* Astronomy

Title: Atmospheric Circulation of Exoplanets
Authors: Adam P. Showman, James Y-K. Cho, Kristen Menou

We survey the basic principles of atmospheric dynamics relevant to explaining existing and future observations of exoplanets, both gas giant and terrestrial. Given the paucity of data on exoplanet atmospheres, our approach is to emphasize fundamental principles and insights gained from Solar-System studies that are likely to be generalisable to exoplanets. We begin by presenting the hierarchy of basic equations used in atmospheric dynamics, including the Navier-Stokes, primitive, shallow-water, and two-dimensional nondivergent models. We then survey key concepts in atmospheric dynamics, including the importance of planetary rotation, the concept of balance, and scaling arguments to show how turbulent interactions generally produce large-scale east-west banding on rotating planets. We next turn to issues specific to giant planets, including their expected interior and atmospheric thermal structures, the implications for their wind patterns, and mechanisms to pump their east-west jets. Hot Jupiter atmospheric dynamics are given particular attention, as these close-in planets have been the subject of most of the concrete developments in the study of exoplanetary atmospheres. We then turn to the basic elements of circulation on terrestrial planets as inferred from Solar-System studies, including Hadley cells, jet streams, processes that govern the large-scale horizontal temperature contrasts, and climate, and we discuss how these insights may apply to terrestrial exoplanets. Although exoplanets surely possess a greater diversity of circulation regimes than seen on the planets in our Solar System, our guiding philosophy is that the multi-decade study of Solar-System planets reviewed here provides a foundation upon which our understanding of more exotic exoplanetary meteorology must build.

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Title: Exoplanet Characterisation and the Search for Life
Authors: J. Kasting, W. Traub, A. Roberge, A. Leger, A. Schwartz, A. Wooten, A. Vosteen, A. Lo, A. Brack, A. Tanner, A. Coustenis, B. Lane, B. Oppenheimer, B. Mennesson, B. Lopez, C. Grillmair, C. Beichman, C. ****ell, C. Hanot, C. McCarthy, C. Stark, C. Marois, C. Aime, D. Angerhausen, D. Montes, D. Wilner, D. Defrere, D. Mourard, D. Lin, E. Kite, E. Chassefiere, F. Malbet, F. Tian, F. Westall, G. Illingworth, G. Vasisht, G. Serabyn, G. Marcy, G. Bryden, G. White, G. Laughlin, G. Torres, H. Hammel, H. Ferguson, H. Shibai, H. Rottgering, J. Surdej, J. Wiseman, J. Ge, J. Bally, J. Krist, J. Monnier, J. Trauger, J. Horner, J. Catanzarite, J. Harrington, J. Nishikawa, K. Stapelfeldt, K. von Braun, K. Biazzo, K. Carpenter, K. Balasubramanian, L. Kaltenegger, M. Postman, M. Spaans, M. Turnbull, M. Levine,
M. Burchell, M. Ealey, M. Kuchner, M. Marley, M. Dominik, M. Mountain, M. Kenworthy, M. Muterspaugh, M. Shao, M. Zhao, M. Tamura, N. Kasdin, N. Haghighipour, N. Kiang, N. Elias, N. Woolf, N. Mason, O. Absil, O. Guyon, O. Lay, P. Borde, P. Fouque, P. Kalas, P. Lowrance, P. Plavchan, P. Hinz, P. Kervella, P. Chen, R. Akeson, R. Soummer, R. Waters, R. Barry, R. Kendrick, R. Brown, R. Vanderbei, R. Woodruff, R. Danner, R. Allen, R. Polidan, S. Seager, S. MacPhee, S. Hosseini, S. Metchev, S. Kafka, S. Ridgway, S. Rinehart, S. Unwin, S. Shaklan, T. ten Brummelaar, T. Mazeh, V. Meadows, W. Weiss, W. Danchi, W. Ip, Y. Rabbia
et al. (55 additional authors not shown)

Over 300 extrasolar planets (exoplanets) have been detected orbiting nearby stars. We now hope to conduct a census of all planets around nearby stars and to characterize their atmospheres and surfaces with spectroscopy. Rocky planets within their star's habitable zones have the highest priority, as these have the potential to harbour life. Our science goal is to find and characterise all nearby exoplanets; this requires that we measure the mass, orbit, and spectroscopic signature of each one at visible and infrared wavelengths. The techniques for doing this are at hand today. Within the decade we could answer long-standing questions about the evolution and nature of other planetary systems, and we could search for clues as to whether life exists elsewhere in our galactic neighbourhood.

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Exoplanets Clue to Sun's Curious Chemistry
A ground-breaking census of 500 stars, 70 of which are known to host planets, has successfully linked the long-standing "lithium mystery" observed in the Sun to the presence of planetary systems. Using ESO's successful HARPS spectrograph, a team of astronomers has found that Sun-like stars that host planets have destroyed their lithium much more efficiently than "planet-free" stars. This finding does not only shed light on the lack of lithium in our star, but also provides astronomers with a very efficient way of finding stars with planetary systems.

"For almost 10 years we have tried to find out what distinguishes stars with planetary systems from their barren cousins. We have now found that the amount of lithium in Sun-like stars depends on whether or not they have planets" - Garik Israelian, lead author of a paper appearing this week in the journal Nature.

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Planets 'spotted' outside our own galaxy for first time
Discoveries of exoplanets within the Milky Way have been happening regularly for some years now, with 403 found since the first one was spotted in 1995.
However, scientists studying remote galaxies, some up to 10 billion light years away, believe they have seen signs of planetary formation within them the first such evidence found.

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Ed ~ An Exoplanet had already been found in the Andromeda Galaxy (June 24 2009)

Title: Formation of massive planets in binary star systems
Authors: Willy Kley (1), ((1) University of Tuebingen)

As of today over 40 planetary systems have been discovered in binary star systems. In all cases the configuration appears to be circumstellar, where the planets orbit around one of the stars, the secondary acting as a perturber. The formation of planets in binary star systems is more difficult than around single stars due to the gravitational action of the companion on the dynamics of the protoplanetary disk. In this contribution we first briefly present the relevant observational evidence for planets in binary systems. Then the dynamical influence that a secondary companion has on a circumstellar disk will be analysed through fully hydrodynamical simulations. We demonstrate that the disk becomes eccentric and shows a coherent precession around the primary star. Finally, fully hydrodynamical simulations of evolving protoplanets embedded in disks in binary star systems are presented. We investigate how the orbital evolution of protoplanetary embryos and their mass growth from cores to massive planets might be affected in this very dynamical environment. We consider, in particular, the planet orbiting the primary in the system Gamma Cephei.

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Title: Naming the extrasolar planets
Authors: W. Lyra
(Version v2)

Extrasolar planets are not named and are referred to only by their assigned scientific designation. The reason given by the IAU to not name the planets is that it is considered impractical as planets are expected to be common. I advance some reasons as to why this logic is flawed, and suggest names for the 403 extrasolar planet candidates known as of Oct 2009, based on the continued tradition of names from Roman-Greek mythology.

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Ed ~ This would not be endorsed by the IAU.