The chiral puzzle of biological molecules is thought to be closely related the origin life and still a mystery so far. Previously, we proposed new model on life, Nebula-Relay hypothesis, which assumed that Earth originated at planetary system Sun’s predecessor star then filled in pre-solar nebula after its death. As primitive lives existed for long time, did biomolecules form during this period...

The favored theoretical explanation for giant planet formation – in both our solar system and others – is the core accretion model (although it still has some serious difficulties). In this scenario, planetesimals accumulate to build up planetary cores, which then accrete nebular gas. With current opacity estimates for protoplanetary envelopes, this model predicts the formation of Jupiter-mass ...

We study the migration and resonant capture of planetesimals in a planetary system consisting of a gaseous disc analogous to the primordial solar nebula and a Neptune-like planet. Using a simple treatment of the drag force we find that planetesimals are mainly trapped in the 3:2 and 2:1 resonances and that the resonant populations are correlated with the gaseous drag strength in a sense that th...

We consider the possibility that a mass of ∼ 10 − 10M⊙ flows back from the dense shell of planetary nebulae and is accreted by the central star during the planetary nebula phase. This backflowing mass is expected to have a significant specific angular momentum even in (rare) spherical planetary nebulae, such that a transient accretion disk might be formed. This mass might influence the occurren...

Through HST imaging of the inner part of the main-ring of the Helix Nebula together with CTIO 4-m images of the fainter outer parts, we have an unprecedented-quality view of the nearest bright planetary nebula. These images have allowed determination that the main-ring of the nebula is composed of an inner-disk of about 499 diameter (0.52 pc) surrounded by an outer-ring (in reality a torus) of ...