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Consequences of proton and alpha anisotropies in the solar wind: Hybrid simulations
Goldstein, Bruce E.; Neugebauer, Marcia; Gary, S. Peter +3 more
Alfvén fluctuations propagating away from the Sun in the solar corona and solar wind transfer energy via cyclotron resonances to ions of successively larger charge-to-mass ratios. This can yield T⟂/T∥ > 1 for each ion species, where the subscripts refer to directions relative to the background magnetic field. If these anis…
A measure from line-of-sight magnetograms for prediction of coronal mass ejections
Falconer, D. A.; Moore, R. L.; Gary, G. A.
From a sample of 17 vector magnetograms of 12 bipolar active regions we have recently found (1) that a measure of the overall nonpotentiality (the overall twist and shear in the magnetic field) of an active region is given by the strong shear length LSS, the length of the portion of the main neutral line on which the observed transverse…
Experimental simulation of Titan's atmosphere: Detection of ammonia and ethylene oxide
Coustenis, A.; Coll, P.; Raulin, F. +1 more
For several years now, an experimental simulation of Titan's atmosphere has been on going at LISA. A cold plasma is established in a gas mixture representative of the atmosphere of the satellite. In these experiments, more than 70 organic compounds have been identified, including the first identification in this type of experimental simulation of …
Multiwavelength cosmological simulations of elliptical galaxies
Kawata, D.; Gibson, B. K.
We study the chemodynamical evolution of elliptical galaxies and their X-ray and optical properties using high-resolution cosmological simulations. Our tree N-body/smoothed particle hydrodynamics (SPH) code includes a self-consistent treatment of radiative cooling, star formation, supernovae feedback and chemical enrichment. We present a series of…
Modeling gas-phase H2O between 5 µ m and 540 µ m toward massive protostars
van Dishoeck, E. F.; Bergin, E. A.; Melnick, G. J. +4 more
We present models and observations of gas-phase H2O lines between 5 and 540 mu m toward deeply embedded massive protostars, involving both pure rotational and ro-vibrational transitions. The data have been obtained for 6 sources with both the Short and Long Wavelength Spectrometers (SWS and LWS) on board the Infrared Space Observatory (…
The circumstellar envelope of the C-rich post-AGB star HD 56126
Waters, L. B. F. M.; Hony, S.; de Koter, A. +1 more
We present a detailed study of the circumstellar envelope of the post-asymptotic giant branch ``21 mu m object'' HD 56126. We build a detailed dust radiative transfer model of the circumstellar envelope in order to derive the dust composition and mass, and the mass-loss history of the star. To model the emission of the dust we use amorphous carbon…
Revisiting the solid HDO/H2O abundances
Dartois, E.; Geballe, T. R.; d'Hendecourt, L. +3 more
We revisit the reported detection and upper limits on HDO in ice mantles present in the molecular cloud environments of the massive young protostars Gl 2136 and W33 A, using independent VLT-ISAAC and UKIRT-CGS4 spectroscopic observations. We also present VLT and UKIRT spectra of RAFGL 7009 near the HDO absorption wavelength and reanalyze the ISO-S…
The Star Formation History of NGC 1705: A Poststarburst Galaxy on the Verge of Activity
Leitherer, Claus; Greggio, L.; Tosi, M. +2 more
We infer the star formation history in different regions of the blue compact dwarf NGC 1705 by comparing synthetic color-magnitude diagrams with the Hubble Space Telescope optical and near-infrared photometry. We find that NGC 1705 is not a young galaxy, because its star formation commenced at least 5 Gyr ago. On the other hand, we confirm the exi…
A Comprehensive Study of the L1551 IRS 5 Binary System
Hartmann, Lee; Calvet, Nuria; Muzerolle, James +2 more
We model the Class I source L1551 IRS 5, adopting a flattened infalling envelope surrounding a binary disk system and a circumbinary disk. With our composite model, we calculate self-consistently the spectral energy distribution of each component of the L1551 IRS 5 system, using additional constraints from recent observations by ISO, the water ice…
GRB 011121: A Collimated Outflow into Wind-blown Surroundings
Mitrofanov, I.; Pian, E.; Palazzi, E. +31 more
We report optical and near-infrared follow-up observations of GRB 011121 collected predominantly at ESO telescopes in Chile. We discover a break in the afterglow light curve after 1.3 days, which implies an initial jet opening angle of about 9°. The jet origin of this break is supported by the fact that the spectral energy distribution is achromat…