The influence of the dust-free zone on F-corona brightness

This presentation is related to model calculations of the circumsolar dust brightness that is seen in the F-corona and inner Zodiacal light. We calculate the brightness integral that includes the size distribution of the interplanetary dust, the spatial distribution, and the scattering properties. The scattering properties are estimated with Mie calculations of spherical particles consisting of astronomical silicate. We consider different size distributions of the dust particles with sizes between 1 nanometre - 100 micrometre. It was recently discussed that the extension of the dust-free zone can be inferred from the slope of the F-corona brightness seen in new observations received from the WISPR instrument on the NASA Parker Solar Probe (Stenborg et al., 2020). We, therefore, investigate the influence of the dust-free zone on the brightness and compare it to the influence that the dust size distribution has.

References

1. G. Stenborg, R. A. Howard, P. Hess, B. Gallagher, PSP/WISPR observations of dust density depletion near the Sun I. Remote observations to 8 Rsol from an observer between 0.13-0.35 AU, A&A, Forthcoming article, 2020. DOI: 10.1051/0004-6361/202039284