Search Publications
Implications of the cosmic infrared background for light production and the star formation history in the Universe
Lagache, G.; Puget, J. L.; Gispert, R.
The Cosmic Background due to the integrated radiation from galaxies over the whole life of the Universe is reviewed. We find that this background is well constrained by measurements. The total power in the background is in the range 60-93 nWm-2sr-1. The data show the existence of a minimum separating the direct stellar radiat…
A proper motion study of the globular cluster ω Centauri
Freeman, K. C.; van Leeuwen, F.; Le Poole, R. S. +2 more
A proper motion study is presented of the globular cluster ω Centauri. Based on 100 plates obtained with the Yale-Columbia 66 cm (26 inch) refractor, and ranging in epoch from 1931 till 1935 and 1978 till 1983, differential proper motions are obtained for 9847 stars. The limiting magnitude (photographic) is 16.0 for the centre of the cluster, 16.5…
The structure of the collapsing envelope around the low-mass protostar IRAS 16293-2422
Ceccarelli, C.; Caux, E.; Tielens, A. G. G. M. +4 more
Using H2O, OI and SiO data, we derive the structure of the collapsing envelope around the low-mass protostar IRAS16293-2422 down to r ~ 30 AU. With an accurate model which computes self-consistently the chemical composition, thermal balance and line emission from a collapsing envelope (Ceccarelli et al. 1996), we find that IRAS16293-242…
Multiple shells in IRC+10216: shell properties
Mauron, N.; Huggins, P. J.
We report on the properties of the multiple shells in the circumstellar envelope of IRC+10216, using deep optical imaging, including data from the Hubble Space Telescope. The intensity profiles confirm the presence of thin ( ~ 0farcs5 -3'' ec), limb-brightened shells in the envelope, seen in stellar and ambient Galactic light scattered by dust. Th…
Slow magnetoacoustic waves in coronal loops
Berghmans, D.; Nakariakov, V. M.; Verwichte, E. +1 more
A theoretical model interpreting propagating disturbances of EUV emission intensity, recently observed in coronal loops, is constructed in terms of slow magnetoacoustic waves. The model is one-dimensional and incorporates effects of nonlinearity, dissipation due to finite viscosity and thermal conduction, and gravitational stratification of plasma…
Probing the brown dwarf population of the Chamaeleon I star forming region
Neuhäuser, R.; Comerón, F.; Kaas, A. A.
We present observations of a sample of 13 very low mass stars and brown dwarfs in the central region of the Chamaeleon I star forming cloud. The observations include slitless spectroscopy around Hα to identify new members, low resolution long-slit visible and near-infrared spectroscopy, deep ROSAT PSPC X-ray observations, and ISOCAM mid-infrared o…
ISO-SWS observations of OMC-1: H_2 and fine structure lines
Bertoldi, F.; Drapatz, S.; Rosenthal, D.
Using the Short-Wavelength-Spectrometer on the Infrared Space Observatory (ISO), we obtained near- and mid-infrared spectra toward the brightest H_2 emission peak of the Orion OMC-1 outflow. A wealth of emission and absorption features were detected, dominated by 56 H_2 ro-vibrational and pure rotational lines reaching from H_2 0-0 S(1) to 0-0 S(2…
A spectroscopic study of coronal dimming associated with a coronal mass ejection
Harrison, R. A.; Lyons, M.
Extreme ultraviolet spectroscopic observations of one coronal mass ejection event are used to examine the onset phase of the eruption. We find significant dimming of million K plasmas in the low corona under the ascending CME, the activation of an adjacent prominence and 2 million K `hot spots' which may be associated with the CME footpoints. In p…
The C-C-C bending modes of PAHs: a new emission plateau from 15 to 20 µm
Waters, L. B. F. M.; Hony, S.; Tielens, A. G. G. M. +9 more
We have obtained 2.5-45 mu m spectra of a sample of compact H ii regions, YSOs and evolved stars in order to study the origin and evolution of interstellar Polycyclic Aromatic Hydrocarbon molecules (PAHs). Besides the well-known, strong PAH bands at 3.3, 6.2, 7.7, 8.6, and 11.2 mu m, these spectra reveal for the first time, a ubiquitous emission p…
Mass-radius relations for white dwarf stars of different internal compositions
Althaus, L. G.; Panei, J. A.; Benvenuto, O. G.
The purpose of this work is to present accurate and detailed mass-radius relations for white dwarf (WD) models with helium, carbon, oxygen, silicon and iron cores, and with and without a hydrogen envelope, by using a fully updated stellar evolutionary code. We considered masses from 0.15 Msun to 0.5 Msun for the case of hel…