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.
|Number of pages||8|
|Journal||Astronomy and Astrophysics|
|Publication status||Published - Jan 1 1994|
All Science Journal Classification (ASJC) codes
- Astronomy and Astrophysics
- Space and Planetary Science