Near-infrared observation of the circumsolar dust emission during the 1983 solar eclipse

Abstract

A near-infrared excess emission superposed on the coronal continuum at ∼4R_⊙ from the Sun was first observed at 2.2 µm by Peterson¹ and MacQueen² during the total solar eclipse in 1966, and was later confirmed by MacQueen² using a balloon-borne coronagraph. Two subsequent observations were made; one³ obtained a similar result, while the other⁴ detected no excess emission. The excess emission was thought to be due to thermal radiation by a dust cloud around the Sun, and interpreted to be interplanetary dust². Brecher et al.⁵, on the other hand, have proposed that the ring is composed of much larger objects (of about 10 km diameter). To obtain more definite information, we have therefore carried out observations of near-infrared brightness distributions of the solar corona, using a balloon-borne photometer at a balloon altitude, during the total eclipse on 11 June 1983 in Indonesia. As we report here, emissions in excess of the strong coronal background emission were recorded in some of the scans at ∼4R_⊙ from the Sun. The spatial distribution of the excess emission implies the existence of a circumsolar ring of dust lying approximately in the ecliptic plane.