相关论文: Detection of a septuple stellar system in formatio…
Circumstellar disks are an essential ingredient of the formation of low-mass stars. It is unclear, however, whether the accretion-disk paradigm can also account for the formation of stars more massive than about 10 solar masses, in which…
Structure of a quasi-stationary stellar cluster is modelled assuming that it is embedded in the gravitational field of a super-massive black hole. Gradual orbital decay of stellar trajectories is caused by the dissipative interaction with…
Most stars are born in the crowded environments of gradually forming star clusters. Dynamical interactions between close-passing stars and the evolving UV radiation fields from proximate massive stars are expected to sculpt the…
Kepler has identified over 600 multiplanet systems, many of which have several planets with orbital distances smaller than that of Mercury -- quite different from the Solar System. Because these systems may be difficult to explain in the…
We examine the formation of planets around binary stars in light of the recently discovered systems Kepler 16, 34 and 35. We conduct hydrodynamical simulations of self gravitating disks around binary systems. The selected binary and disk…
Cosmic metallicity evolution possibly creates the diversity of star formation modes at different epochs. Gravitational fragmentation of circumstellar discs provides an important formation channel of multiple star systems, including close…
(Abridged) Most massive stars are located in multiple systems. The modeling of disk fragmentation, a possible mechanism leading to stellar multiplicity, relies on parallel 3D simulation codes whose agreement remains to be evaluated. Using…
The canonical theory for planet formation in circumstellar disks proposes that planets are grown from initially much smaller seeds. The long-considered alternative theory proposes that giant protoplanets can be formed directly from…
The formation and evolution of a circumstellar disk in magnetized cloud cores is investigated from prestellar core stage until sim 10^4 yr after protostar formation. In the circumstellar disk, fragmentation first occurs due to gravitational…
The discovery of over 400 extrasolar planets allows us to statistically test our understanding of formation and dynamics of planetary systems via numerical simulations. Traditional N-body simulations of multiple-planet systems without gas…
A large fraction of bulgeless disk galaxies contain young compact stellar systems at their centers, in spite of the local gravitational stability of these disks. We evaluate two contrasting hypotheses for the origin of the nuclear star…
The organization of the interstellar medium in disk galaxies obeys the large scale dynamics set by kpc-size structures. Improving our knowledge of how the dense, molecular gas is distributed in a disk is an important step in our…
Recent direct imaging discoveries suggest a new class of massive, distant planets around A stars. These widely separated giants have been interpreted as signs of planet formation driven by gravitational instability, but the viability of…
Stars rarely form in isolation. Nearly half of the stars in the Milky Way have a companion, and this fraction increases in star-forming regions. However, why some dense cores and filaments form bound pairs while others form single stars…
It is widely believed that star clusters form with low star formation efficiencies. With the onset of stellar winds by massive stars or finally when the first super nova blows off, the residual gas is driven out of the embedded star…
We summarize current models of the formation of spheroidal stellar systems. Whereas globular clusters form in an efficient mode of star formation inside turbulent molecular clouds, the origin of galactic spheroids, that is bulges, dwarf…
We study the orbital architecture of multi-planet systems detected by the Kepler transit mission using N-body simulations, focusing on the orbital spacing between adjacent planets in systems showing four or more transiting planets. We find…
The Kepler mission has discovered about a dozen circumbinary planetary systems, all containing planets on ~ 1 AU orbits. We place bounds on the locations in the circumbinary protoplanetary disk, where these planets could have formed through…
We find that, under certain conditions, protoplanetary disks may spontaneously generate multiple, concentric gas rings without an embedded planet through an eccentric cooling instability. Using both linear theory and non-linear…
Observations from optical to centimeter wavelengths have demonstrated that multiple systems of two or more bodies is the norm at all stellar evolutionary stages. Multiple systems are widely agreed to result from the collapse and…