Science Archives Publication System

Chemical composition of Titan's haze: Are PAHs present?

DOI: 10.1029/2004GL019859 Bibcode: 2004GeoRL..3117S08T

McKay, Christopher P.; Toon, Owen B.; Trainer, Melissa G. +4 more

Previous laboratory studies of haze aerosols analogous to those in Titan's atmosphere have shown evidence of the formation of polycyclic aromatic hydrocarbons (PAHs). If present, PAHs may provide a mechanism for both particle formation and nitrogen incorporation. We have conducted new experiments simulating Titan haze production using an Aerosol M…

2004 • Geophysical Research Letters

Huygens 25

Kinematics of stellar associations: the epicycle approximation and the convergent point method

DOI: 10.1111/j.1365-2966.2004.08012.x Bibcode: 2004MNRAS.352.1199M

Olling, Rob P.; Makarov, Valeri V.; Teuben, Peter J.

Employing analytical and numerical tools, we expound the Galactic epicycle theory to describe the kinematic evolution of stellar, gravitationally unbound associations in the vicinity of the Sun. We estimate the limits of applicability of the analytical epicycle approximation and harmonic vertical motion by numerical integration of test orbits with…

2004 • Monthly Notices of the Royal Astronomical Society

Hipparcos 25

High resolution millimeter imaging of the proto-planetary nebula He 3-1475

DOI: 10.1051/0004-6361:20034139 Bibcode: 2004A&A...414..581H

Bachiller, R.; Forveille, T.; Cox, P. +2 more

We report high resolution (1 arcsec-2 arcsec) imaging of the CO 2-1 line and the millimeter continuum in the proto-planetary nebula He 3-1475. The observations reveal the presence of a massive (∼ 0.6 M_⊙) envelope of molecular gas around the origin of the remarkable bipolar jet system seen in optical images with the HST. The CO kinematic…

2004 • Astronomy and Astrophysics

eHST 24

Orientation and motion of a discontinuity from single-spacecraft measurements of plasma velocity and density: Minimum mass flux residue

DOI: 10.1029/2003JA010230 Bibcode: 2004JGRA..109.3221S

Balogh, A.; Lavraud, B.; Dunlop, M. W. +4 more

A simple analytical solution is presented to the problem of determining the orientation and motion of a one-dimensional discontinuity in plasma velocity and density, measured by a single spacecraft as the discontinuity moves past it. The method developed is called Minimum Massflux Residue (MMR). Illustrations of the method, based on Cluster measur…

2004 • Journal of Geophysical Research (Space Physics)

Cluster 24

Time-dependent ejection velocity model for the outflow of Hen 3-1475

DOI: 10.1051/0004-6361:20035757 Bibcode: 2004A&A...419..991V

Velázquez, P. F.; Raga, A. C.; Riera, A.

We present 2D axisymmetric and 3D numerical simulations of the proto-planetary nebula Hen 3-1475, which is characterized by a remarkably highly collimated optical jet, formed by a string of shock-excited knots along the axis of the nebula. It has recently been suggested that the kinematical and morphological properties of the

2004 • Astronomy and Astrophysics

eHST 24

Impulsive and Gradual Nonthermal Emissions in an X-Class Flare

DOI: 10.1086/381353 Bibcode: 2004ApJ...603..335Q

Qiu, Jiong; Gary, Dale E.; Lee, Jeongwoo

In this paper we present a comprehensive case study of an X-class flare observed on 2001 April 6. The flare consists of two episodes, the first characterized by impulsive spiky bursts and the second by gradual smooth emission at hard X-ray and microwave wavelengths. Emissions in the two episodes are regarded as the impulsive and gradual components…