Spatially resolving the chemical composition of the planet building blocks
Abstract
The inner regions (0.1-10 au) of protoplanetary discs are the expected birthplace of telluric planets. In those hot regions, solids can experience cyclical annealing, vapourisation, and recondensation. Hot/warm dust grains emit mostly in the IR, notably in N-band (8-13 ?m). Studying their chemistry with the new MIR VLTI instrument MATISSE, which can spatially resolve those regions, requires detailed dust chemistry models. Using radiative transfer, we derived IR spectra of a fiducial static disc model with different inner-disc (<1 au) dust compositions. The latter were derived from condensation sequences computed at LTE for three initial C/O ratios: 0.4 (subsolar), 0.54 (solar), 1 (supersolar). The three scenarios return very different N-band spectra that MATISSE should be able to discriminate. From that, we propose a first interpretation of N-band 'inner-disc' spectra obtained with the former VLTI instrument MIDI on several YSOs, and show recently obtained MATISSE N-band spectra.