 micron spectra for five of these dwarfs. These data are supplemented by existing red and...
The Physical Properties of Four ~600 K T Dwarfs (2009)
Leggett, S. K., Cushing, Michael C., Saumon, D., Marley, M. S., Roellig, T. L., Warren, S. J., ...
We present Spitzer 7.6-14.5 μm spectra of ULAS J003402.77–005206.7 and ULAS J133553.45+113005.2, two T9 dwarfs with the latest spectral types currently known. We fit synthetic spectra and...
Fortney, J. J., Glenzer, S. H., Koenig, M., Militzer, B., Saumon, D., Valencia, D.
Recent developments of dynamic x-ray characterization experiments of dense matter are reviewed, with particular emphasis on conditions relevant to interiors of terrestrial and gas giant planets....
The Physical Properties of Four ~600K T Dwarfs (2009)
Leggett, S. K., Cushing, M. C., Saumon, D., Marley, M. S., Roellig, T. L., Warren, S. J., ...
We present Spitzer 7.6-14.5um spectra of ULAS J003402.77-005206.7 and ULAS J133553.45+113005.2, two T9 dwarfs with the latest spectral types currently known. We fit synthetic spectra and photometry...
Spectroscopic Detection of Carbon Monoxide in Two Late-type T Dwarfs (2009)
Geballe, T. R., Saumon, D., Golimowski, D. A., Leggett, S. K., Marley, M. S., Noll, K. S.
M band spectra of two late-type T dwarfs, 2MASS J09373487+2931409, and Gliese 570D, confirm evidence from photometry that photospheric CO is present at abundance levels far in excess of those...
The physical properties of four ~600 K T dwarfs. (2009)
Leggett, S., Cushing, M.C., Saumon, D., Marley, M., Roellig, T.L., Warren, S.J., ...
Original article can be found at: http://www.iop.org/EJ/journal/apj Copyright American Astronomical Society DOI: 10.1088/0004-637X/695/2/1517 [Full text of this article is not available in the UHRA]
Moderate-resolution Spitzer infrared spectrograph observations of M, L, and T dwarfs (2008)
Mainzer, A. K., Roellig, Thomas L., Saumon, D., Marley, Mark S., Cushing, Michael C., Sloan, G. C., ...
We present 10-19 μm moderate-resolution spectra of 10 M dwarfs, one L dwarf, and two T dwarf systems obtained with the Infrared Spectrograph (IRS) on board the Spitzer Space Telescope. The IRS...
The Evolution of L and T Dwarfs in Color-Magnitude Diagrams (2008)
We present new evolution sequences for very low mass stars, brown dwarfs and giant planets and use them to explore a variety of influences on the evolution of these objects. We compare our results...
HN Peg B: A Test of Models of the L to T Dwarf Transition (2008)
Leggett, S. K., Saumon, D., Albert, Loic, Cushing, Michael C., Liu, Michael C., Luhman, K. L., ...
Luhman and collaborators recently discovered an early-T dwarf companion to the G0 dwarf star HN Peg, using Spitzer Infrared Array Camera (IRAC) images. Companionship was established on the basis of...
HN Peg B: A Test of Models of the L to T Dwarf Transition (2008)
Leggett, S. K., Saumon, D., Albert, Loic, Cushing, Michael. C., Liu, Michael C., Luhman, K. L., ...
Luhman and collaborators recently discovered an early-T dwarf companion to the G0 dwarf star HN Peg, using Spitzer Infrared Array Camera (IRAC) images. Companionship was established on the basis of...
Properties of the Coolest Dwarfs. (2008)
Leggett, S., Freedman, R., Geballe, T., Golimowski, D., Lodieu, N., Marley, M., ...
B. R. Oppenheimer, D. Saumon, S. T. Hodgkin, R. F. Jameson, N. C. Hambly, G. Chabrier, ...
We present new spectroscopic and photometric measurements of the white dwarfs LHS 3250 and WD 0346]246. Along with F351[50, these white dwarfs are the coolest ones known, all with e+ective...
Atmospheric Parameters of Field L and T Dwarfs (2007)
Cushing, Michael C., Marley, Mark S., Saumon, D., Kelly, Brandon C., Vacca, William D., Rayner, John T., ...
We present an analysis of the 0.95-14.5 micron spectral energy distributions of nine field ultracool dwarfs with spectral types ranging from L1 to T4.5. Effective temperatures, gravities, and...
Physical and Spectral Characteristics of the T8 and Later-Type Dwarfs (2007)
Leggett, S. K., Marley, M. S., Freedman, R., Saumon, D., Liu, Michael C., Geballe, T. R., ...
We use new and published near-IR spectra, with synthetic spectra, to derive physical properties of three of the latest-type T dwarfs. A new R~1700 spectrum of the T7.5 dwarf HD 3651B, with existing...
Moderate Resolution Spitzer Infrared Spectrograph (IRS) Observations of M, L, and T Dwarfs (2007)
Mainzer, A. K., Roellig, Thomas L., Saumon, D., Marley, Mark S., Cushing, Michael C., Sloan, G. C., ...
We present 10 - 19 um moderate resolution spectra of ten M dwarfs, one L dwarf, and two T dwarf systems obtained with the Infrared Spectrograph (IRS) onboard the Spitzer Space Telescope. The IRS...
Physical parameters of two very cool T dwarfs (2006)
Saumon, D., Marley, M. S., Leggett, S. K., Geballe, T. R., Stephens, D., Golimowski, D. A., ...
We present new infrared spectra of the T8 brown dwarf 2MASS J04151954-0935066: 2.9-4.1 micron spectra obtained with the Infrared Camera and Spectrograph on the Subaru Telescope, and 5.2-14.5 micron...
Leggett, S. K., Saumon, D., Marley, M. S., Geballe, T. R., Golimowski, D. A., Stephens, D., ...
We present new L' (3.75 um) photometry of six L and T dwarfs, and M' (4.70 um) photometry of ten L and T dwarfs, observed at Gemini Observatory, and new 3.55, 4.49, 5.73 and 7.87 um photometry of...
Found: The missing blue opacity in atmosphere models of cool hydrogen white dwarfs (2006)
We investigate the importance of the far red wing of the Lyman $ \alpha$ line of hydrogen in the atmospheres of cool white dwarfs of pure hydrogen composition. We find that this absorption process...
A Spitzer Infrared Spectrograph (IRS) Spectral Sequence of M, L, and T Dwarfs (2006)
Cushing, M. C., Roellig, T. L., Marley, M. S., Saumon, D., Leggett, S. K., Kirkpatrick, J. D., ...
We present a low-resolution (R = 90), 5.5-38 micron spectral sequence of a sample of M, L, and T dwarfs obtained with the Infrared Spectrograph (IRS) onboard the Spitzer Space Telescope. The spectra...
Ammonia as a tracer of chemical equilibrium in the T7.5 dwarf Gliese 570D (2006)
Saumon, D., Marley, M. S., Cushing, M. C., Leggett, S. K., Roellig, T. L., Lodders, K., ...
We present the first analysis of an optical to mid-infrared spectrum of the T7.5 dwarf Gliese 570D with model atmospheres, synthetic spectra, and brown dwarf evolution sequences. We obtain precise...
Dense plasmas in astrophysics: from giant planets to neutron stars (2005)
Chabrier, G., Saumon, D., Potekhin, A.
We briefly examine the properties of dense plasmas characteristic of the interior of giant planets and the atmospheres of neutron stars. Special attention is devoted to the equation of state of...
The Free-Free Opacity in Warm, Dense, and Weakly Ionized Helium (2005)
Kowalski, P. M., Mazevet, S., Saumon, D.
We investigate the ionization and the opacity of warm, dense helium under conditions found in the atmospheres of cool white dwarf stars. Our particular interest is in densities up to $\rm 3 g/cm^{3}$...
Atmosphere, Interior, and Evolution of the Metal-Rich Transiting Planet HD 149026b (2005)
Fortney, J. J., Saumon, D., Marley, M. S., Lodders, K., Freedman, R. S.
We investigate the atmosphere and interior of the new transiting planet HD 149026b, which appears to be very rich in heavy elements. We first compute model atmospheres at metallicities ranging from...
Comparative Planetary Atmospheres: Models of TrES-1 and HD209458b (2005)
Fortney, J. J., Marley, M. S., Lodders, K., Saumon, D., Freedman, R.
We present new self-consistent atmosphere models for transiting planets TrES-1 and HD209458b. The planets were recently observed with the Spitzer Space Telescope in bands centered on 4.5 and 8.0...
INSTITUTE OF PHYSICS PUBLISHING JOURNAL OF PHYSICS A: MATHEMATICAL AND GENERAL (2005)
G Chabrier, D Saumon, A Y Potekhin
Dense plasmas in astrophysics: from giant planets to
Kowalski, P. M., Saumon, D., Mazevet, S.
The atmospheres of cool, helium-rich white dwarfs constitute an exotic and poorly explored physical regime of stellar atmospheres. Under physical conditions where the temperature varies from $\rm...
The L to T Dwarf Transition (2004)
Marley, M. S., Cushing, M. C., Saumon, D.
While the precise mechanism responsible for the L to T dwarf transition remains unclear, it is clearly caused by changing cloud characteristics. Here we briefly review data relevant to understanding...
Spitzer Infrared Spectrograph Observations of M, L, and T Dwarfs (2004)
Roellig, T. L., Van Cleve, J. E., Sloan, G. C., Wilson, J. C., Saumon, D., Leggett, S. K., ...
We present the first mid-infrared spectra of brown dwarfs, together with observations of a low-mass star. Our targets are the M3.5 dwarf GJ 1001A, the L8 dwarf DENIS-P J0255-4700, and the T1/T6...
Shock Compression of Deuterium and the Interiors of Jupiter and Saturn (2004)
Recently, deuterium has been the focus of a high level of experimental and theoretical activity that was sparked by a disagreement on the experimental value of the maximum compression along the...
Radiative transfer in the refractive atmospheres of very cool white dwarfs (2004)
We consider the problem of radiative transfer in stellar atmospheres where the index of refraction departs from unity and is a function of density and temperature. We present modified Feautrier and...
The Mid-Infrared Spectra of Brown Dwarfs (2003)
Saumon, D., Marley, M. S., Lodders, K.
We present an analysis of brown dwarf model spectra in the mid-infrared spectral region (5 - 20 microns), in anticipation of data obtained with the Space Infrared Telescope Facility. The mid-infrared...
Search For Oxygen in Cool DQ White Dwarf Atmospheres (2002)
Kilic, M., Winget, D. E., Von Hippel, T., Lester, D. F., Saumon, D.
We report new infrared spectroscopic observations of cool DQ white dwarfs by using Coolspec on the 2.7m Harlan-Smith Telescope. DQs have helium-rich atmospheres with traces of molecular carbon...
Clouds and Clearings in the Atmospheres of the L and T Dwarfs (2002)
Marley, M. S., Ackerman, A., Burgasser, A. J., Saumon, D., Lodders, K., Freedman, R.
A sophisticated approach to condensate opacity is required to properly model the atmospheres of L and T dwarfs. Here we review different models for the treatment of condensates in brown dwarf...
Non-equilibrium chemistry in the atmospheres of brown dwarfs (2002)
Saumon, D., Marley, M. S., Lodders, K., Freedman, R. S.
Carbon monoxide and ammonia have been detected in the spectrum of Gl 229B at abundances that differ substantially from those obtained from chemical equilibrium. Vertical mixing in the atmosphere is a...
Oppenheimer, B. R., Hambly, N. C., Digby, A. P., Hodgkin, S. T., Saumon, D.
We reply to the criticism of Gibson & Flynn and of Graff regarding "Direct detection of galactic halo dark matter" by Oppenheimer et al. (2001) (Science, Vol. 292, p. 698), which reported on the...
Clouds and Chemistry: Ultracool Dwarf Atmospheric Properties from Optical and Infrared Colors (2001)
Marley, M. S., Seager, S., Saumon, D., Lodders, K., Ackerman, A. S., Freedman, R., ...
The optical and infrared colors of L and T dwarfs are sensitive to cloud sedimentation and chemical equilibrium processes in their atmospheres. The i'-z' vs. J-K color-color diagram provides a window...
Direct Detection of Galactic Halo Dark Matter (2001)
Oppenheimer, B. R., Hambly, N. C., Digby, A. P., Hodgkin, S. T., Saumon, D.
The Milky Way Galaxy contains a large, spherical component which is believed to harbor a substantial amount of unseen matter. Recent observations indirectly suggest that as much as half of this...
Infrared Observations and Modeling of one of the Coolest T Dwarfs, Gl 570D (2001)
Geballe, T. R., Saumon, D., Leggett, S. K., Knapp, G. R., Marley, M. S., Lodders, K.
We have obtained a good quality R$\sim$400 0.8-2.5 $\mu$m spectrum and accurate photometry of Gl 570D, one of the coolest and least luminous brown dwarfs currently known. The spectrum shows that Gl...
Observations of Ultracool White Dwarfs (2001)
Oppenheimer, B. R., Saumon, D., Hodgkin, S. T., Jameson, R. F., Hambly, N. C., Chabrier, G., ...
We present new spectroscopic and photometric measurements of the white dwarfs LHS 3250 and WD 0346+246. Along with F351-50, these white dwarfs are the coolest ones known, all with effective...
The ages of very cool hydrogen-rich white dwarfs (2000)
Salaris, M., Garcia-Berro, E., Hernanz, M., Isern, J., Saumon, D.
The evolution of white dwarfs is essentially a cooling process that depends primarily on the energy stored in their degenerate cores and on the transparency of their envelopes. In this paper we...
Molecular Abundances in the Atmosphere of the T Dwarf Gl 229B (2000)
Saumon, D., Geballe, T. R., Leggett, S. K., Marley, M. S., Freedman, R. S., Lodders, K., ...
We present new, high resolution, infrared spectra of the T dwarf Gliese 229B in the J, H, and K bandpasses. We analyze each of these as well as previously published spectra to determine its...
On the Radii of Close-in Giant Planets (2000)
Burrows, A., Guillot, T., Hubbard, W. B., Marley, M. S., Saumon, D., Lunine, J. I., ...
The recent discovery that the close-in extrasolar giant planet, HD209458b, transits its star has provided a first-of-its-kind measurement of the planet's radius and mass. In addition, there is a...
Modeling Pressure-Ionization of Hydrogen in the Context of Astrophysics (1999)
Saumon, D., Chabrier, G., Wagner, D. J., Xie, X.
The recent development of techniques for laser-driven shock compression of hydrogen has opened the door to the experimental determination of its behavior under conditions characteristic of stellar...
Pure hydrogen atmosphere for very cool white dwarfs (1998)
Microlensing events observed in the line of sight toward the LMC indicate that a significant fraction of the mass of the dark halo of the Galaxy is probably composed of white dwarfs. In addition,...
New Ideas in the Theory of Extrasolar Giant Planets and Brown Dwarfs (1998)
Burrows, Adam, Hubbard, W. B., Lunine, J. I., Marley, M., Saumon, D.
We summarize and extend recent work on the theory of extrasolar giant planets (EGPs) and brown dwarfs, paying particular attention to Gliese 229 B, the albedos of EGPs, the compositions of substellar...
The Spectral Character of Giant Planets and Brown Dwarfs (1997)
Burrows, A., Marley, M., Hubbard, W. B., Sudarsky, D., Sharp, C., Lunine, J. I., ...
Since October of 1995, employing Doppler spectroscopy astronomers have discovered as many as 20 giant planets and brown dwarfs, including companions to $\tau$ Boo, 51 Peg, $\upsilon$ And, 55 Cnc,...
Advances in the Theory of Extrasolar Giant Planets and Brown Dwarfs (1997)
Burrows, A., Sudarsky, D., Sharp, C., Marley, M., Hubbard, W. B., Lunine, J. I., ...
We have developed a new non-gray theory of the evolution, spectra, and colors of extrasolar giant planets (EGPs) and brown dwarfs that reveals their exotic nature and uniqueness. We have discovered...
A Non-Gray Theory of Extrasolar Giant Planets and Brown Dwarfs (1997)
Burrows, A., Marley, M., Hubbard, W. B., Lunine, J. I., Guillot, T., Saumon, D., ...
We present the results of a new series of non-gray calculations of the atmospheres, spectra, colors, and evolution of extrasolar giant planets (EGPs) and brown dwarfs for effective temperatures below...
Extrasolar Giant Planet and Brown Dwarf Models (1997)
Burrows, A., Hubbard, W. B., Lunine, J. I., Guillot, M. Marley T., Saumon, D., Freedman, R. S.
With the discovery of the companions of 51 Peg, 55 Cnc, $\tau$ Boo, $\upsilon$ And, 70 Vir, 47 UMa, and Gl229, evolutionary and spectral models of gas giants and/or brown dwarfs with masses from 0.3...
Liquid metallic hydrogen and the structure of brown dwarfs and giant planets (1997)
Hubbard, W. B., Guillot, T., Lunine, J. I., Burrows, A., Saumon, D., Marley, M. S., ...
Electron-degenerate, pressure-ionized hydrogen (usually referred to as metallic hydrogen) is the principal constituent of brown dwarfs, the long-sought objects which lie in the mass range between the...
Theortetical Models of Extrasolar Giant Planets (1996)
Burrows, A., Hubbard, W. B., Lunine, J. I., Guillot, T., Saumon, D., Marley, M., ...
The recent discoveries of giant planets around nearby stars have galvanized the planetary science community, astronomers, and the public at large. Since {\it direct} detection is now feasible, and is...
Atmospheric, Evolutionary, and Spectral Models of the Brown Dwarf Gliese 229 B (1996)
Marley, M. S., Saumon, D., Guillot, T., Freedman, R. S., Hubbard, W. B., Burrows, A., ...
Theoretical spectra and evolutionary models that span the giant planet--brown dwarf continuum have been computed based on the recent discovery of the brown dwarf, Gliese 229 B. A flux enhancement in...
Giant Planets at Small Orbital Distances (1995)
Guillot, T., Burrows, A., Hubbard, W. B., Lunine, J. I., Saumon, D.
Using Doppler spectroscopy to detect the reflex motion of the nearby star, 51 Pegasi, Mayor \& Queloz (1995) claim to have discovered a giant planet in a 0.05-A.U., 4.23-day orbit. They estimate its...
A Theory of Extrasolar Giant Planets (1995)
Saumon, D., Hubbard, W. B., Burrows, A., Guillot, T., Lunine, J. I., Chabrier, G.
We present a broad suite of models of extrasolar giant planets (EGP's), ranging in mass from 0.3 to 15 Jupiter masses. The models predict luminosity (both reflected and emitted) as a function of age,...
Prospects for Detection of Extra-Solar Giant Planets by Next-Generation Telescopes (1995)
Burrows, A., Saumon, D., Guillot, T., Hubbard, W. B., Lunine, J. I.
Interest among astronomers in the detection of extra-solar planets is accelerating with the growing realization that it may soon be technically feasible. The ongoing renaissance in telescope...