Planet formation in slightly inclined binary systems
1 Department of Astronomy, Nanjing University, Nanjing, Jiangsu 210093, China
2 Department of Astronomy, University of Florida, Gainesville, FL 32611-2055, USA
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One of the major problems of planet formation in close binary systems, such as α Centauri AB, is the formation of planetary embryos or cores by mutual accretion of km-sized planetesimals. In this contribution, we test the planetesimal accretion in such close binary systems but with small inclinations iB = 0.1–10° between the binary orbital plane and the gas disk plane. Compared to previous studies (coplanar case with iB = 0), we find that (1) planetesimal disk is stratified in the vertical direction and planetesimals are redistributed on different orbit groups with respect to their sizes, thus (2) collisions between similar-sized bodies dominate, leading to low dV and favoring planetesimal accretion (3) the planetesimal collision timescale at 1–2 AU is estimated as: T ∼ (1 + 100iB) × 103 yrs, where 0 ≤ iB ≤ 10°. As a conclusion, although planetesimal accretion are much more favored in slightly inclined binary systems, it is significantly less efficient and slowed-down as compared to the single-star case.
© Owned by the authors, published by EDP Sciences, 2011