2,982 research outputs found

    TASTE IV. Refining ephemeris and orbital parameters for HAT-P-20b and WASP-1b

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    We present four new light curves of transiting exoplanets WASP-1b and HAT-P-20b, observed within the TASTE (The Asiago Search for Transit timing variations of Exoplanets) project. We re-analyzed light curves from the literature in a homogeneous way, calculating a refined ephemeris and orbital-physical parameters for both objects. WASP-1b does not show any significant Transit Timing Variation signal at the 120 s-level. As for HAT-P-20b, we detected a deviation from our re-estimated linear ephemeris that could be ascribed to the presence of a perturber or, more probably, to a previously unnoticed high level of stellar activity. The rotational period of HAT-P-20 A we obtained from archival data (P_rot ~ 14.5 days), combined with its optical variability and strong emission of CaII H&K lines, is consistent with a young stellar age (< 1 Gyr) and support the hypothesis that stellar activity may be responsible of the measured deviations of the transit times.Comment: 7 pages, 4 figures, 3 tables, accepted to Astronomische Nachrichte

    Study of the Quench Propagation and of the Protection System of the COS-theta NED Dipole Prototype

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    In this report we present our studies of the propagation of the quench in the NED dipole prototype, to derive a preliminary configuration of the protection system of the magnet (quench protection heaters, dump resistors, etc.). The simulations have been performed by using the code QLASA [1]. In this code, the geometry of the magnet is simplified to a series of solenoidal concentric magnets and the evolution of the quench is calculated with the Wilson's approach [2]. An analogous study has been performed with the CERN code QUABER [3],[4], and the results are discussed in section 3

    Variable stars in one open cluster within the Kepler/K2-Campaign-5 field: M 67 (NGC 2682)

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    In this paper we continue the release of high-level data products from the multiyear photometric survey collected at the 67/92 cm Schmidt Telescope in Asiago. The primary goal of the survey is to discover and to characterise variable objects and exoplanetary transits in four fields containing five nearby open clusters spanning a broad range of ages. This second paper releases a photometric catalogue, in five photometric bands, of the Solar-age, Solar-metallicity open cluster M 67 (NGC 2682). Proper motions are derived comparing the positions observed in 2013 at the Asiago's Schmidt Telescope with those extracted from [email protected] MPG/ESO images in 2000. We also analyse the variable sources within M 67. We detected 68 variables, 43 of which are new detection. Variable periods and proper-motion memberships of a large majority of sources in our catalogue are improved with respect to previous releases. The entire catalogue will be available in electronic format. Besides the general interest on an improved catalogue, this work will be particularly useful because of: (1) the imminent release of Kepler/K2 Campaign-5 data of this cluster, for which our catalogue will provide an excellent, high spatial resolution input list, and (2) characterisation of the M 67 stars which are targets of intense HARPS and HARPS-N radial-velocity surveys for planet search.Comment: 8 pages, 6 figures (2 at low resolution), 2 tables. Accepted for publication in MNRAS on October 17, 2015. Electronic materials available at the url http://groups.dfa.unipd.it/ESPG/M67.html , and later on the Journal and at the CD

    Topology-Induced Critical Current Enhancement in Josephson Networks

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    We investigate the properties of Josephson junction networks with inhomogeneous architecture. The networks are shaped as "quare comb" planar lattices on which Josephson junctions link superconducting islands arranged in the plane to generate the pertinent topology. Compared to the behavior of reference linear arrays, the temperature dependencies of the Josephson currents of the branches of the network exhibit relevant differences. The observed phenomena evidence new and surprising behavior of superconducting Josephson arrays as well as remarkable similarities with bosonic junction arrays.Comment: improved figures (added magnetic pattern and single junction switching) some changes in the text and in the titl

    TASTE. III. A homogeneous study of transit time variations in WASP-3b

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    The TASTE project is searching for low-mass planets with the Transit Timing Variation (TTV) technique, by gathering high-precision, short-cadence light curves for a selected sample of transiting exoplanets. It has been claimed that the "hot Jupiter" WASP-3b could be perturbed by a second planet. Presenting eleven new light curves (secured at the IAC80 and UDEM telescopes) and re-analyzing thirty-eight archival light curves in a homogeneous way, we show that new data do not confirm the previously claimed TTV signal. However, we bring evidence that measurements are not consistent with a constant orbital period, though no significant periodicity can be detected. Additional dynamical modeling and follow-up observations are planned to constrain the properties of the perturber or to put upper limits to it. We provide a refined ephemeris for WASP-3b and improved orbital/physical parameters. A contact eclipsing binary, serendipitously discovered among field stars, is reported here for the first time.Comment: 10 pages, 6 figures, 4 tables; accepted for publication in A&

    The supernova impostor PSN J09132750+7627410 and its progenitor

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    We report the results of our follow-up campaign of the supernova impostor PSN J09132750+7627410, based on optical data covering 250d\sim250\,\rm{d}. From the beginning, the transient shows prominent narrow Balmer lines with P-Cygni profiles, with a blue-shifted absorption component becoming more prominent with time. Along the 3months\sim3\,\rm{months} of the spectroscopic monitoring, broad components are never detected in the hydrogen lines, suggesting that these features are produced in slowly expanding material. The transient reaches an absolute magnitude Mr=13.60±0.19magM_r=-13.60\pm0.19\,\rm{mag} at maximum, a typical luminosity for supernova impostors. Amateur astronomers provided 4years\sim4\,\rm{years} of archival observations of the host galaxy, NGC 2748. The detection of the quiescent progenitor star in archival images obtained with the Hubble Space Telescope suggests it to be an 182018-20\msun white-yellow supergiant.Comment: 7 pages, 4 figures, supplemental material available in the source file. Accepted for publication on Astrophysical Journal Letter

    Atopy patch test are useful to predict oral tolerance in children with gastrointestinal symptoms related to non-IgE-mediated cow's milk allergy.

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    Atopy patch tests (APTs) have been proposed for the diagnostic approach in children with non-IgE-mediated cow's milk allergy and gastrointestinal symptoms. We aimed to investigate the benefit of APTs in predicting oral tolerance in these patients. We prospectively evaluated 172 subjects with a sure diagnosis of non-IgE-mediated CMA and gastrointestinal symptoms (97 boys, 56.4%; age, 6.37 m; range, 212 m). At diagnosis, 113/172 (65.7%) children had positive APTs to cow's milk proteins (CMP). After 12 months of exclusion, diet APTs were repeated immediately before OFC. APTs significantly correlated (P &lt; 0.001) with the OFC outcome (r 0.579). Diagnostic accuracy was sensitivity of 67.95%, specificity of 88.3%, PPV of 82.81%, NPV of 76.85%, and a +LR of 5.80. APTs are a valuable tool in the follow-up of children with non-IgE-mediated CMA-related gastrointestinal symptoms by contributing in determining whether an OFC can safely be undertaken

    The Hubble Space Telescope UV Legacy Survey of Galactic Globular Clusters. XIII. ACS/WFC Parallel-Field Catalogues

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    As part of the Hubble Space Telescope UV Legacy Survey of Galactic Globular Clusters, 110 parallel fields were observed with the Wide Field Channel of the Advanced Camera for Surveys, in the outskirts of 48 globular clusters, plus the open cluster NGC 6791. Totalling about 0.30.3 square degrees of observed sky, this is the largest homogeneous Hubble Space Telescope photometric survey of Galalctic globular clusters outskirts to date. In particular, two distinct pointings have been obtained for each target on average, all centred at about 6.56.5 arcmin from the cluster centre, thus covering a mean area of about 23arcmin223\,{\rm arcmin^{2}} for each globular cluster. For each field, at least one exposure in both F475W and F814W filters was collected. In this work, we publicly release the astrometric and photometric catalogues and the astrometrised atlases for each of these fields.Comment: 30 pages, 23 figures. Accepted by MNRA
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