Exoplanet atmospheres

Abstract:

We report 0.5"x0.9" resolution, interferometric observations of the 1.3 mm CO J=2-1 line in the infrared luminous galactic merger NGC 6240. About half of the CO flux is concentrated in a rotating but highly turbulent, thick disk structure centered between the two radio and near-infrared nuclei. A number of gas features connect this ~500 pc diameter central disk to larger scales. Throughout this region the molecular gas has local velocity widths which exceed 300 km/s FWHM and even reach FWZP line widths of 1000 km/s in a number of directions. The mass of the central gas concentration constitutes a significant fraction of the dynamical mass, M_gas(R<470 pc) ~ 2-4x10^9 M_o ~ 0.3-0.7 M_dyn. We conclude that NGC 6240 is in an earlier merging stage than the prototypical ultraluminous galaxy, Arp 220. The interstellar gas in NGC 6240 is in the process of settling between the two progenitor stellar nuclei, is dissipating rapidly and will likely form a central thin disk. In the next merger stage, NGC 6240 may well experience a major starburst like that observed in Arp 220.

Abstract:

The understanding of the composition and cloud structure has advanced greatly in the last few years and in particular was greatly improved upon following the highly successful Pioneer and Voyager missions to that planet. Recently the Galileo spacecraft has gone into orbit about Jupiter and its remote sensing instruments, including the Near Infrared Mapping Spectrometer (NIMS) and the Solid State Imager (SSI), have yielded exciting new details of the spatial and vertical structure of the Jovian clouds and volatiles. At the same time Galileo's entry probe has made the first ever in situ measurements of conditions in the atmosphere. Recent ground-based observations have also added to the body of evidence from which conditions in the Jovian atmosphere may be inferred. This paper aims to review the current understanding of the composition and cloud structure of Jupiter's atmosphere in the light of the new Galileo results and recent ground-based, and earth-orbiting telescope observations.