A Balloon Observation of the Thermal Radiation from the Circumsolar Dust Cloud in the 1983 Total Eclipse

Abstract

During the totality on June 11, 1983 in East Java, Indonesia, a near infrared photometric observation of the solar corona was made using a stratospheric balloon, which was successfully launched by a joint team of ISAS, Japan and LAPAN, Indonesia. The surface brightness distributions in four near infrared bands : at 1.25, 1.65, 2.25 and 2.8 µm, have been obtained in the outer coronal region. Noticeable excess emissions superposed on the strong coronal background emission have been recorded in the scan profiles at 1.25 and 1.65 µm, and less conspicuously at 2.25 µm as well, at about 4 R_⊙ from the sun. From the observed spectral and spatial characteristics, the excess emission component appears to originate in the thermal radiation from the circumsolar dust ring made of relatively large particles of about 100 µm in radius and with the olivine-like optical properties.