3,553 research outputs found

    A Uniformly Derived Catalogue of Exoplanets from Radial Velocities

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    A new catalogue of extrasolar planets is presented by re-analysing a selection of published radial velocity data sets using EXOFIT (Balan & Lahav 2009). All objects are treated on an equal footing within a Bayesian framework, to give orbital parameters for 94 exoplanetary systems. Model selection (between one- and two-planet solutions) is then performed, using both a visual flagging method and a standard chi-square analysis, with agreement between the two methods for 99% of the systems considered. The catalogue is to be made available online, and this 'proof of concept' study may be maintained and extended in the future to incorporate all systems with publicly available radial velocity data, as well as transit and microlensing data.Comment: 16 pages, 6 figures, 6 table

    ATPMN: accurate positions and flux densities at 5 and 8 GHz for 8,385 sources from the PMN survey

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    We present a source catalogue of 9,040 radio sources resulting from high-resolution observations of 8,385 PMN sources with the Australia Telescope Compact Array. The catalogue lists flux density and structural measurements at 4.8 and 8.6 GHz, derived from observations of all PMN sources in the declination range -87 deg < delta < -38.5 deg (exclusive of galactic latitudes |b| 70 mJy (50 mJy south of delta = -73 deg). We assess the quality of the data, which was gathered in 1992-1994, describe the population of catalogued sources, and compare it to samples from complementary catalogues. In particular we find 127 radio sources with probable association with gamma-ray sources observed by the orbiting Fermi Large Area Telescope.Comment: 20 pages, 21 figure

    Patient compliance with clinical follow-up after total joint arthroplasty

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    Patient compliance with clinical follow-up after total joint arthroplast

    Research Opportunities and Visions for Smart and Pervasive Health

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    Improving the health of the nation's population and increasing the capabilities of the US healthcare system to support diagnosis, treatment, and prevention of disease is a critical national and societal priority. In the past decade, tremendous advances in expanding computing capabilities--sensors, data analytics, networks, advanced imaging, and cyber-physical systems--have, and will continue to, enhance healthcare and health research, with resulting improvements in health and wellness. However, the cost and complexity of healthcare continues to rise alongside the impact of poor health on productivity and quality of life. What is lacking are transformative capabilities that address significant health and healthcare trends: the growing demands and costs of chronic disease, the greater responsibility placed on patients and informal caregivers, and the increasing complexity of health challenges in the US, including mental health, that are deeply rooted in a person's social and environmental context.Comment: A Computing Community Consortium (CCC) white paper, 12 page

    Mortality of Cranes (Gruidae) Associated with Powerlines over a Major Roost on the Platte River, Nebraska

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    Two 69-kilovolt powerlines spanning the Platte River in south central Nebraska are suspected to cause substantial mortality to sandhill cranes (Grus canadensis) and pose a threat to endangered whooping cranes (G. americana) that roost overnight on the river during spring and fall migrations. Most studies of crane collisions with powerlines in the region have focused on counts of carcasses away from night roosts on the river and none have accounted for potential biases in detecting carcasses. We found 61 carcasses of sandhill cranes below over-river segments of the two powerlines during 4 March to 7 April 2006 and 90 such carcasses between 5 March and 13 April 2007. In 2007 we estimated the number of carcasses undetected in our surveys due to removal by scavengers, loss to downstream flow, and observer oversight. We estimated between 165 and 219 sandhill cranes were killed by the two powerlines during spring 2007. These cnlculations exclude mortalities from individuals injured by powerline collisions and dying elsewhere, as well as those killed before or after our 5 March to 13 April survey period. We detected no evidence of mortality for whooping cranes during our surveys. Our results corroborate anecdotal evidence of signficant sandhill crane mortality each spring due to collisions with above-ground powerlines at this major night roost. Collisions by sandhill cranes will continue and collisions by Whooping cranes seem likely unless an effective means of averting birds from powerlines is implemented at this site

    An Eccentric Hot Jupiter Orbiting the Subgiant HD 185269

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    We report the detection of a Jupiter-mass planet in a 6.838 day orbit around the 1.28 solar mass subgiant HD 185269. The eccentricity of HD 185269b (e = 0.30) is unusually large compared to other planets within 0.1 AU of their stars. Photometric observations demonstrate that the star is constant to +/-0.0001 mag on the radial velocity period, strengthening our interpretation of a planetary companion. This planet was detected as part of our radial velocity survey of evolved stars located on the subgiant branch of the H-R diagram--also known as the Hertzsprung Gap. These stars, which have masses between 1.2 and 2.5 solar masses, play an important role in the investigation of the frequency of extrasolar planets as a function of stellar mass.Comment: 18 pages, 4 figures, 3 tables, ApJ in press (scheduled for Dec 2006, v652n2

    The California Planet Survey. I. Four New Giant Exoplanets

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    We present precise Doppler measurements of four stars obtained during the past decade at Keck Observatory by the California Planet Survey (CPS). These stars, namely, HD 34445, HD 126614, HD 13931, and Gl 179, all show evidence for a single planet in Keplerian motion. We also present Doppler measurements from the Hobby-Eberly Telescope (HET) for two of the stars, HD 34445 and Gl 179, that confirm the Keck detections and significantly refine the orbital parameters. These planets add to the statistical properties of giant planets orbiting near or beyond the ice line, and merit follow-up by astrometry, imaging, and space-borne spectroscopy. Their orbital parameters span wide ranges of planetary minimum mass (M sin i = 0.38-1.9 M(Jup)), orbital period (P = 2.87-11.5 yr), semimajor axis (a = 2.1-5.2 AU), and eccentricity (e = 0.02-0.41). HD 34445 b (P = 2.87 yr, M sin i = 0.79 MJup, e = 0.27) is a massive planet orbiting an old, G-type star. We announce a planet, HD 126614 Ab, and an M dwarf, HD 126614 B, orbiting the metal-rich star HD 126614 (which we now refer to as HD 126614 A). The planet, HD 126614 Ab, has minimum mass M sin i = 0.38 MJup and orbits the stellar primary with period P = 3.41 yr and orbital separation a = 2.3 AU. The faint M dwarf companion, HD 126614 B, is separated from the stellar primary by 489 mas (33 AU) and was discovered with direct observations using adaptive optics and the PHARO camera at Palomar Observatory. The stellar primary in this new system, HD 126614 A, has the highest measured metallicity ([ Fe/ H] = + 0.56) of any known planet-bearing star. HD 13931 b (P = 11.5 yr, M sin i = 1.88 MJup, e = 0.02) is a Jupiter analog orbiting a near solar twin. Gl 179 b (P = 6.3 yr, M sin i = 0.82 M(Jup), e = 0.21) is a massive planet orbiting a faint M dwarf. The high metallicity of Gl 179 is consistent with the planet-metallicity correlation among M dwarfs, as documented recently by Johnson & Apps.NSF AST-0702821NASA NNX06AH52GMcDonald Observator

    A Search for Multi-Planet Systems Using the Hobby-Eberly Telescope

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    Extrasolar multiple-planet systems provide valuable opportunities for testing theories of planet formation and evolution. The architectures of the known multiple-planet systems demonstrate a fascinating level of diversity, which motivates the search for additional examples of such systems in order to better constrain their formation and dynamical histories. Here we describe a comprehensive investigation of 22 planetary systems in an effort to answer three questions: 1) Are there additional planets? 2) Where could additional planets reside in stable orbits? and 3) What limits can these observations place on such objects? We find no evidence for additional bodies in any of these systems; indeed, these new data do not support three previously announced planets (HD 20367b: Udry et al. 2003, HD 74156d: Bean et al. 2008, and 47 UMa c: Fischer et al. 2002). The dynamical simulations show that nearly all of the 22 systems have large regions in which additional planets could exist in stable orbits. The detection-limit computations indicate that this study is sensitive to close-in Neptune-mass planets for most of the systems targeted. We conclude with a discussion on the implications of these non-detections.Comment: Accepted to ApJS. Includes 39 pages of radial-velocity data table
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