2,351 research outputs found
TASTE IV. Refining ephemeris and orbital parameters for HAT-P-20b and WASP-1b
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
Variable stars in one open cluster within the Kepler/K2-Campaign-5 field: M 67 (NGC 2682)
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
TASTE. III. A homogeneous study of transit time variations in WASP-3b
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 Hubble Space Telescope UV Legacy Survey of Galactic Globular Clusters. XIII. ACS/WFC Parallel-Field Catalogues
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 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
arcmin from the cluster centre, thus covering a mean area of about
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
Topology-Induced Critical Current Enhancement in Josephson Networks
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
Investigation of current noise in underdamped Josephson devices by switching current measurements
AbstractExperimental measurements on critical current noise in underdamped niobium based Josephson devices by a technique based on the switching current measurements is reported. By sweeping the junction with a current ramp we measure the critical current switching as a function of the time using the standard time of flight technique. In such a way it is possible to obtain the critical current fluctuations ΔIc=Ic(t)-<Ic(t)> and the relative standard deviations which corresponds to the root square of the current fluctuation power. Pointing at the white noise fluctuations (above few Hz) and taking into account the physical frequency of the device, it is possible to evaluate the power spectral density of the critical current. The analysis has involved high quality underdamped Josephson junctions having an area ranging from (4x4) μm2 to (40x40) μm2 in the temperature range from 4.2K to few tenth of mK. These measurement provide very useful information about the intrinsic noise of Josephson devices involving SQUIDs and qubits
Atopy patch test are useful to predict oral tolerance in children with gastrointestinal symptoms related to non-IgE-mediated cow's milk allergy.
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 < 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
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