Fractal aggregate analogues for near solar dust properties

I. Mann, H. Okamoto, T. Mukai, H. Kimura, Y. Kitada

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Abstract

The present study compares properties of near solar dust, deduced from inversion of F-corona brightriess data, with calculations of fluffy aggregate particles. It is shown that silicate particles containing a slight amount of absorbing maicrial have temperatures below the blackbody temperature if the impurity amounts to less than 0.1% in volume. This effect is especially signiftcatil for porous particles and points to the existence of such a component, possibly cometary dust, in the solar vicinity. In particular the silicate particles with a large impurity, which show a higher temperature than the blackbody at the same solar distance, sublimate at a larger soiar distance. As the impurity decreases, the sublimation starts closer to the sun and the pure silicate, if it would exist, would survive even al about 2 sotar radii from the sun. This result which is based oncalctilations that apply model materials, may possibly explain the wide extended zone of sublimation derived from F-corona brightness data. Another finding of our calculations is an unexpected enhancement of temperature of the two-component aggregates. Namely the silicate aggregate with absorbing impurities attains higher temperature even than the pure carbon. This happens when the volume fraction of absorbing material exceeds 1% and the aggregate with a fractal dimension of 2.98 is located below about 100 solar radii from the sun; this critical solar distance depends on the volume fraction of absorbing material. A similar trend was also seen in the compact particle consisting of two components. This comes from the complex dependence of the energy loss from the particle on the temperature.

Original languageEnglish
Pages (from-to)1011-1018
Number of pages8
JournalAstronomy and Astrophysics
Volume291
Publication statusPublished - Jan 1 1994
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science

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    Mann, I., Okamoto, H., Mukai, T., Kimura, H., & Kitada, Y. (1994). Fractal aggregate analogues for near solar dust properties. Astronomy and Astrophysics, 291, 1011-1018.