摘要：Planets are formed from collisional growth of small bodies in a protoplanetary disk. Bodies much larger than approximately 1 m are mainly controlled by the gravity of the host star and experience weak gas drag; their orbits are mainly expressed by orbital elements: semimajor axes a , eccentricities e , and inclinations i , which are modulated by gas drag. In a previous study, \(\dot a\) , \(\dot e\) , and \(\dot i\) were analytically derived for e ≪1 and i ≪ H / a , where H is the scale height of the disk. Their formulae are valid in the early stage of planet formation. However, once massive planets are formed, e and i increase greatly. Indeed, some small bodies in the solar system have very large e and i . Therefore, in this paper, I analytically derive formulae for \(\dot a\) , \(\dot e\) , and \(\dot i\) for 1− e 2 π − H / a . Since the derived formulae are applicable for bodies not only in a protoplanetary disk but also in a circumplanetary disk, I discuss the possibility of the capture of satellites in a circumplanetary disk using the formulae.
