21,210 research outputs found
SOPHIE velocimetry of Kepler transit candidates IX. KOI-415 b: a long-period, eccentric transiting brown dwarf to an evolved Sun
We report the discovery of a long-period brown-dwarf transiting companion of
the solar-type star KOI-415. The transits were detected by the Kepler space
telescope. We conducted Doppler measurements using the SOPHIE spectrograph at
the Observatoire de Haute-Provence. The photometric and spectroscopic signals
allow us to characterize a 62.14+-2.69 Mjup, brown-dwarf companion of an
evolved 0.94+-0.06 Msun star in a highly eccentric orbit of P =
166.78805+-0.00022 days and e = 0.698+-0.002. The radius of KOI-415 b is 0.79
(-0.07,+0.12) Rjup, a value that is compatible with theoretical predictions for
a 10 Gyr, low-metallicity and non-irradiated object.Comment: accepted in A&A Letter
SOPHIE velocimetry of Kepler transit candidates XIV. A joint photometric, spectroscopic, and dynamical analysis of the Kepler-117 system
As part of our follow-up campaign of Kepler planets, we observed Kepler-117
with the SOPHIE spectrograph at the Observatoire de Haute-Provence. This
F8-type star hosts two transiting planets in non-resonant orbits. The planets,
Kepler-117 b and c, have orbital periods and days,
and show transit-timing variations (TTVs) of several minutes. We performed a
combined Markov chain Monte Carlo (MCMC) fit on transits, radial velocities,
and stellar parameters to constrain the characteristics of the system. We
included the fit of the TTVs in the MCMC by modeling them with dynamical
simulations. In this way, consistent posterior distributions were drawn for the
system parameters. According to our analysis, planets b and c have notably
different masses ( and M) and low
orbital eccentricities ( and ). The
uncertainties on the derived parameters are strongly reduced if the fit of the
TTVs is included in the combined MCMC. The TTVs allow measuring the mass of
planet b, although its radial velocity amplitude is poorly constrained.
Finally, we checked that the best solution is dynamically stable.Comment: 16 pages, of whom 5 of online material.12 figures, of whom 2 in the
online material. 7 tables, of whom 4 in the online material. Published in A&
Characterization of the four new transiting planets KOI-188b, KOI-195b, KOI-192b, and KOI-830b
The characterization of four new transiting extrasolar planets is presented
here. KOI-188b and KOI-195b are bloated hot Saturns, with orbital periods of
3.8 and 3.2 days, and masses of 0.25 and 0.34 M_Jup. They are located in the
low-mass range of known transiting, giant planets. KOI-192b has a similar mass
(0.29 M_Jup) but a longer orbital period of 10.3 days. This places it in a
domain where only a few planets are known. KOI-830b, finally, with a mass of
1.27 M_Jup and a period of 3.5 days, is a typical hot Jupiter. The four planets
have radii of 0.98, 1.09, 1.2, and 1.08 R_Jup, respectively. We detected no
significant eccentricity in any of the systems, while the accuracy of our data
does not rule out possible moderate eccentricities. The four objects were first
identified by the Kepler Team as promising candidates from the photometry of
the Kepler satellite. We establish here their planetary nature thanks to the
radial velocity follow-up we secured with the HARPS-N spectrograph at the
Telescopio Nazionale Galileo. The combined analyses of the datasets allow us to
fully characterize the four planetary systems. These new objects increase the
number of well-characterized exoplanets for statistics, and provide new targets
for individual follow-up studies. The pre-screening we performed with the
SOPHIE spectrograph at the Observatoire de Haute-Provence as part of that study
also allowed us to conclude that a fifth candidate, KOI-219.01, is not a planet
but is instead a false positive.Comment: 13 pages, 4 figures, 6 tables, final version accepted for publication
in A&
SOPHIE velocimetry of Kepler transit candidates XI. Kepler-412 system: probing the properties of a new inflated hot Jupiter
We confirm the planetary nature of Kepler-412b, listed as planet candidate
KOI-202 in the Kepler catalog, thanks to our radial velocity follow-up program
of Kepler-released planet candidates, which is on going with the SOPHIE
spectrograph. We performed a complete analysis of the system by combining the
Kepler observations from Q1 to Q15, to ground-based spectroscopic observations
that allowed us to derive radial velocity measurements, together with the host
star parameters and properties. We also analyzed the light curve to derive the
star's rotation period and the phase function of the planet, including the
secondary eclipse. We found the planet has a mass of 0.939 0.085
M and a radius of 1.325 0.043 R which makes it a member
of the bloated giant subgroup. It orbits its G3 V host star in 1.72 days. The
system has an isochronal age of 5.1 Gyr, consistent with its moderate stellar
activity as observed in the Kepler light curve and the rotation of the star of
17.2 1.6 days. From the detected secondary, we derived the day side
temperature as a function of the geometric albedo and estimated the geometrical
albedo, Ag, is in the range 0.094 to 0.013. The measured night side flux
corresponds to a night side brightness temperature of 2154 83 K, much
greater than what is expected for a planet with homogeneous heat
redistribution. From the comparison to star and planet evolution models, we
found that dissipation should operate in the deep interior of the planet. This
modeling also shows that despite its inflated radius, the planet presents a
noticeable amount of heavy elements, which accounts for a mass fraction of 0.11
0.04.Comment: 11 pages, 9 figure
Obesity and economic performance of young workers in Italy
In this paper we explore recent ISFOL-PLUS 2006-2008-2010 data available for Italy about height and weight of young workers with the purpose of analysing the relationship between measures of obesity and measures of economic performance. Among the latter, we introduce job satisfaction, both overall and for nine specific aspects, which has not been previously considered in the literature on the effects of obesity. Interestingly enough, we find that BMI does not discriminate young workers with respect to their job earnings, but it does affect negatively young workers' job satisfaction with important gender effects
Improved parameters of seven Kepler giant companions characterized with SOPHIE and HARPS-N
Radial-velocity observations of Kepler candidates obtained with the SOPHIE
and HARPS-N spectrographs have permitted unveiling the nature of the five giant
planets Kepler-41b, Kepler-43b, Kepler-44b, Kepler-74b, and Kepler-75b, the
massive companion Kepler-39b, and the brown dwarf KOI-205b. These companions
were previously characterized with long-cadence (LC) Kepler data. Here we aim
at refining the parameters of these transiting systems by i) modelling the
published radial velocities (RV) and Kepler short-cadence (SC) data that
provide a much better sampling of the transits, ii) performing new spectral
analyses of the SOPHIE and ESPaDOnS spectra, and iii) improving stellar
rotation periods hence stellar age estimates through gyrochronology, when
possible. Posterior distributions of the system parameters were derived with a
differential evolution Markov chain Monte Carlo approach. Our main results are
as follows: a) Kepler-41b is significantly larger and less dense than
previously found because a lower orbital inclination is favoured by SC data.
This also affects the determination of the geometric albedo that is lower than
previously derived: Ag < 0.135; b) Kepler-44b is moderately smaller and denser
than reported in the discovery paper; c) good agreement was achieved with
published Kepler-43, Kepler-75, and KOI-205 system parameters, although the
host stars Kepler-75 and KOI-205 were found to be slightly richer in metals and
hotter, respectively; d) the previously reported non-zero eccentricities of
Kepler-39b and Kepler-74b might be spurious. If their orbits were circular, the
two companions would be smaller and denser than in the eccentric case. The
radius of Kepler-39b is still larger than predicted by theoretical isochrones.
Its parent star is hotter and richer in metals than previously determined.
[ABRIDGED]Comment: 17 pages, 9 figures, accepted for publication in Astronomy and
Astrophysic
New broad 8Be nuclear resonances
Energies, total and partial widths, and reduced width amplitudes of 8Be
resonances up to an excitation energy of 26 MeV are extracted from a coupled
channel analysis of experimental data. The presence of an extremely broad J^pi
= 2^+ ``intruder'' resonance is confirmed, while a new 1^+ and very broad 4^+
resonance are discovered. A previously known 22 MeV 2^+ resonance is likely
resolved into two resonances. The experimental J^pi T = 3^(+)? resonance at 22
MeV is determined to be 3^-0, and the experimental 1^-? (at 19 MeV) and 4^-?
resonances to be isospin 0.Comment: 16 pages, LaTe
Probing the statistical decay and alpha-clustering effects in 12c+12c and 14n+10b reactions
An experimental campaign has been undertaken at INFN Laboratori Nazionali di
Legnaro, Italy, in order to progress in our understanding of the statistical
properties of light nuclei at excitation energies above particle emission
threshold, by measuring exclusive data from fusion-evaporation reactions. A
first reaction 12C+12C at 7.9 AMeV beam energy has been measured, using the
GARFIELD+Ring Counter experimental setup. Fusion-evaporation events have been
exclusively selected. The comparison to a dedicated Hauser-Feshbach calculation
allows us to give constraints on the nuclear level density at high excitation
energy for light systems ranging from C up to Mg. Out-of-equilibrium emission
has been evidenced and attributed both to entrance channel effects favoured by
the cluster nature of reaction partners and, in more dissipative events, to the
persistence of cluster correlations well above the 24Mg threshold for 6 alphas
decay. The 24Mg compound nucleus has been studied with a new measurement 14N +
10B at 5.7 AMeV. The comparison between the two datasets would allow us to
further constrain the level density of light nuclei. Deviations from a
statistical behaviour can be analyzed to get information on nuclear clustering.Comment: 4 pages, 2 figures, Contribution to conference proceedings of the
25th International Nuclear Physics Conference (INPC 2013
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