Search Publications
The last revolution of new comets: the role of stars and their detectability
Rickman, H.; Valsecchi, G. B.; Fouchard, M. +1 more
Context. This work is a follow-up of a previous study, where we simulated the dynamical evolution of the Oort Cloud over 5 Gyr with special attention to the injection of comets into observable orbits.
Aims: We wish to clarify how comet injection operates with two types of perturbers: Galactic tides and passing stars. We illustrate why attempt…
HD 5388 b is a 69 MJup companion instead of a planet
Queloz, D.; Sahlmann, J.; Ségransan, D. +1 more
We examined six exoplanet host stars with non-standard Hipparcos astrometric solution, which may be indicative of unrecognised orbital motion. Using Hipparcos intermediate astrometric data, we detected the astrometric orbit of HD 5388 at a significance level of 99.4% (2.7 σ). HD 5388 is a metal-deficient star and hosts a planet candidate with a mi…
The fundamental parameters of the roAp star γ Equulei
Chesneau, O.; Goldfinger, P. J.; Sturmann, J. +18 more
Context. A precise comparison of the predicted and observed locations of stars in the H-R diagram is needed when testing stellar interior theoretical models. For doing this, one must rely on accurate, observed stellar fundamental parameters (mass, radius, luminosity, and abundances).
Aims: We determine the angular diameter of the rapidly osci…
The (sub-)millimeter SED of protoplanetary disks in the outskirts of the Orion nebula cluster
Robberto, M.; Testi, L.; Natta, A. +5 more
We present the sub-mm/mm SED for a sample of eight young circumstellar disks in the outer regions of the Orion nebula cluster (ONC). New observations were carried out at 2.9 mm with the CARMA array and for one disk, 216-0939, at 3.3 and 6.8 mm with ATCA. By combining these new millimeter data with literature measurements at sub-millimeter waveleng…
Discovery of the X-ray selected galaxy cluster XMMU J0338.8+0021 at z = 1.49. Indications of a young system with a brightest galaxy in formation
Böhringer, H.; Rosati, P.; Šuhada, R. +11 more
We report the discovery of a galaxy cluster at z = 1.490 originally selected as an extended X-ray source in the XMM-Newton Distant Cluster Project. Further observations carried out with the VLT-FORS2 spectrograph allowed the spectroscopic confirmation of seven secure cluster members, providing a median system redshift of z = 1.490 ± 0.009. The col…
First hyperfine resolved far-infrared OH spectrum from a star-forming region
van Dishoeck, E. F.; Bergin, E. A.; Goicoechea, J. R. +9 more
OH is an important molecule in the H2O chemistry and the cooling budget of star-forming regions. The goal of the Herschel key program "Water In Star-forming regions with Herschel" (WISH) is to study H2O and related species during protostellar evolution. Our aim in this Letter is to assess the origin of the OH emission from st…
Quasi-ballistic and superdiffusive transport for impulsive solar particle events
Zimbardo, G.; Trotta, E. M.
Context. The propagation of solar energetic particles encompasses a number of transport regimes, which goes from diffusive transport to scatter-free propagation. On the other hand, numerical simulations in the presence of magnetic turbulence, as well as the analysis of propagating particles accelerated at interplanetary shocks, show that superdiff…
The scaling of X-ray variability with luminosity in ultra-luminous X-ray sources
Zezas, A.; Papadakis, I.; Reig, P. +1 more
Aims: We investigate the relationship between the X-ray variability amplitude and X-ray luminosity for a sample of 14 bright ultra-luminous X-ray sources (ULXs) with XMM-Newton/EPIC data, and compare it with the well-established, similar relationship for active galactic nuclei (AGN).
Methods: We computed the normalised excess variance in…
EUV lines observed with EIS/Hinode in a solar prominence
Heinzel, P.; Schmieder, B.; Watanabe, T. +1 more
Context. During a multi-wavelength observation campaign with Hinode and ground-based instruments, a solar prominence was observed for three consecutive days as it crossed the western limb of the Sun in April 2007.
Aims: We report on observations obtained on 26 April 2007 using EIS (Extreme ultraviolet Imaging Spectrometer) on Hinode. They are…
Hinode observations and 3D magnetic structure of an X-ray bright point
Del Zanna, G.; Maclean, R. C.; Alexander, C. E.
Aims: We present complete Hinode Solar Optical Telescope (SOT), X-Ray Telescope (XRT)and EUV Imaging Spectrometer (EIS) observations of an X-ray bright point (XBP) observed on the 10, 11 of October 2007 over its entire lifetime (~12 h). We aim to show how the measured plasma parameters of the XBP change over time and also what kind of similar…