Discovery and study of Comet 67P/Churyumov--Gerasimenko, the main target of the Rosetta space mission

Abstract

Rosetta, a European space vehicle, which was 15 years in development, headed for short-period Comet 67P/Churyumov-Gerasimenko in February 2004. In September 1969 S. Gerasimenko and the author went to the Alma-Ata Astrophysical Institute to carry out a survey of short-period and new comets. At a later date of that month, the author examined the exposure of Comet 32P/Comas Sola made on September 11.92 UT, 1969 and found a cometary object near the plate centre. The author assumed it to be the expected short-period Comet 32P/Comas Sola. Later explorations at the Kyiv University revealed that this comet's position differed from predicted calculations for Comet 32P by 1.8°. It was a new comet. The comet had an apparent magnitude of 13 and the faint tail about 1 arcmin in length at a position angle of 280°. On the basis of the observations of Comet 67P obtained in Nizhny Arkhyz with the help of the 6-m BTA reflector of the SAO RAS, some physical parameters of the cometary plasma tail (coefficients of diffusion D_||, D_bot and induction of magnetic field B) were determined (Jan. 12.105 UT, 1983: D_|| = (5.07\cdot 10¹⁴ -> 1.21\cdot 10¹⁵) cm²/s, D_bot = (5.73\cdot 10¹³ - 1.37\cdot 10¹⁴) cm²/s, B= (46 - 111) nT; Jan. 13.124 UT, 1983: D_|| = (4.67\cdot 10¹⁴ -> 1.14\cdot 10¹⁵) cm²/s, D_bot = (4.30\cdot 10¹³ - 1.05\cdot 10¹⁴) cm²/s, B= (55 - 134) nT). The author hope that the Rosetta space mission will obtain valuable data for solving the fundamental scientific problem on the origin and evolution history of the Solar System.