Importance of source structure on complex organics emission

Context. Complex organic molecules (COMs) are often observed toward embedded Class 0 and I protostars. However, not all protostars exhibit COM emission. Aims. The aim is to study variations in methanol (CH 3 OH) emission use this as an observational tracer of hot cores test if the absence CH OH can be linked source properties. Methods. A sample 148 low-mass high-mass investigated using new archival observations with Atacama Large Millimeter/submillimeter Array (ALMA) that contain lines its isotopologues. Data for additional 36 sources added from literature, giving a total 184 different sources. warm ( T ? 100 K) gaseous mass, M CH3OH , determined each primarily optically thin isotopologues compared simple toy model spherically symmetric infalling envelope passively heated by central protostar. Results. scatter more than four orders magnitude found among protostars, values ranging between 10 ?7 ? ?10 ?11 . On average, protostellar systems seem have less (?10 ?10 ) younger (~10 ). High-mass our show up ~10 ?3 To take into account effect source’s overall mass on normalized defined / dust,0 where cold plus dust disk inner within fixed radius measured ALMA continuum. correlation L bol found. Excluding upper limits, power-law fit masses results ? 0.70±0.05 over range ?1 6 This good agreement model, which predicts increases 0.70 due snow line moving outward. Sources size equivalent or smaller estimated K fall ? best-fit whereas significantly larger disks two lower. Conclusions. rich implies thermal structure envelopes these likely strongly affected disk. based disagreement we suggest such result colder gas thus fewer COMs phase. Additionally, thick hide COMs. Advanced modeling necessary quantify effects and/or continuum optical depth presence young systems.