Orbital evolution of planetesimals in gaseous disks

Abstract

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 $e\ll 1$ and $i\ll H/a$, 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 $1-e^2\ll 1$ and $i\ll H/a$ and for $i\gg H/a$. The formulae combined from these limited equations will represent the results of orbital integration unless $e\ge 1$ or $i>\pi -H/a$. 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.

accepted for publication in Earth, Planets and Space, 11 pages, 4 figures

References in corpus (1)

• On the Viability of the Magnetorotational Instability in Circumplanetary Disks

Cited by in corpus (3)

• Rapid formation of Gas Giant Planets via Collisional Coagulation from Dust Grains to Planetary Cores
• Collisional Elongation: Possible Origin of Extremely Elongated Shape of 1I/`Oumuamua
• Runaway Growth of Planetesimals Revisited: Presenting Criteria Required for Realistic Modeling of Planetesimal Growth