Time-dependent Chemistry of Detritus from Sun-grazing Comets
Abstract
As a sun-grazing comet passes the Sun at perihelion it leaves behind a trail of water vapor and detritus. The latter are grains of stony material that rapidly heat and vaporize in the intense radiation field of the solar photosphere. A large amount of O is produced from both the water and the stony material. The atomic material does not continue along the comet's orbital path but appears to move along the ambient magnetic field. This requires an ionization mechanism that rapidly converts the neutral atoms into ions. We propose two models of the time-dependent chemistry that can be used to calculate the ionization balance of O and Fe. One is an extension of the Haser model to include many stages of ionization but without recombination. The advantage is that an analytic solution can be derived for an arbitrary numbers of ionization stages. Once the time dependence is known it can be converted to the radial profile in either spherical or cylindrical symmetry. The other model integrates in time the equations describing ionization/recombination balance. Both types of solutions can be numerically inverted to estimate the radiance profiles. The models give the same sequence to the ionization stages, but the time dependence and radial profiles are shown to differ. Although we concentrate on the O and Fe chemistry because it is observed from SDO/AIA, any atom can be considered.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2012
- Bibcode:
- 2012AGUFMSH13B2253P
- Keywords:
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- 5422 PLANETARY SCIENCES: SOLID SURFACE PLANETS / Ices;
- 5464 PLANETARY SCIENCES: SOLID SURFACE PLANETS / Remote sensing;
- 7549 SOLAR PHYSICS;
- ASTROPHYSICS;
- AND ASTRONOMY / Ultraviolet emissions