Browsing
     by title


0-9 A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

or enter first few letters:   
OK
See detailHot dust in the inner parts of circumstellar debris discs
Absil, Olivier ULiege

Scientific conference (2009, April 01)

Studying the warm inner part of debris discs—the extrasolar counterparts of the zodiacal dust cloud—is of prime importance to characterize the global architecture of planetary systems. Because of the high ... [more ▼]

Studying the warm inner part of debris discs—the extrasolar counterparts of the zodiacal dust cloud—is of prime importance to characterize the global architecture of planetary systems. Because of the high contrast and small angular separation between the star and the exozodiacal light, high-precision infrared interferometry is the best-suited tool to carry out such observations. In this paper, we review the first direct detection of an exozodiacal disc recently reported around Vega by Absil et al. (2006), and discuss the currently on-going observing efforts in this domain. We show how interferometric data can constrain the composition and the dynamics of extrasolar planetary systems, and thereby put useful constraints on the presence of small bodies and/or giant planets. First statistical trends for high-density exozodiacal discs towards a small sample of nearby main sequence stars are presented. Finally, we briefly discuss how next generation interferometric instruments could change our view of debris discs, pushing the detection limit towards meaningful density levels in the context of future life-finding missions such as Darwin/TPF. [less ▲]

Detailed reference viewed: 7 (1 ULiège)
Full Text
Peer Reviewed
See detailHot electron production and diffuse excited states in C70, C82, and Sc3N@C80 characterized by angular-resolved photoelectron spectroscopy
Johansson, J. Olof; Bohl, Elvira; Henderson, Gordon G. et al

in Journal of Chemical Physics (2013), 139

Detailed reference viewed: 15 (2 ULiège)
Full Text
Peer Reviewed
See detailHot exozodiacal dust resolved around Vega with IOTA/IONIC
Defrere, Denis ULiege; Absil, Olivier ULiege; Augereau, J.-C. et al

in Astronomy and Astrophysics (2011), 534

Context. Although debris discs have been detected around a significant number of main-sequence stars, only a few of them are known to harbour hot dust in their inner part where terrestrial planets may ... [more ▼]

Context. Although debris discs have been detected around a significant number of main-sequence stars, only a few of them are known to harbour hot dust in their inner part where terrestrial planets may have formed. Thanks to infrared interferometric observations, it is possible to obtain a direct measurement of these regions, which are of prime importance for preparing future exo-Earth characterisation missions. <BR /> Aims: We resolve the exozodiacal dust disc around Vega with the help of infrared stellar interferometry and estimate the integrated H-band flux originating from the first few AUs of the debris disc. <BR /> Methods: Precise H-band interferometric measurements were obtained on Vega with the 3-telescope IOTA/IONIC interferometer (Mount Hopkins, Arizona). Thorough modelling of both interferometric data (squared visibility and closure phase) and spectral energy distribution was performed to constrain the nature of the near-infrared excess emission. <BR /> Results: Resolved circumstellar emission within ~6 AU from Vega is identified at the 3-σ level. The most straightforward scenario consists in a compact dust disc producing a thermal emission that is largely dominated by small grains located between 0.1 and 0.3 AU from Vega and accounting for 1.23 ± 0.45% of the near-infrared stellar flux for our best-fit model. This flux ratio is shown to vary slightly with the geometry of the model used to fit our interferometric data (variations within ± 0.19%). <BR /> Conclusions: The presence of hot exozodiacal dust in the vicinity of Vega, initially revealed by K-band CHARA/FLUOR observations, is confirmed by our H-band IOTA/IONIC measurements. Whereas the origin of the dust is still uncertain, its presence and the possible connection with the outer disc suggest that the Vega system is currently undergoing major dynamical perturbations. [less ▲]

Detailed reference viewed: 50 (1 ULiège)
Full Text
See detailHot gas distribution in the wind of ζ Pup and ζ Ori
Herve, A.; Rauw, Grégor ULiege; Nazé, Yaël ULiege

Poster (2013, June 01)

We have developped a new X-ray modelling code based on embedded shocks which computes synthetic spectra as a function of plasma temperature, abundances and localization of the X-ray emitting shell in the ... [more ▼]

We have developped a new X-ray modelling code based on embedded shocks which computes synthetic spectra as a function of plasma temperature, abundances and localization of the X-ray emitting shell in the wind. We have also included a proper treatment of the radial dependence of the X-ray opacity of the cool matter as well as a treatment forthe Forbiden Inter combination Resonance (FIR) lines of He-like ions. Our code combines several synthetic spectra in order to fit all the lines of an X-ray spectrum simultaneously and coherently. Our results on two O-type stars ζ Pup and ζ Ori reveal non-porous winds with a mass loss rate consistent with studies in the optical domain as well as non-solar abundances for the CNO elements as expected for evolved stars. More important, the X-ray plasma starts emitting close to the stellarsurface. An improved version of our code allowing an analysis of the radial dependence of the hot gas filling factor reveals for ζ Ori a non continuity of the X-ray emission regions associated to high values of the hot gas filling factor. [less ▲]

Detailed reference viewed: 18 (1 ULiège)
See detailThe hot Jupiter WASP-­121 b: A planet heading towards its doom
Delrez, Laetitia ULiege

Conference (2015, May 28)

We present here the discovery by the WASP-South survey, in close collaboration with the Euler and TRAPPIST telescopes, of WASP-121 b, a new remarkable short-period transiting hot Jupiter. WASP-121 b is a ... [more ▼]

We present here the discovery by the WASP-South survey, in close collaboration with the Euler and TRAPPIST telescopes, of WASP-121 b, a new remarkable short-period transiting hot Jupiter. WASP-121 b is a very inflated (1.86 Rjup) Jupiter-mass (1.18 Mjup) planet that transits every 1.27 days a bright active F6V star. A notable property of WASP-121b is that its orbital semi-major axis is only 15% larger than its Roche limit, which suggests that the planet might be close to tidal disruption. Furthermore, its large size and extreme irradiation (7.1 10^9 erg s^-1 cm^-2) make it an excellent target for atmospheric studies via secondary eclipse observations. Using the TRAPPIST robotic telescope, we indeed detect its thermal emission in the z’-band at better than ~4sigma, the measured occultation depth being 603+-130 ppm. This measurement is a first for a ground-based 60cm telescope. Finally, from a measurement of the Rossiter-McLaughlin effect with the CORALIE spectrograph, we infer a sky-projected spin-orbit angle of 257.8+-6 deg. This result indicates a significant misalignment between the spin axis of the host star and the orbital plane of the planet, the planet being in a nearly polar orbit. [less ▲]

Detailed reference viewed: 48 (7 ULiège)
Full Text
Peer Reviewed
See detailHot Jupiters with relatives: discovery of additional planets in orbit around WASP-41 and WASP-47
Neveu-VanMalle, M.; Queloz, D.; Anderson, D. R. et al

in Astronomy and Astrophysics (2016), 586

We report the discovery of two additional planetary companions to WASP-41 and WASP-47. WASP-41 c is a planet of minimum mass 3.18 $\pm$ 0.20 M$_{\rm Jup}$ and eccentricity 0.29 $\pm$ 0.02, and it orbits ... [more ▼]

We report the discovery of two additional planetary companions to WASP-41 and WASP-47. WASP-41 c is a planet of minimum mass 3.18 $\pm$ 0.20 M$_{\rm Jup}$ and eccentricity 0.29 $\pm$ 0.02, and it orbits in 421 $\pm$ 2 days. WASP-47 c is a planet of minimum mass 1.24 $\pm$ 0.22 M$_{\rm Jup}$ and eccentricity 0.13 $\pm$ 0.10, and it orbits in 572 $\pm$ 7 days. Unlike most of the planetary systems that include a hot Jupiter, these two systems with a hot Jupiter have a long-period planet located at only $\sim$1 au from their host star. WASP-41 is a rather young star known to be chromospherically active. To differentiate its magnetic cycle from the radial velocity effect induced by the second planet, we used the emission in the H$\alpha$ line and find this indicator well suited to detecting the stellar activity pattern and the magnetic cycle. The analysis of the Rossiter-McLaughlin effect induced by WASP-41 b suggests that the planet could be misaligned, though an aligned orbit cannot be excluded. WASP-47 has recently been found to host two additional transiting super Earths. With such an unprecedented architecture, the WASP-47 system will be very important for understanding planetary migration. [less ▲]

Detailed reference viewed: 69 (4 ULiège)
Full Text
Peer Reviewed
See detailHot Melt Extrusion as a New Method to Form Inclusion Complexes with Cyclodextrins
Thiry, Justine ULiege; Krier, Fabrice; Ratwatte, Shenelka et al

Conference (2016, April 06)

Detailed reference viewed: 36 (4 ULiège)
Full Text
Peer Reviewed
See detailHot Nuclear Matter in an Extended Brueckner Approach
Cugnon, Joseph ULiege; Lejeune, André ULiege; Grangé, pierre et al

in Nuclear Physics A (1986), 453

Detailed reference viewed: 17 (5 ULiège)
Full Text
Peer Reviewed
See detailHot Nuclei in Reactions Induced by 475 MeV, 2 GeV 1H and 2 GeV 3He
Cugnon, Joseph ULiege; Pienkowski, L.; Bohlen, H. G. et al

in Physics Letters B (1994), 336

Detailed reference viewed: 10 (1 ULiège)
See detailThe Hot Oxygen Corona of Mars: Observations by MAVEN IUVS
Deighan; IUVS team; Stiepen, Arnaud ULiege

Poster (2015, December)

Detailed reference viewed: 22 (2 ULiège)
Full Text
See detailHot shortness and scaling of Copper containing steels
Habraken, Louis; Lecomte-Beckers, Jacqueline ULiege

in Le May, I.; Mc. Schetky, L. (Eds.) Copper in Iron and Steel (1982)

Detailed reference viewed: 93 (4 ULiège)
Full Text
See detailHot stars in the whole CoRoT mission
Briquet, Maryline ULiege

Conference (2013, March 20)

Detailed reference viewed: 35 (5 ULiège)
Full Text
Peer Reviewed
See detailHot stars observed by XMM-Newton. I. The catalog and the properties of OB stars
Nazé, Yaël ULiege

in Astronomy and Astrophysics (2009), 506

Aims: Following the advent of increasingly sensitive X-ray observatories, deep observations of early-type stars became possible. However, the results for only a few objects or clusters have until now been ... [more ▼]

Aims: Following the advent of increasingly sensitive X-ray observatories, deep observations of early-type stars became possible. However, the results for only a few objects or clusters have until now been reported and there has been no large survey comparable to that based upon the ROSAT All-Sky Survey (RASS). <BR />Methods: A limited survey of X-ray sources, consisting of all public XMM-Newton observations (2XMMi) and slew survey data (XMMSL1), is now available. The X-ray counterparts to hot, massive stars have been searched for in these catalogs. <BR />Results: About 300 OB stars were detected with XMM-Newton. Half of them were bright enough for a spectral analysis to be possible, and we make available the detailed spectral properties that were derived. The X-ray spectra of O stars are represented well by low (<1 keV) temperature components and seem to indicate that an absorption column is present in addition to the interstellar contribution. The X-ray fluxes are well correlated with the bolometric fluxes, with a scatter comparable to that of the RASS studies and thus larger than found previously with XMM-Newton for some individual clusters. These results contrast with those of B stars that exhibit a large scatter in the L[SUB]X[/SUB] - L[SUB]BOL[/SUB] relation, no additional absorption being found, and the fits indicate a plasma at higher temperatures. Variability (either within one exposure or between multiple exposures) was also investigated whenever possible: short-term variations are far more rare than long-term ones (the former affects a few percent of the sample, while the latter concerns between one third and two thirds of the sources). <BR />Conclusions: This paper presents the results of the first high-sensitivity investigation of the overall high-energy properties of a sizable sample of hot stars. Based on observations collected with XMM-Newton, an ESA Science Mission with instruments and contributions directly funded by ESA Member States and the USA (NASA), and accessed via the 2XMMi and XMM slew survey catalogs. Tables 1 and 5 are only available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/506/1055 Postdoctoral Researcher FNRS. Visiting astronomer, UNAM-Morelos (Mexico). [less ▲]

Detailed reference viewed: 48 (4 ULiège)
See detailHot stars survey with the GAIA space mission
Lobel, A.; Liu, C.; Frémat, Y. et al

Poster (2009)

Detailed reference viewed: 33 (11 ULiège)
See detailHot Topic : Clinical and genetics features of familial isolated pituitary adenomas
Beckers, Albert ULiege

Scientific conference (2006, October)

Detailed reference viewed: 11 (1 ULiège)
Full Text
Peer Reviewed
See detailHot topic: Innovative lactation-stage-dependent prediction of methane emissions from milk mid-infrared spectra
Vanlierde, Amélie; Vanrobays, Marie-Laure ULiege; Dehareng, Frédéric et al

in Journal of Dairy Science (2015), In press

Detailed reference viewed: 137 (55 ULiège)
Full Text
Peer Reviewed
See detailA hot Uranus transiting the nearby M dwarf GJ 3470. Detected with HARPS velocimetry. Captured in transit with TRAPPIST photometry
Bonfils, X.; Gillon, Michaël ULiege; Udry, S. et al

in Astronomy and Astrophysics (2012), 546

We report on the discovery of GJ 3470 b, a transiting hot Uranus of mass m[SUB]p[/SUB] = 14.0 ± 1.8 M[SUB]⊕[/SUB], radius R[SUB]p[/SUB] = 4.2 ± 0.6 R[SUB]⊕[/SUB] and period P = 3.3371 ± 0.0002 day. Its ... [more ▼]

We report on the discovery of GJ 3470 b, a transiting hot Uranus of mass m[SUB]p[/SUB] = 14.0 ± 1.8 M[SUB]⊕[/SUB], radius R[SUB]p[/SUB] = 4.2 ± 0.6 R[SUB]⊕[/SUB] and period P = 3.3371 ± 0.0002 day. Its host star is a nearby (d = 25.2 ± 2.9 pc) M1.5 dwarf of mass M[SUB]⋆[/SUB] = 0.54 ± 0.07 M[SUB]&sun;[/SUB] and radius R[SUB]⋆[/SUB] = 0.50 ± 0.06 R[SUB]&sun;[/SUB]. The detection was made during a radial-velocity campaign with Harps that focused on the search for short-period planets orbiting M dwarfs. Once the planet was discovered and the transit-search window narrowed to about 10% of an orbital period, a photometric search started with Trappist and quickly detected the ingress of the planet. Additional observations with Trappist, EulerCam and Nites definitely confirmed the transiting nature of GJ 3470b and allowed the determination of its true mass and radius. The star's visible or infrared brightness (V[SUP]mag[/SUP] = 12.3, K[SUP]mag[/SUP] = 8.0), together with a large eclipse depth D = 0.57 ± 0.05%, ranks GJ 3470 b among the most suitable planets for follow-up characterizations. Based on observations made with the HARPS instrument on the ESO 3.6 m telescope under the program IDs 183.C-0437 at Cerro La Silla (Chile).Our radial-velocity and photometric time series are only available at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via <A href="http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/546/A27">http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/546/A27</A> [less ▲]

Detailed reference viewed: 32 (1 ULiège)
Full Text
Peer Reviewed
See detailHot water tanks : how to select the optimal modelling approach?
Dumont, Olivier ULiege; Carmo, Carolina; Dickes, Rémi ULiege et al

Conference (2016)

Detailed reference viewed: 47 (8 ULiège)
See detailHot-cold plasma interactions and the generation of transient dayside sub-auroral proton precipitation
Fuselier, S. A.; Gary, S. P.; Thomsen, M. F. et al

Conference (2003, December 01)

The IMAGE spacecraft obtained the first global images of the proton aurora. One of the discoveries from these images was proton precipitation equatorward of the nominal auroral oval. This precipitation ... [more ▼]

The IMAGE spacecraft obtained the first global images of the proton aurora. One of the discoveries from these images was proton precipitation equatorward of the nominal auroral oval. This precipitation can be observed for approximately 10 minutes immediately following a large solar wind pressure pulse. Various mechanisms have been proposed for producing this precipitation. Here, precipitation due to scattering from electromagnetic ion cyclotron (EMIC) waves is investigated using data from the IMAGE FUV and EUV imagers and in situ data from the Los Alamos geosynchronous spacecraft. In the proposed EMIC wave mechanism, the compression of the dayside magnetosphere enhances the growth rate of the wave instability. These waves scatter hot, ring current protons into the atmospheric loss cone, reducing the proton temperature anisotropy (the free energy source of the waves). Two features of the proton precipitation from these waves require explanation. First, the precipitation pattern may peak at any local time on the dayside between about 09 and 15. Second, the precipitation pattern has limited latitudinal extent (typically less than about 10 degrees) and is often separated from the main auroral oval. The local time peak in the precipitation pattern is related to the characteristics of the solar wind pressure pulse that causes EMIC wave growth. The separation of the precipitation pattern from the main auroral oval is related to properties of the hot and cold plasma within the magnetosphere that enhance EMIC wave growth. [less ▲]

Detailed reference viewed: 23 (0 ULiège)
Full Text
Peer Reviewed
See detailThe Hot-Jupiter Kepler-17b: Discovery, Obliquity from Stroboscopic Starspots, and Atmospheric Characterization
Désert, Jean*-Michel; Charbonneau, David; Demory, Brice*-Olivier et al

in Astrophysical Journal Supplement Series (2011), 197

This paper reports the discovery and characterization of the transiting hot giant exoplanet Kepler-17b. The planet has an orbital period of 1.486 days, and radial velocity measurements from the Hobby ... [more ▼]

This paper reports the discovery and characterization of the transiting hot giant exoplanet Kepler-17b. The planet has an orbital period of 1.486 days, and radial velocity measurements from the Hobby-Eberly Telescope show a Doppler signal of 419.5[SUP]+13.3[/SUP] [SUB]-15.6[/SUB] m s[SUP]-1[/SUP]. From a transit-based estimate of the host star's mean density, combined with an estimate of the stellar effective temperature T [SUB]eff[/SUB] = 5630 ± 100 from high-resolution spectra, we infer a stellar host mass of 1.06 ± 0.07 M [SUB]&sun;[/SUB] and a stellar radius of 1.02 ± 0.03 R [SUB]&sun;[/SUB]. We estimate the planet mass and radius to be M [SUB]P[/SUB] = 2.45 ± 0.11 M [SUB]J[/SUB] and R [SUB]P[/SUB] = 1.31 ± 0.02 R [SUB]J[/SUB]. The host star is active, with dark spots that are frequently occulted by the planet. The continuous monitoring of the star reveals a stellar rotation period of 11.89 days, eight times the planet's orbital period; this period ratio produces stroboscopic effects on the occulted starspots. The temporal pattern of these spot-crossing events shows that the planet's orbit is prograde and the star's obliquity is smaller than 15°. We detected planetary occultations of Kepler-17b with both the Kepler and Spitzer Space Telescopes. We use these observations to constrain the eccentricity, e, and find that it is consistent with a circular orbit (e < 0.011). The brightness temperatures of the planet's infrared bandpasses are T_{3.6\, {\mu m}} = 1880 ± 100 K and T_{4.5\, {\mu m}} = 1770 ± 150 K. We measure the optical geometric albedo A[SUB]g[/SUB] in the Kepler bandpass and find A[SUB]g[/SUB] = 0.10 ± 0.02. The observations are best described by atmospheric models for which most of the incident energy is re-radiated away from the day side. [less ▲]

Detailed reference viewed: 23 (1 ULiège)