PLANETESIMAL DYNAMICS IN INCLINED BINARY SYSTEMS: THE ROLE OF GAS-DISK GRAVITY

Journal Article · Fri Apr 20 04:00:00 EDT 2012 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/749/2/172· OSTI ID:22020354

Gang, Zhao; Jiwei, Xie; Jilin, Zhou ^[1]; Lin, Douglas N. C., ^[2]

---

1. Department of Astronomy and Key Laboratory of Modern Astronomy and Astrophysics in the Ministry of Education, Nanjing University, Nanjing 210093 (China)
2. UCO/Lick Observatory, University of California, Santa Cruz, CA 95064 (United States)

We investigate the effects of gas-disk gravity on planetesimal dynamics in inclined binary systems, where the circumprimary disk plane is tilted by a significant angle (i{sub B} ) with respect to the binary disk plane. Our focus is on the Lidov-Kozai mechanism and the evolution of planetesimal eccentricity and inclination. Using both analytical and numerical methods, we find that, on one hand, disk gravity generally narrows down the Kozai-on region, i.e., the Lidov-Kozai effect can be suppressed in certain parts of (or even the whole of) the disk depending on various parameters. In the Kozai-off region, planetesimals would move to orbits close to the midplane of the gas-disk, with the relative angle (i') following a small amplitude periodical oscillation. On the other hand, when we include the effects of disk gravity, we find that the Lidov-Kozai effect can operate even at arbitrarily low inclinations (i{sub B} ), although a lower i{sub B} leads to a smaller Kozai-on region. Furthermore, in the Kozai-on region, most planetesimals' eccentricities can be excited to extremely high values ({approx}1), and such extreme high eccentricities usually accompany orbital flipping, i.e., the planetesimal orbit flips back and forth between anterograde and retrograde. Once a planetesimal reaches very high orbital eccentricity, gas drag damping will shrink the planetesimal orbit, forming a 'hot planetesimal' on a near circular orbit very close to the primary star. Such a mechanism, if replacing the planetesimals and gas drag damping with Jupiters and tidal damping respectively, may lead to a frequent production of hot Jupiters.

• OSTI ID: 22020354
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 2 Vol. 749; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
GRAVITATION
INCLINATION
JUPITER PLANET
ORBITS
PERIODICITY
STAR EVOLUTION
STARS