Complex organic molecules in protoplanetary disks: X-ray photodesorption from methanol-containing ices

Astrophysical observations show complex organic molecules (COMs) in the gas phase of protoplanetary disks. X-rays emitted from central young stellar object (YSO) that irradiate interstellar ices disk, followed by ejection phase, are a possible route to explain abundances observed cold regions. This process, known as X-ray photodesorption, needs be quantified for methanol-containing ices. We aim at experimentally measuring photodesorption yields methanol and its photo-products binary mixed ices: $^{13}$CO:CH$_3$OH ice H$_2$O:CH$_3$OH ice. irradiated these 15 K with 525 - 570 eV range. The release species was monitored quadrupole mass spectrometry, were derived. For ice, CH$_3$OH yield is estimated 10$^{-2}$ molecule/photon 564 eV. larger COMs, which can attributed either ethanol, dimethyl ether, and/or formic acid, detected 10$^{-3}$ molecule/photon. When water, previous COMs not detected. induced chemistry, dominated low-energy secondary electrons, found main mechanism explains results. also provide desorption applicable disk environments astrochemical models. emission YSOs should participate enrichment such regions because