Stars are formed inside large molecular clouds due to gravitational collapse. However, the collapsing processes are complicated by pressure, turbulence, magnetic field, angular momentum, stellar feedback, etc. in various length scales, leading to the formation and evolution of substructures within clouds, including filaments, clumps, cores, disks, jets and outflows, young stellar objects (YSOs), and then protostars and planets. The study can thus be broken down into the following:
- Formation of filaments and their evolution to dense cores: Study the properties (i.e., size, morphology, density, temperature, rotation, angular momentum, infall, turbulence, magnetic field) of filaments and dense cores, and connect the two. We can then also correlate the resulting Core Initial Mass Function (IMF) with Stellar IMF.
- Formation of stars in dense cores: Study (i) the initial conditions of dense cores in differet scales by mapping the first hydrostatic cores, prestellar cores, and corinos; (ii) the effects of pressure, turbulence, magnetic field, and angular momentum in gravitational collapse by studying ambipolar diffusion, magnetic braking, fragmentation, envelope flattening, pseudo-disk and disk formation; (iii) the disk accretion process due to disk viscosity, gravitational instability, and magneto-rotational instability, as well as the mass-loss process in jet and wind, and then link the two processes; and (vi) if the time variability in accretion, jet ejection, and outburst can be caused by star-disk interaction, gravitational instability, binary (either stellar or planetary) companion. We will also study the multiplicity of protostars and the magnetospheric activities of YSOs.
- Protoplanetary Disks and Planet Formation: Investigate planet formation by detecting protoplanets in disks, studying disk properties (e.g., 3D structure, density, temperature, magnetic field, turbulence, dust-to-gas ratio, mass, dust property, asymmetric features, grain growth), and connecting small-scale physics (e.g., turbulence, vortex, grain growth, dust evolution, viscosity, gravitational instability, disk wind) to large-scale structures (e.g., spiral arms, arcs, gaps, rings). How are non-ideal MHD shocks related to stellar core and giant planet formation?
- Astrochemistry: Organic molecules and water are detected around YSOs. What are their origins and can they lead to life? Shocks are detected in jets and outflows. What are the shock chemistry, and thus the resulting molecules synthesis and chemical clocks? Can we extend these to astrochemistry-related topics in the extragalactic context?
Large single-dish radio telescopes such as JCMT and potentially AtLAST/LST can be used to study the large-scale structures. High-resolution radio interferometers such as SMA, ALMA, and potentially ngVLA, can be used to study the small-scale structures. Infrared and optical facilities such as CFHT, Subaru, and potentially E-ELT/METIS or TMT, can be used to map the structures in various scales. TAOS II and Subaru can be used to study Solar System. Various facilities outside the ASIAA collaboration, e.g., NOEMA, VLA, and JWST can also be useful for our studies. Moreover, theoretical models and simulations from Theory group, as well as algorithms and analysis techniques including machine learning and line identification will be developed to study the topics above.
In order to increase our international visibility and consolidate our internal collaboration, we have been discussing about setting up a center for star and planet formation. This seems timely because we indeed have enough faculty members covering various parts.