Presentation #0702 in the session “Planetary Interiors”.
The chemical composition of planets and comets is inherited from that of the parent protoplanetary disk. Precursors to larger, biologically-relevant organic molecules are detected throughout interstellar space, but determining the presence and properties of these molecules during the process of planet formation requires high angular resolution and sensitivity observations. We present observations of organic molecules in five protoplanetary disks observed within the ‘Molecules with ALMA at Planet-Forming Scales’ (MAPS) ALMA Large Program. These molecules are precursors to larger, prebiotic molecules with hydrocarbon and nitrile functional groups. We robustly detect all targeted species in four of the protoplanetary disks (along with generally weaker emission or marginal detections only in IM Lup). We find a range of morphologies — central peaks, single or double rings — with no clear pattern between molecule and/or disk. Emission is generally compact and on scales comparable with the millimetre continuum, indicative of a relationship with dust grains (and therefore the location of the midplane ice reservoir). Our analysis of this high resolution and sensitivity data reveals reveals 5-10 times more column of material in the inner (<100 au) of the disks when compared with previous studies. We find good agreement between the ratio of small-to-large nitriles in the disks and remote observations of comets. Our results indicate that the protoplanetary disks studied here possess significant reservoirs of organic material that has obtained a similar level of chemical complexity to that in our own solar system.