11,704 research outputs found
The IACOB project: A grid-based automatic tool for the quantitative spectroscopic analysis of O-stars
We present the IACOB grid-based automatic tool for the quantitative
spectroscopic analysis of O-stars. The tool consists of an extensive grid of
FASTWIND models, and a variety of programs implemented in IDL to handle the
observations, perform the automatic analysis, and visualize the results. The
tool provides a fast and objective way to determine the stellar parameters and
the associated uncertainties of large samples of O-type stars within a
reasonable computational time.Comment: 8 pages, 2 figures, 1 table. Proceedings of the "GREAT-ESF Stellar
Atmospheres in the Gaia Era Workshop
Single photo and electroproduction of pions at EBAC@JLAB
Within the Excited Baryon Analysis Center we have performed a dynamical
coupled-channels analysis of the available data in the region of
1.6 GeV and 1.45 (GeV/c). The channels included are
, , , and which has , , and components. With the hadronic parameters of the model
determined in our previous investigations of reaction, we have
found that the available data in the considered 1.6 GeV region can be
fitted well by only adjusting the bare helicity amplitudes
for the lowest states in , , and
partial waves. The meson cloud effect, as required by the unitarity conditions,
on the form factors are examined.Comment: 6 pages, invited talk at NSTAR 2009, Beijing (China), 2009, to appear
in the proceeding
Dynamics and stability of Bose-Einstein solitons in tilted optical lattices
Bloch oscillations of Bose-Einstein condensates realize sensitive matter-wave
interferometers. We investigate the dynamics and stability of bright-soliton
wave packets in one-dimensional tilted optical lattices with a modulated
mean-field interaction . By means of a time-reversal argument, we prove
the stability of Bloch oscillations of breathing solitons that would be
quasistatically unstable. Floquet theory shows that these breathing solitons
can be more stable against certain experimental perturbations than rigid
solitons or even non-interacting wave packets.Comment: final, published versio
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
Testing models with non-minimal Higgs sector through the decay t->q+WZ
We study the contribution of charged Higgs boson to the rare decay of the top
quark t->q+WZ (q=d,s,b) in models with Higgs sector that includes doublets and
triplets. Higgs doublets are needed to couple charged Higgs with quarks,
whereas the Higgs triplets are required to generate the non-standard vertex HWZ
at tree-level. It is found that within a model that respect the custodial SU(2)
symmetry and avoids flavour changing neutral currents by imposing discrete
symmetries, the decay mode t->b+WZ, can reach a branching ratio of order
0.0178, whereas the decay modes t->(d,s)+WZ, can reach a similar branching
ratio in models where flavour changing neutral currents are suppressed by
flavour symmetries.Comment: Typeset using REVTEX and EPSF, 5 pag, 2 figure
SOPHIE velocimetry of Kepler transit candidates VI. An additional companion in the KOI-13 system
We report the discovery of a new stellar companion in the KOI-13 system.
KOI-13 is composed by two fast-rotating A-type stars of similar magnitude. One
of these two stars hosts a transiting planet discovered by Kepler. We obtained
new radial velocity measurements using the SOPHIE spectrograph at the
Observatoire de Haute-Provence that revealed an additional companion in this
system. This companion has a mass between 0.4 and 1 Msun and orbits one of the
two main stars with a period of 65.831 \pm 0.029 days and an eccentricity of
0.52 \pm 0.02. The radial velocities of the two stars were derived using a
model of two fast-rotating line profiles. From the residuals, we found a hint
of the stellar variations seen in the Kepler light curve with an amplitude of
about 1.41 km/s and a period close to the rotational period. This signal
appears to be about three order of magnitude larger than expected for stellar
activity. From the analysis of the residuals, we also put a 3-sigma upper-limit
on the mass of the transiting planet KOI-13.01 of 14.8 Mjup and 9.4 Mjup,
depending on which star hosts the transit. We found that this new companion has
no significant impact on the photometric determination of the mass of KOI-13.01
but is expected to affect precise infrared photometry. Finally, using dynamical
simulations, we infer that the new companion is orbiting around KOI-13B while
the transiting planet candidate is expected to orbit KOI-13A. Thus, the
transiting planet candidate KOI-13.01 is orbiting the main component of a
hierarchical triple system.Comment: Accepted in A&A Letters. 4 pages including 4 figures and the RV tabl
Estudio palinológico del género Scorzonera L. (Asteraceace) en la Península Ibérica
Se estudian 72 poblaciones pertenecientes a 10 especies del género Scorzonera L. representadas en la Península Ibéri ca , tanto al microscopio óptico como al microscopio electrónico de barrido, poniéndose de manifiesto la variación cuant i tativa de ciertos parámetros escogidos , así como el polimor fismo morfológi co. Se confecciona una c l ave de determinación para las especies, atendiendo a sus caracteres polínicos72 popu lations of 10 species of genus Scorzoner a L. from the Iberian Peninsula , have been studied, both in light microscopy and in scanning electron microscopy . These resul ts demonstrate the quanti tati ve variation of' the· measurements se l ected as wel l as the morphologi cal polymorphism . A key using pollen characters has be en mad
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