Chemistry in planet-forming regions revealed by ALMA

The Atacama Large Millimeter/submillimeter Array (ALMA) is a telescope in Chile that observes the universe at millimeter wavelengths. ALMA has the resolution and sensitivity to observe emission from cold dust and molecular gas on planet-forming scales. This allows us to probe the planet-building environment around nearby stars on size scales similar to the Solar System. Recent observations with ALMA have revealed the almost ubiquitous presence of dust substructure in disks around nearby young stars, in which the dust has been shepherded into concentric dust rings and asymmetric vortices. One of the proposed origins of this dust structure is the presence of still-forming planets within the disk.

A recent ALMA Large Program involving Leeds' researchers, titled "Molecules with ALMA on Planet-forming Scales" or MAPS, imaged for the first time, the chemistry of planet formation on Solar System size scales (www.alma-maps.info). These data revealed a wealth of chemical diversity, with observed chemical sub-structure usually not coincident with dust sub-structure. It is still not understood why disks exhibit such chemical diversity but it is likely due to the complex interplay between dust, radiation, chemistry, and transport of material.

Determining the origin of chemical sub-structure in disks requires the development of new models of protoplanetary disks that incorporate all of these important physical effects. This project will develop new models of disk chemistry that include the effects of dust evolution and sub-structure, radial transport, and mixing, motivated by current theories on the origin of dust sub-structure in disks. These models will be used to simulate observations to directly compare with the results from the MAPS ALMA Large Program, and to produce suites of diagnostics that will be used to motivate future ALMA proposals.