Measuring molecular abundances in comet C/2014 Q2 (Lovejoy) using the APEX telescope

Area of Science:

• * Planetary Science
• * Astrochemistry
• * Solar System Formation

Background:

• * Comet composition offers insights into early Solar System chemical and physical processes.
• * Long-period comets are pristine remnants from the Solar System's formation.
• * Gaseous volatiles sublimating from cometary comas allow for sensitive compositional studies.

Purpose of the Study:

• * To spectroscopically analyze the molecular composition of comet C/2014 Q2 (Lovejoy).
• * To measure precise molecular production rates of various volatiles.
• * To investigate the origin of organic molecules in comets.

Main Methods:

• * Millimeter spectroscopic observations using the Atacama Pathfinder Experiment (APEX) band 1 receiver.
• * Detection of molecules including HCN, CH3OH, H2CO, and CO.
• * Non-LTE molecular excitation calculations to derive gas production rates.

Main Results:

• * Detection of HCN, CH3OH, H2CO, and CO with precise production rates.
• * Upper limits determined for complex molecules acetaldehyde and formamide.
• * Depleted CO abundance (2.0% relative to water) and low HCN (0.1%) and H2CO (0.2%) abundances observed.
• * Methanol (CH3OH) abundance (2.2% relative to water) is consistent with other comets.

Conclusions:

• * The observed molecular abundances in comet C/2014 Q2 (Lovejoy) provide constraints on Solar System formation models.
• * The data supports the hypothesis that atom addition reactions on cold dust grains contribute to the formation of some cometary organic molecules.