Occultation of a Radio Star by the Solar Corona

Abstract

IT has been suggested¹ that the radiation from a radio star might be cut off by refraction in the solar corona, even when the angular separation of the sun and the star is several times the angular radius of the visible disk (R_⊙). The existing data on the coronal electron density have been used for predicting the effective radius of the sun for occultation on various frequencies¹. Link² has calculated the circumstances of the occultation for 1952 and has also shown that the observed intensity of the radiation from the radio star should increase before the actual occultation. Attempts were made to observe these effects in June 1950 and 1951 when the radio star in Taurus (05.01) passed within an angular distance of about 4.5 R_⊙ from the sun's centre, but intense sunspot radiation prevented any useful results being obtained.