Beschreibung: WASP-80b is a missing link in the study of exoatmospheres. It falls between the warm Neptunes and the hot Jupiters and is amenable for characterization, thanks to its host star's properties. We observed the planet through transit and during occultation with Warm Spitzer . Combining our mid-infrared transits with optical time series, we find that the planet presents a transmission spectrum indistinguishable from a horizontal line. In emission, WASP-80b is the intrinsically faintest planet whose dayside flux has been detected in both the 3.6 and 4.5 μm Spitzer channels. The depths of the occultations reveal that WASP-80b is as bright and as red as a T4 dwarf, but that its temperature is cooler. If planets go through the equivalent of an L–T transition, our results would imply that this happens at cooler temperatures than for brown dwarfs. Placing WASP-80b's dayside into a colour–magnitude diagram, it falls exactly at the junction between a blackbody model and the T-dwarf sequence; we cannot discern which of those two interpretations is the more likely. WASP-80b's flux density is as low as GJ 436b at 3.6 μm; the planet's dayside is also fainter, but bluer than HD 189733Ab's nightside (in the [3.6] and [4.5] Spitzer bands). Flux measurements on other planets with similar equilibrium temperatures are required to establish whether irradiated gas giants, such as brown dwarfs, transition between two spectral classes. An eventual detection of methane absorption in transmission would also help lift that degeneracy. We obtained a second series of high-resolution spectra during transit, using HARPS. We reanalyse the Rossiter–McLaughlin effect. The data now favour an aligned orbital solution and a stellar rotation nearly three times slower than stellar line broadening implies. A contribution to stellar line broadening, maybe macroturbulence, is likely to have been underestimated for cool stars, whose rotations have therefore been systematically overestimated.

Beschreibung: Exoplanets orbiting close to their parent stars may lose some fraction of their atmospheres because of the extreme irradiation. Atmospheric mass loss primarily affects low-mass exoplanets, leading to the suggestion that hot rocky planets might have begun as Neptune-like, but subsequently lost all of their atmospheres; however, no confident measurements have hitherto been available. The signature of this loss could be observed in the ultraviolet spectrum, when the planet and its escaping atmosphere transit the star, giving rise to deeper and longer transit signatures than in the optical spectrum. Here we report that in the ultraviolet the Neptune-mass exoplanet GJ 436b (also known as Gliese 436b) has transit depths of 56.3 +/- 3.5% (1sigma), far beyond the 0.69% optical transit depth. The ultraviolet transits repeatedly start about two hours before, and end more than three hours after the approximately one hour optical transit, which is substantially different from one previous claim (based on an inaccurate ephemeris). We infer from this that the planet is surrounded and trailed by a large exospheric cloud composed mainly of hydrogen atoms. We estimate a mass-loss rate in the range of about 10(8)-10(9) grams per second, which is far too small to deplete the atmosphere of a Neptune-like planet in the lifetime of the parent star, but would have been much greater in the past.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Ehrenreich, David -- Bourrier, Vincent -- Wheatley, Peter J -- des Etangs, Alain Lecavelier -- Hebrard, Guillaume -- Udry, Stephane -- Bonfils, Xavier -- Delfosse, Xavier -- Desert, Jean-Michel -- Sing, David K -- Vidal-Madjar, Alfred -- England -- Nature. 2015 Jun 25;522(7557):459-61. doi: 10.1038/nature14501.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Observatoire de l'Universite de Geneve, 51 chemin des Maillettes, 1290 Versoix, Switzerland. ; Department of Physics, University of Warwick, Coventry CV4 7AL, UK. ; 1] CNRS, UMR 7095, Institut d'Astrophysique de Paris, 98 bis boulevard Arago, 75014 Paris, France [2] Sorbonnes Universites, UPMC Univ. Paris 6, UMR 7095, Institut d'Astrophysique de Paris, 98 bis boulevard Arago, 75014 Paris, France. ; 1] CNRS, UMR 7095, Institut d'Astrophysique de Paris, 98 bis boulevard Arago, 75014 Paris, France [2] Sorbonnes Universites, UPMC Univ. Paris 6, UMR 7095, Institut d'Astrophysique de Paris, 98 bis boulevard Arago, 75014 Paris, France [3] Observatoire de Haute-Provence, CNRS &OAMP, 04870 Saint-Michel-l'Observatoire, France. ; 1] Univ. Grenoble Alpes, IPAG, F-38000 Grenoble, France [2] CNRS, IPAG, F-38000 Grenoble, France. ; CASA, Department of Astrophysical &Planetary Sciences, University of Colorado, 389-UCB, Boulder, Colorado 80309, USA. ; Astrophysics Group, School of Physics, University of Exeter, Stocker Road, Exeter EX4 4QL, UK.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/26108854" target="_blank"〉PubMed〈/a〉

Beschreibung: In the 1980s, excess infrared emission was discovered around main-sequence stars; subsequent direct-imaging observations revealed orbiting disks of cold dust to be the source. These 'debris disks' were thought to be by-products of planet formation because they often exhibited morphological and brightness asymmetries that may result from gravitational perturbation by planets. This was proved to be true for the beta Pictoris system, in which the known planet generates an observable warp in the disk. The nearby, young, unusually active late-type star AU Microscopii hosts a well-studied edge-on debris disk; earlier observations in the visible and near-infrared found asymmetric localized structures in the form of intensity variations along the midplane of the disk beyond a distance of 20 astronomical units. Here we report high-contrast imaging that reveals a series of five large-scale features in the southeast side of the disk, at projected separations of 10-60 astronomical units, persisting over intervals of 1-4 years. All these features appear to move away from the star at projected speeds of 4-10 kilometres per second, suggesting highly eccentric or unbound trajectories if they are associated with physical entities. The origin, localization, morphology and rapid evolution of these features are difficult to reconcile with current theories.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Boccaletti, Anthony -- Thalmann, Christian -- Lagrange, Anne-Marie -- Janson, Markus -- Augereau, Jean-Charles -- Schneider, Glenn -- Milli, Julien -- Grady, Carol -- Debes, John -- Langlois, Maud -- Mouillet, David -- Henning, Thomas -- Dominik, Carsten -- Maire, Anne-Lise -- Beuzit, Jean-Luc -- Carson, Joseph -- Dohlen, Kjetil -- Engler, Natalia -- Feldt, Markus -- Fusco, Thierry -- Ginski, Christian -- Girard, Julien H -- Hines, Dean -- Kasper, Markus -- Mawet, Dimitri -- Menard, Francois -- Meyer, Michael R -- Moutou, Claire -- Olofsson, Johan -- Rodigas, Timothy -- Sauvage, Jean-Francois -- Schlieder, Joshua -- Schmid, Hans Martin -- Turatto, Massimo -- Udry, Stephane -- Vakili, Farrokh -- Vigan, Arthur -- Wahhaj, Zahed -- Wisniewski, John -- England -- Nature. 2015 Oct 8;526(7572):230-2. doi: 10.1038/nature15705.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉LESIA, Observatoire de Paris, CNRS, Universite Paris Diderot, Universite Pierre et Marie Curie, 5 place Jules Janssen, 92190 Meudon, France. ; ETH Zurich, Institute for Astronomy, Wolfgang-Pauli-Strasse 27, CH-8093 Zurich, Switzerland. ; Universite Grenoble Alpes, IPAG, F-38000 Grenoble, France. ; CNRS, IPAG, F-38000 Grenoble, France. ; Department of Astronomy, Stockholm University, SE-106 91 Stockholm, Sweden. ; Max-Planck-Institut fur Astronomie, Konigstuhl 17, D-69117 Heidelberg, Germany. ; Steward Observatory, 933 North Cherry Avenue, The University of Arizona, Tucson, Arizona 85721, USA. ; European Southern Observatory (ESO), Alonso de Cordova 3107, Vitacura, Casilla 19001, Santiago, Chile. ; Eureka Scientific, 2452 Delmer, Suite 100, Oakland, California 96002, USA. ; Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, Maryland 21218, USA. ; Centre de Recherche Astrophysique de Lyon, (CNRS/ENS-L/Universite Lyon 1), 9 avenue Charles Andre, 69561 Saint-Genis-Laval, France. ; Aix Marseille Universite, CNRS, LAM (Laboratoire d'Astrophysique de Marseille) UMR 7326, 13388 Marseille, France. ; University of Amsterdam, Anton Pannekoek Institute for Astronomy, Science Park 904 1098 XH Amsterdam, The Netherlands. ; INAF-Osservatorio Astronomico di Padova, Vicolo dell'Osservatorio 5, 35122 Padova, Italy. ; Department of Physics and Astronomy, College of Charleston, South Carolina, 29424, USA. ; ONERA-The French Aerospace Laboratory, 92322 Chatillon, France. ; Sterrewacht Leiden, PO Box 9513, Niels Bohrweg 2, NL-2300RA Leiden, The Netherlands. ; European Southern Observatory (ESO), Karl Schwarzschild Strasse 2, 85748 Garching bei Munchen, Germany. ; Department of Astronomy, California Institute of Technology, 1200 East California Boulevard, MC 249-17, Pasadena, California 91125, USA. ; UMI-FCA, CNRS/INSU France (UMI 3386), and Departamento de Astronomia, Universidad de Chile, Casilla 36-D, Correo Central, Santiago, Chile. ; Department of Terrestrial Magnetism, Carnegie Institution of Washington, 5241 Broad Branch Road NW, Washington DC 20015, USA. ; NASA Ames Research Center, Space Science and Astrobiology Division, MS 245-6, Moffett Field, California 94035, USA. ; Observatoire de Geneve, University of Geneva, 51 Chemin des Maillettes, 1290 Versoix, Switzerland. ; Laboratoire J.-L. Lagrange, Observatoire de la Cote d'Azur (OCA), Universite de Nice-Sophia Antipolis (UNS), CNRS, Campus Valrose, 06108 Nice Cedex 2, France. ; Department of Physics and Astronomy, University of Oklahoma, 440 West Brooks Street, Norman, Oklahoma 73019, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/26450055" target="_blank"〉PubMed〈/a〉

Beschreibung: M-dwarf stars--hydrogen-burning stars that are smaller than 60 per cent of the size of the Sun--are the most common class of star in our Galaxy and outnumber Sun-like stars by a ratio of 12:1. Recent results have shown that M dwarfs host Earth-sized planets in great numbers: the average number of M-dwarf planets that are between 0.5 to 1.5 times the size of Earth is at least 1.4 per star. The nearest such planets known to transit their star are 39 parsecs away, too distant for detailed follow-up observations to measure the planetary masses or to study their atmospheres. Here we report observations of GJ 1132b, a planet with a size of 1.2 Earth radii that is transiting a small star 12 parsecs away. Our Doppler mass measurement of GJ 1132b yields a density consistent with an Earth-like bulk composition, similar to the compositions of the six known exoplanets with masses less than six times that of the Earth and precisely measured densities. Receiving 19 times more stellar radiation than the Earth, the planet is too hot to be habitable but is cool enough to support a substantial atmosphere, one that has probably been considerably depleted of hydrogen. Because the host star is nearby and only 21 per cent the radius of the Sun, existing and upcoming telescopes will be able to observe the composition and dynamics of the planetary atmosphere.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Berta-Thompson, Zachory K -- Irwin, Jonathan -- Charbonneau, David -- Newton, Elisabeth R -- Dittmann, Jason A -- Astudillo-Defru, Nicola -- Bonfils, Xavier -- Gillon, Michael -- Jehin, Emmanuel -- Stark, Antony A -- Stalder, Brian -- Bouchy, Francois -- Delfosse, Xavier -- Forveille, Thierry -- Lovis, Christophe -- Mayor, Michel -- Neves, Vasco -- Pepe, Francesco -- Santos, Nuno C -- Udry, Stephane -- Wunsche, Anael -- England -- Nature. 2015 Nov 12;527(7577):204-7. doi: 10.1038/nature15762.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, USA. ; Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, Massachusetts 02138, USA. ; Observatoire de Geneve, Universite de Geneve, 51 chemin des Maillettes, 1290 Sauverny, Switzerland. ; Universite Grenoble Alpes, IPAG, F-38000 Grenoble, France. ; CNRS, IPAG, F-38000 Grenoble, France. ; Institut d'Astrophysique et de Geophysique, Universite de Liege, Allee du 6 Aout 17, Batiment B5C, 4000 Liege, Belgium. ; Institute for Astronomy, University of Hawaii at Manoa, Honolulu, Hawaii 96822, USA. ; Laboratoire d'Astrophysique de Marseille, UMR 6110 CNRS, Universite de Provence, 38 rue Frederic Joliot-Curie, 13388, Marseille Cedex 13, France. ; Departamento de Fisica, Universidade Federal do Rio Grande do Norte, 59072-970 Natal, Rio Grande do Norte, Brazil. ; Instituto de Astrofisica e Ciencias do Espaco, Universidade do Porto, CAUP, Rua das Estrelas, 4150-762 Porto, Portugal. ; Departamento de Fisica e Astronomia, Faculdade de Ciencias, Universidade do Porto, Rua Campo Alegre, 4169-007 Porto, Portugal.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/26560298" target="_blank"〉PubMed〈/a〉

Beschreibung: Exoplanets down to the size of Earth have been found, but not in the habitable zone--that is, at a distance from the parent star at which water, if present, would be liquid. There are planets in the habitable zone of stars cooler than our Sun, but for reasons such as tidal locking and strong stellar activity, they are unlikely to harbour water-carbon life as we know it. The detection of a habitable Earth-mass planet orbiting a star similar to our Sun is extremely difficult, because such a signal is overwhelmed by stellar perturbations. Here we report the detection of an Earth-mass planet orbiting our neighbour star alpha Centauri B, a member of the closest stellar system to the Sun. The planet has an orbital period of 3.236 days and is about 0.04 astronomical units from the star (one astronomical unit is the Earth-Sun distance).〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Dumusque, Xavier -- Pepe, Francesco -- Lovis, Christophe -- Segransan, Damien -- Sahlmann, Johannes -- Benz, Willy -- Bouchy, Francois -- Mayor, Michel -- Queloz, Didier -- Santos, Nuno -- Udry, Stephane -- England -- Nature. 2012 Nov 8;491(7423):207-11. doi: 10.1038/nature11572. Epub 2012 Oct 17.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Observatoire de Geneve, Universite de Geneve, 51 chemin des Maillettes, CH-1290 Sauverny, Switzerland. xavier.dumusque@unige.ch〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/23075844" target="_blank"〉PubMed〈/a〉

Beschreibung: Recent analyses of data from the NASA Kepler spacecraft have established that planets with radii within 25 per cent of the Earth's (R Earth symbol) are commonplace throughout the Galaxy, orbiting at least 16.5 per cent of Sun-like stars. Because these studies were sensitive to the sizes of the planets but not their masses, the question remains whether these Earth-sized planets are indeed similar to the Earth in bulk composition. The smallest planets for which masses have been accurately determined are Kepler-10b (1.42 R Earth symbol) and Kepler-36b (1.49 R Earth symbol), which are both significantly larger than the Earth. Recently, the planet Kepler-78b was discovered and found to have a radius of only 1.16 R Earth symbol. Here we report that the mass of this planet is 1.86 Earth masses. The resulting mean density of the planet is 5.57 g cm(-3), which is similar to that of the Earth and implies a composition of iron and rock.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Pepe, Francesco -- Cameron, Andrew Collier -- Latham, David W -- Molinari, Emilio -- Udry, Stephane -- Bonomo, Aldo S -- Buchhave, Lars A -- Charbonneau, David -- Cosentino, Rosario -- Dressing, Courtney D -- Dumusque, Xavier -- Figueira, Pedro -- Fiorenzano, Aldo F M -- Gettel, Sara -- Harutyunyan, Avet -- Haywood, Raphaelle D -- Horne, Keith -- Lopez-Morales, Mercedes -- Lovis, Christophe -- Malavolta, Luca -- Mayor, Michel -- Micela, Giusi -- Motalebi, Fatemeh -- Nascimbeni, Valerio -- Phillips, David -- Piotto, Giampaolo -- Pollacco, Don -- Queloz, Didier -- Rice, Ken -- Sasselov, Dimitar -- Segransan, Damien -- Sozzetti, Alessandro -- Szentgyorgyi, Andrew -- Watson, Christopher A -- England -- Nature. 2013 Nov 21;503(7476):377-80. doi: 10.1038/nature12768. Epub 2013 Oct 30.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Observatoire Astronomique de l'Universite de Geneve, 51 chemin des Maillettes, 1290 Versoix, Switzerland.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/24172902" target="_blank"〉PubMed〈/a〉

Beschreibung: We present the discovery of three new transiting giant planets, first detected with the WASP telescopes, and establish their planetary nature with follow up spectroscopy and ground-based photometric light curves. WASP-92 is an F7 star, with a moderately inflated planet orbiting with a period of 2.17 d, which has R p  = 1.461 ± 0.077 R J and M p  = 0.805 ± 0.068 M J . WASP-93b orbits its F4 host star every 2.73 d and has R p  = 1.597 ± 0.077 R J and M p  = 1.47 ± 0.029 M J . WASP-118b also has a hot host star (F6) and is moderately inflated, where R p  = 1.440 ± 0.036 R J and M p  = 0.514 ± 0.020 M J and the planet has an orbital period of 4.05 d. They are bright targets ( V = 13.18, 10.97 and 11.07, respectively) ideal for further characterization work, particularly WASP-118b, which is being observed by K2 as part of campaign 8. The WASP-93 system has sufficient angular momentum to be tidally migrating outwards if the system is near spin–orbit alignment, which is divergent from the tidal behaviour of the majority of hot Jupiters discovered.

Beschreibung: A large observation programme was carried out to measure the radial velocities of the components of a selection of common proper motion (CPM) stars to select the physical binaries. 80 wide binaries (WBs) were detected, and 39 optical pairs were identified. By adding CPM stars with separations close enough to be almost certain that they are physical, a bias-controlled sample of 116 WBs was obtained, and used to derive the distribution of separations from 100 to 30 000 au. The distribution obtained does not match the log-constant distribution, but agrees with the log-normal distribution. The spectroscopic binaries detected among the WB components were used to derive statistical information about the multiple systems. The close binaries in WBs seem to be like those detected in other field stars. As for the WBs, they seem to obey the log-normal distribution of periods. The number of quadruple systems agrees with the no correlation hypothesis; this indicates that an environment conducive to the formation of WBs does not favour the formation of subsystems with periods shorter than 10 yr.