The last few years has seen a dramatic increase in the number of exoplanets known and in the range of methods for characterising their atmospheric properties. At the same time, new discoveries of increasingly cooler brown dwarfs have pushed down thei
r temperature range which now extends down to Y-dwarfs of <300 K. Modelling of these atmospheres has required the development of new techniques to deal with the molecular chemistry and clouds in these objects. The atmospheres of brown dwarfs are relatively well understood, but some problems remain, in particular the behavior of clouds at the L/T transition. Observational data for exoplanet atmosphere characterization is largely limited to giant exoplanets that are hot because they are near to their star (hot Jupiters) or because they are young and still cooling. For these planets there is good evidence for the presence of CO and H2O absorptions in the IR. Sodium absorption is observed in a number of objects. Reflected light measurements show that some giant exoplanets are very dark, indicating a cloud free atmosphere. However, there is also good evidence for clouds and haze in some other planets. It is also well established that some highly irradiated planets have inflated radii, though the mechanism for this inflation is not yet clear. Some other issues in the composition and structure of giant exoplanet atmospheres such as the occurence of inverted temperature structures, the presence or absence of CO2 and CH4, and the occurrence of high C/O ratios are still the subject of investigation and debate.
We have obtained spatially resolved spectra of Titan in the near-infrared J, H and K bands at a resolving power of ~5000 using the near-infrared integral field spectrometer (NIFS) on the Gemini North 8m telescope. Using recent data from the Cassini/H
uygens mission on the atmospheric composition and surface and aerosol properties, we develop a multiple-scattering radiative transfer model for the Titan atmosphere. The Titan spectrum at these wavelengths is dominated by absorption due to methane with a series of strong absorption band systems separated by window regions where the surface of Titan can be seen. We use a line-by-line approach to derive the methane absorption coefficients. The methane spectrum is only accurately represented in standard line lists down to ~2.1 {mu}m. However, by making use of recent laboratory data and modeling of the methane spectrum we are able to construct a new line list that can be used down to 1.3 {mu}m. The new line list allows us to generate spectra that are a good match to the observations at all wavelengths longer than 1.3 {mu}m and allow us to model regions, such as the 1.55 {mu}m window that could not be studied usefully with previous line lists such as HITRAN 2008. We point out the importance of the far-wing line shape of strong methane lines in determining the shape of the methane windows. Line shapes with Lorentzian, and sub-Lorentzian regions are needed to match the shape of the windows, but different shape parameters are needed for the 1.55 {mu}m and 2 {mu}m windows. After the methane lines are modelled our observations are sensitive to additional absorptions, and we use the data in the 1.55 {mu}m region to determine a D/H ratio of 1.77 pm 0.20 x 10-4, and a CO mixing ratio of 50 pm 11 ppmv. In the 2 {mu}m window we detect absorption features that can be identified with the { u}5+3{ u}6 and 2{ u}3+2{ u}6 bands of CH3D.
Precision Doppler velocity measurements from the Anglo-Australian Tele- scope reveal a planet with a 9.4+/-0.4 year period orbiting the M1.5 dwarf GJ 832. Within measurement uncertainty the orbit is circular, and the minimum mass (m sin i) of the pla
net is 0.64+/-0.06 MJUP. GJ 832 appears to be depleted in met- als by at least 50% relative to the Sun, as are a significant fraction of the M dwarfs known to host exoplanets. GJ 832 adds another Jupiter-mass planet to the known census of M dwarf exoplanets, which currently includes a significant number of Neptune-mass planets. GJ 832 is an excellent candidate for astromet- ric orbit determination with alpha sin i = 0.95 mas. GJ 832b has the second largest angular distance from its star among radial velocity detected exoplanets (0.69 arc sec) making it a potentially interesting target for future direct detection.
