Search Publications
New findings on the prototypical Of?p stars
Nazé, Y.; Rauw, G.; De Becker, M. +3 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 …
Chemical composition of A and F dwarfs members of the Hyades open cluster
Fossati, L.; Gebran, M.; Monier, R. +1 more
Aims: Abundances of 15 chemical elements have been derived for 28 F and 16 A stars members of the Hyades open cluster in order to set constraints on self-consistent evolutionary models that include radiative and turbulent diffusion.
Methods: A spectral synthesis, iterative procedure was applied to derive the abundances from selected high…
What ignites on the neutron star of 4U 0614+091?
Smith, D. A.; in't Zand, J. J. M.; Sánchez-Fernández, C. +10 more
The low-mass X-ray binary 4U 0614+091 is a source of sporadic thermonuclear (type I) X-ray bursts. We find bursts with a wide variety of characteristics in serendipitous wide-field X-ray observations by the WATCH on EURECA, the ASM on RXTE, the WFCs on BeppoSAX, the FREGATE on HETE-2, the IBIS/ISGRI on INTEGRAL, and the BAT on Swift, as well as po…
The solar type protostar IRAS16293-2422: new constraints on the physical structure
Maret, S.; Ceccarelli, C.; Lis, D. C. +5 more
Context. The low mass protostar IRAS16293-2422 is a prototype Class 0 source in studies of the chemical structure during the initial phases of life of solar type stars.
Aims: To derive the chemical structure accurately, a precise determination of the source physical structure is required. The goal of this study is to derive the structure of I…
Water in low-mass star-forming regions with Herschel . HIFI spectroscopy of NGC 1333
de Graauw, Th.; Liseau, R.; Braine, J. +64 more
“Water In Star-forming regions with Herschel” (WISH) is a key programme dedicated to studying the role of water and related species during the star-formation process and constraining the physical and chemical properties of young stellar objects. The Heterodyne Instrument for the Far-Infrared (HIFI) on the Herschel Space Observatory observed three …
Near-IR integral field spectroscopy of ionizing stars and young stellar objects on the borders of H II regions
Martins, F.; Zavagno, A.; Bouret, J. C. +2 more
Aims: We study three Galactic H ii regions - RCW 79, RCW 82, and RCW 120 - where triggered star formation is taking place. Two stellar populations are observed: the ionizing stars of each H ii region and young stellar objects on their borders. Our goal is to show that they represent two distinct populations, as expected from successive star-f…
Spatial distribution of interstellar dust in the Sun's vicinity. Comparison with neutral sodium-bearing gas
Lallement, R.; Vergely, J. -L.; Raimond, S. +1 more
Aims: 3D tomography of the interstellar dust and gas may be useful in many respects, from the physical and chemical evolution of the interstellar medium itself to foreground decontamination of the cosmic microwave background, or various studies of the environments of specific objects. However, while spectral data cubes of the galactic emissio…
Radiolysis of ammonia-containing ices by energetic, heavy, and highly charged ions inside dense astrophysical environments
Pilling, S.; Seperuelo Duarte, E.; da Silveira, E. F. +4 more
Deep inside dense molecular clouds and protostellar disks, interstellar ices are protected from stellar energetic UV photons. However, X-rays and energetic cosmic rays can penetrate inside these regions triggering chemical reactions, molecular dissociation, and evaporation processes. We present experimental studies of the interaction of heavy, hig…
Photospheric activity, rotation, and radial velocity variations of the planet-hosting star CoRoT-7
Aigrain, S.; Alonso, R.; Auvergne, M. +11 more
Context. The CoRoT satellite has recently discovered the transits of an Earth-like planet across the disc of a late-type magnetically active star dubbed CoRoT-7, while a second planet was detected after filtering out the radial velocity (hereafter RV) variations due to stellar activity.
Aims: We investigate the magnetic activity of CoRoT-7 an…
First results of the Herschel key program ``Dust, Ice and Gas In Time'' (DIGIT): Dust and gas spectroscopy of HD 100546
Waters, L. B. F. M.; Maret, S.; Güdel, M. +40 more
Context. We present far-infrared spectroscopic observations, taken with the Photodetector Array Camera and Spectrometer (PACS) on the Herschel Space Observatory, of the protoplanetary disk around the pre-main-sequence star HD 100546. These observations are the first within the DIGIT Herschel key program, which aims to follow the evolution of dust,…