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Aims: In recent years several in-depth investigations of the three prototypical Of?p stars were undertaken. These multiwavelength studies revealed the peculiar properties of these objects (in the X ... [more ▼]
Aims: In recent years several in-depth investigations of the three prototypical Of?p stars were undertaken. These multiwavelength studies revealed the peculiar properties of these objects (in the X-rays as well as in the optical): magnetic fields, periodic line profile variations, recurrent photometric changes. However, many questions remain unsolved.
Methods: To clarify some of the properties of the Of?p stars, we have continued their monitoring. A new xmm-Newton observation and two new optical datasets were obtained.
Results: Additional information about the prototypical Of?p trio has been found. HD 108 has now reached its quiescent, minimum-emission state for the first time in 50-60 yr. The Ã©chelle spectra of HD 148937 confirm the presence of the 7d variations in the Balmer lines and reveal similar periodic variations (though of lower amplitudes) in the He i Î» 5876 and He ii Î» 4686 lines, underlining its similarities with the other two prototypical Of?p stars. The new xmm-Newton observation of HD 191612 was taken at the same phase in the line modulation cycle, but at a different orbital phase from previous data. It clearly shows that the X-ray emission of HD 191612 is modulated by the 538d period and not by the orbital period of 1542d - it is thus not of colliding-wind origin. The phenomenon responsible for the optical changes appears also at work in the high-energy domain. There are problems however: our MHD simulations of the wind magnetic confinement predict both a harder X-ray flux of a much larger strength than what is observed (the modelled differential emission measure peaks at 30-40 MK, whereas the observed one peaks at 2 MK) and narrow lines (hot gas moving with velocities of 100-200 km s[SUP]-1[/SUP], whereas the observed full width at half maximum is ~2000 km s[SUP]-1[/SUP]). Based on observations collected at the Haute-Provence Observatory, at the La Silla and San Pedro MÃ¡rtir Observatories, and with XMM-Newton, an ESA Science Mission with instruments and contributions directly funded by ESA Member States and the USA (NASA). [less ▲]Detailed reference viewed: 27 (5 ULiège) Transiting exoplanets from the CoRoT space mission. XII. CoRoT-12b: a short-period low-density planet transiting a solar analog starGillon, Michaël ; Hatzes, A.; Csizmadia, Szilard et alin Astronomy and Astrophysics (2010), 520We report the discovery by the CoRoT satellite of a new transiting giant planet in a 2.83 days orbit about a V = 15.5 solar analog star (M_* = 1.08 ± 0.08 M_ȯ, R_* = 1.1 ± 0.1 R_ȯ, T[SUB]eff[/SUB] = 5675 ... [more ▼]We report the discovery by the CoRoT satellite of a new transiting giant planet in a 2.83 days orbit about a V = 15.5 solar analog star (M_* = 1.08 ± 0.08 M_ȯ, R_* = 1.1 ± 0.1 R_ȯ, T[SUB]eff[/SUB] = 5675 ± 80 K). This new planet, CoRoT-12b, has a mass of 0.92 ± 0.07 M[SUB]Jup[/SUB] and a radius of 1.44 ± 0.13 R[SUB]Jup[/SUB]. Its low density can be explained by standard models for irradiated planets. The CoRoT space mission, launched on December 27, 2006, has been developed and is operated by CNES, with the contribution of Austria, Belgium, Brazil, ESA (RSSD and Science Program), Germany and Spain. [less ▲]Detailed reference viewed: 48 (5 ULiège) WASP-24 b: A New Transiting Close-in Hot Jupiter Orbiting a Late F-starStreet, R. A.; Simpson, E.; Barros, S. C. C. et alin Astrophysical Journal (2010), 720We report the discovery of a new transiting close-in giant planet, WASP-24 b, in a 2.341 day orbit, 0.037 AU from its F8-9 type host star. By matching the star's spectrum with theoretical models, we infer ... [more ▼]We report the discovery of a new transiting close-in giant planet, WASP-24 b, in a 2.341 day orbit, 0.037 AU from its F8-9 type host star. By matching the star's spectrum with theoretical models, we infer an effective temperature T [SUB]eff[/SUB] = 6075 ± 100 K and a surface gravity of log g = 4.15 ± 0.10. A comparison of these parameters with theoretical isochrones and evolutionary mass tracks places only weak constraints on the age of the host star, which we estimate to be 3.8[SUP]+1.3[/SUP] [SUB]-1.2[/SUB] Gyr. The planetary nature of the companion was confirmed by radial velocity measurements and additional photometric observations. These data were fit simultaneously in order to determine the most probable parameter set for the system, from which we infer a planetary mass of 1.071[SUP]+0.036[/SUP] [SUB]-0.038[/SUB] M [SUB]Jup[/SUB] and radius 1.3[SUP]+0.039[/SUP] [SUB]-0.037[/SUB] R [SUB]Jup[/SUB]. [less ▲]Detailed reference viewed: 22 (0 ULiège) Transiting exoplanets from the CoRoT space mission. XI. CoRoT-8b: a hot and dense sub-Saturn around a K1 dwarfBordé, P.; Bouchy, F.; Deleuil, M. et alin Astronomy and Astrophysics (2010), 520
Aims: We report the discovery of CoRoT-8b, a dense small Saturn-class exoplanet that orbits a K1 dwarf in 6.2 days, and we derive its orbital parameters, mass, and radius.
Methods: We ... [more ▼]
Aims: We report the discovery of CoRoT-8b, a dense small Saturn-class exoplanet that orbits a K1 dwarf in 6.2 days, and we derive its orbital parameters, mass, and radius.
Methods: We analyzed two complementary data sets: the photometric transit curve of CoRoT-8b as measured by CoRoT and the radial velocity curve of CoRoT-8 as measured by the HARPS spectrometer.
Results: We find that CoRoT-8b is on a circular orbit with a semi-major axis of 0.063 ± 0.001 AU. It has a radius of 0.57 ± 0.02 R[SUB]J[/SUB], a mass of 0.22 ± 0.03 M[SUB]J[/SUB], and therefore a mean density of 1.6 ± 0.1 g cm[SUP]-3[/SUP].
Conclusions: With 67% of the size of Saturn and 72% of its mass, CoRoT-8b has a density comparable to that of Neptune (1.76 g cm[SUP]-3[/SUP]). We estimate its content in heavy elements to be 47-63 {M}_⊕, and the mass of its hydrogen-helium envelope to be 7-23 {M}_⊕. At 0.063 AU, the thermal loss of hydrogen of CoRoT-8b should be no more than 0.1% over an assumed integrated lifetime of 3 Ga. Observations made with SOPHIE spectrograph at Observatoire de Haute Provence, France (PNP.07B.MOUT), and the HARPS spectrograph at ESO La Silla Observatory (081.C-0388 and 083.C-0186). The CoRoT space mission, launched on December 27, 2006, has been developed and is operated by the CNES with the contribution of Austria, Belgium, Brasil, ESA, Germany, and Spain.Both data sets are available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/520/A66 [less ▲]Detailed reference viewed: 32 (2 ULiège) Transiting exoplanets from the CoRoT space mission. X. CoRoT-10b: a giant planet in a 13.24 day eccentric orbitBonomo, A. S.; Santerne, A.; Alonso, R. et alin Astronomy and Astrophysics (2010), 520Context. The space telescope CoRoT searches for transiting extrasolar planets by continuously monitoring the optical flux of thousands of stars in several fields of view.
Aims: We report the ... [more ▼]Context. The space telescope CoRoT searches for transiting extrasolar planets by continuously monitoring the optical flux of thousands of stars in several fields of view.
Aims: We report the discovery of CoRoT-10b, a giant planet on a highly eccentric orbit (e = 0.53 ± 0.04) revolving in 13.24 days around a faint (V = 15.22) metal-rich K1V star.
Methods: We used CoRoT photometry, radial velocity observations taken with the HARPS spectrograph, and UVES spectra of the parent star to derive the orbital, stellar, and planetary parameters.
Results: We derive a radius of the planet of 0.97 ± 0.07 R[SUB]Jup[/SUB] and a mass of 2.75 ± 0.16 M[SUB]Jup[/SUB]. The bulk density, ρ[SUB]p[/SUB] = 3.70 ± 0.83 g cm[SUP]-3[/SUP], is ~2.8 that of Jupiter. The core of CoRoT-10b could contain up to 240 M_⊕ of heavy elements. Moving along its eccentric orbit, the planet experiences a 10.6-fold variation in insolation. Owing to the long circularisation time, τ[SUB]circ[/SUB] > 7 Gyr, a resonant perturber is not required to excite and maintain the high eccentricity of CoRoT-10b. The CoRoT space mission, launched on December 27th 2006, has been developed and is operated by CNES, with the contribution of Austria, Belgium, Brazil, ESA (RSSD and Science Programme), Germany and Spain. [less ▲]Detailed reference viewed: 38 (0 ULiège) Quelle cible tensionnelle idéale pour nos patients hypertendus en 2010?Krzesinski, Jean-Marie ; Saint-Remy, Annie in Revue Médicale Suisse (2010), 6Les directives du traitement de l'hypertension artérielle de 2007 ont été rediscutées en 2009. Quelle que soit la pathologie associée à l'hypertension artérielle, la cible à atteindre est : 130 à 139 mmHg ... [more ▼]Les directives du traitement de l'hypertension artérielle de 2007 ont été rediscutées en 2009. Quelle que soit la pathologie associée à l'hypertension artérielle, la cible à atteindre est : 130 à 139 mmHg pour la systolique et 80 à 85 mmHg pour la diastolique. Si le patient peut tolérer une pression plus basse, on ne freinera pas l’abaissement de pression. Beaucoup de questions restent cependant encore sans réelles réponses quant à des cibles plus basses en fonction de l’âge et de situations pathologiques individuelles. Le choix des agents antihypertenseurs devient primordial lors d’un risque cardiovasculaire majeur. Il convient toujours d’appliquer des règles hygiéno-diététiques à l’ensemble de la population hypertendue et d’agir sur tous les facteurs de risque associés. [less ▲]Detailed reference viewed: 63 (0 ULiège) Frequency of Solar-like Systems and of Ice and Gas Giants Beyond the Snow Line from High-magnification Microlensing Events in 2005-2008Gould, A.; Dong, Subo; Gaudi, B. S. et alin Astrophysical Journal (2010), 720We present the first measurement of the planet frequency beyond the "snow line," for the planet-to-star mass-ratio interval –4.5 < log q < –2, corresponding to the range of ice giants to gas giants. We ... [more ▼]We present the first measurement of the planet frequency beyond the "snow line," for the planet-to-star mass-ratio interval –4.5 < log q < –2, corresponding to the range of ice giants to gas giants. We find \endgraf\vbox{\begin{center}$\displaystyle{d^2 N{_{\rm pl}}\over d\log q\, d\log s} = (0.36\pm 0.15)\;{\rm dex}^{-2}$\end{center}}\noindentat the mean mass ratio q = 5 × 10 –4 with no discernible deviation from a flat (Öpik's law) distribution in log-projected separation s. The determination is based on a sample of six planets detected from intensive follow-up observations of high-magnification ( A>200) microlensing events during 2005-2008. The sampled host stars have a typical mass M host ~ 0.5 M sun [less ▲]Detailed reference viewed: 129 (13 ULiège)