Molecules with ALMA at Planet-forming Scales (MAPS). XI. CN and HCN as Tracers of Photochemistry in Disks
نویسندگان
چکیده
UV photochemistry in the surface layers of protoplanetary disks dramatically alters their composition relative to previous stages star formation. The abundance ratio CN/HCN has long been proposed trace field various astrophysical objects, however date relationship between CN, HCN, and remains ambiguous. As part ALMA Large Program MAPS (Molecules with at Planet-forming Scales), we present observations CN N=1-0 transitions 0.3'' resolution towards five disk systems. All show bright emission within $\sim$50-150 au, along a diffuse shelf extending up 600 au. In all sources find that column density increases radius from about unity 100, likely tracing increased penetration enhances selective HCN photodissociation outer disk. Additionally, multiple millimeter dust gaps rings coincide peaks troughs, respectively, ratio, implying some substructures are accompanied by changes more elevated layers. That is generally high (>1) points robust shaping chemical compositions, also means dominant carrier prebiotically interesting nitrile group most radii. We local densities positively correlated despite emitting vertically stratified regions, indicating different chemically linked. This paper special issue Astrophysical Journal Supplement.
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ژورنال
عنوان ژورنال: Astrophysical Journal Supplement Series
سال: 2021
ISSN: ['1538-4365', '0067-0049']
DOI: https://doi.org/10.3847/1538-4365/ac143a