solar occultation observed by Cassini/VIMS: gas absorption and constraints on aerosol composition, Icarus (2009), doi: 10.1016/j.icarus.2008.12.024 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. Fractal aggregates with more than 1 000 spheres of radius 0.05 µm are needed to fit the data.Clear differences in the chemical composition are revealed between tholins and actual haze particles. Extinction and density profiles are also retrieved using an inversion of the continuum values. An exponential increase of the haze number density is observed under 420 km with a typical scale height of 60 km.

[1] We report the observation of two stellar occultations by Titan on 14 November 2003, using stations in the Indian Ocean, southern Africa, Spain, and northern and southern Americas. These occultations probed altitudes between $550 and 250 km ($1 to 250 mbar) in Titan's upper stratosphere. The light curves reveal a sharp inversion layer near 515 ± 6 km altitude (1.5 mbar pressure level), where the temperature increases by 15 K in only 6 km. This layer is close to an inversion layer observed fourteen months later by the Huygens HASI instrument during the entry of the probe in Titan's atmosphere on 14 January 2005 [Fulchignoni et al., 2005]. Central flashes observed during the first occultation provide constraints on the zonal wind regime at 250 km, with a strong northern jet ($200 m s À1 ) around the latitude 55°N, wind velocities of $150 m s À1 near the equator, and progressively weaker winds as more southern latitudes are probed. The haze distribution around Titan's limb at 250 km altitude is close to that predicted by the Global Circulation Model of Rannou et al. (2004) in the southern hemisphere, but a clearing north of 40°N is necessary to explain our data. This contrasts with Rannou et al.'s (2004) model, which predicts a very thick polar hood over Titan's northern polar regions. Simultaneous observations of the flashes at various wavelengths provide a dependence of t / l Àq , with q = 1.8 ± 0.5 between 0.51 and 2.2 mm for the tangential optical depth of the hazes at 250 km altitude.

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Pluto and its satellite, Charon (discovered in 1978; ref. 1), appear to form a double planet, rather than a hierarchical planet/satellite couple. Charon is about half Pluto's size and about one-eighth its mass. The precise radii of Pluto and Charon have remained uncertain, leading to large uncertainties on their densities. Although stellar occultations by Charon are in principle a powerful way of measuring its size, they are rare, as the satellite subtends less than 0.3 microradians (0.06 arcsec) on the sky. One occultation (in 1980) yielded a lower limit of 600 km for the satellite's radius, which was later refined to 601.5 km (ref. 4). Here we report observations from a multi-station stellar occultation by Charon, which we use to derive a radius, R(C) = 603.6 +/- 1.4 km (1sigma), and a density of rho = 1.71 +/- 0.08 g cm(-3). This occultation also provides upper limits of 110 and 15 (3sigma) nanobar for an atmosphere around Charon, assuming respectively a pure nitrogen or pure methane atmosphere.

ForewordThis book, entitled "The CoRoT Legacy Book", is dedicated to all the people interested in the CoRoT mission and the beautiful data that were delivered during its six-year duration. Either amateurs, professional, young or senior researchers find treasures not only at the time of this publication but also in twenty or thirty years ahead.It presents the data in their final version, explains how they have been obtained, how to handle them, describes the tools necessary to understand them, and where to find them. It also highlights the most striking first results obtained up to now. CoRoT has opened several unexpected directions of research and certainly new ones still to be discovered.The book consists in 5 Parts, divided into chapters which can be used and also downloaded separately. Part I recalls the successive steps followed by the scientists and shows that it took a long time to promote this new domain of ultra-high precision and long-duration stellar photometry from space. As it was indeed rapidly understood that this type of research could only be done from space, this domain entered the wild competition of space mission selection. Fortunately, however, this long period of maturation brought about several selections in different countries and opened the way for future more ambitious projects, as described in Part V.Part II is dedicated to the data themselves. Chapter 1 presents the observing program achieved over the 6 yr of operation, the choice of the regions to be observed, the target selection and the tunings of the instrumental settings, very important indeed to understand the data.Chapters 2 and 3 describe the successive steps of correction necessary to get rid of the spurious instrumental perturbations, and to obtain the required precision, which has largely overpassed the requirements. Chapter 4 explains how to use the "Ready to use" N2 data, and Chapter 5 where to find them.Parts III and IV enlighten several major results, in the main directions, addressed by CoRoT:

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