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We investigate the gas structures around young binary stars by using three-dimensional numerical simulations. Each model exhibits circumstellar disks, spiral arms, and a circumbinary disk with an inner gap or cavity. The circumbinary disk has an asymmetric pattern rotating at an angular velocity of approximately one-fourth of the binary orbit of the moderate-temperature models. Because of this asymmetry, the circumbinary disk has a density bump and a vortex, both of which continue to exist until the end of our calculation. The density bump and vortex are attributed to enhanced angular momentum, which is promoted by the gravitational torque of the stars. In a hot model ($c ge 2.0$), the asymmetry rotates considerably more slowly than in the moderate-temperature models. The cold models ($c le 0.02$) exhibit eccentric circumbinary disks, the precession of which is approximated by a secular motion of the ballistic particles. The asymmetry in the circumbinary disk does not depend on the mass ratio, but it becomes less clear as the specific angular momentum of the infalling envelope increases. The relative accretion rate onto the stars is sensitive to the angular momentum of the infalling envelope. For envelopes with constant angular momentum, the secondary tends to have a higher accretion rate than the primary, except in very low angular momentum cases. For envelopes with a constant angular velocity, the primary has a higher accretion rate than the secondary because gas with low specific angular momentum falls along the polar directions.
High-mass multiples might form via fragmentation of self-gravitational disks or alternative scenarios such as disk-assisted capture. However, only few observational constraints exist on the architecture and disk structure of high-mass protobinaries a
We present SubMillimeter-Array observations of a Keplerian disk around the Class I protobinary system L1551 NE in 335 GHz continuum emission and submillimeter line emission in 13CO (J=3-2) and C18O (J=3-2) at a resolution of ~120 x 80 AU. The 335-GHz
We report the ALMA Cycle 2 observations of the Class I binary protostellar system L1551 NE in the 0.9-mm continuum, C18O (3-2), 13CO (3-2), SO (7_8-6_7), and the CS (7-6) emission. At 0.18 (= 25 AU) resolution, ~4-times higher than that of our Cycle
Galaxy flybys are as common as mergers in low redshift universe and are important for galaxy evolution as they involve the exchange of significant amounts of mass and energy. In this study we investigate the effect of minor flybys on the bulges, disk
We present the first near-IR scattered light detection of the transitional disk associated with the Herbig Ae star MWC 758 using data obtained as part of the Strategic Exploration of Exoplanets and Disks with Subaru, and 1.1 micron HST/NICMOS data. W