On the Detection of the Signature of Silicon Nanoparticle Dust Grains in Coronal Holes

Abstract

We report on polarization measurements in the Fe XIII line at 1074.7 nm made during the total solar eclipse of 2001 June 21, which yielded the first signature of interplanetary dust in the inner corona. In the first-ever images at this wavelength, the signature of dust appears as a tangentially polarized emission in the radial extension of the low-temperature and low-density coronal holes as opposed to a predominantly radial polarization direction in the rest of the corona. The observed emission and polarization are attributed to fluorescence from silicon nanoparticle dust grains in the inner corona.