Positional measurements on the eruptive loop prominence of 27 April 1981 and comparison with the X-ray sources

Using the Hα observational data from Yunnan Observatory, we have made position measurements on the eruptive loop prominence of 27 April 1981, and have compared the results with the positions of X-ray sources obtained by the hard X-ray telescope (SXT) on board the HINOTORI satellite. From the results of measurement and comparison, it is suggested that 1) The two mounds A and C at 0830 UT are extensions of two ribbons in the flare near the limb, which started before 0758 UT. 2) The central positions of two X-ray sources at 0756 UT are just situated at the top of the mound A and the mound C, respectively. The Hα footpoint corresponding to the main source of X-rays was behind the solar limb. The second source of X-rays corresponds to C₁ and C₂. 3) The X-ray sources were probably located near the footpoints of loops.