JpGU-AGU Joint Meeting 2020

Presentation information

[J] Poster

P (Space and Planetary Sciences ) » P-CG Complex & General

[P-CG27] Origin and evolution of materials in space

convener:Hideko Nomura(Division of Science, National Astronomical Observatory of Japan), Takafumi Ootsubo(Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency), Hitoshi Miura(Graduate School of Natural Sciences, Department of Information and Basic Science, Nagoya City University), Aki Takigawa(Department of Earth and Planetary Science, The University of Tokyo)

[PCG27-P04] Formation of Complex Organic Molecules via Ice Mantle Reactions in Protoplanetary Disks

Chen-En Wei1, *Hideko Nomura2, Catherine Walsh3, Patrice Theule4 (1.Department of Earth and Planetary Sciences, Tokyo Institute of Technology, 2.Division of Science, National Astronomical Observatory of Japan, 3.University of Leeds, 4.Aix-Marseille Universite)

Keywords:protoplanetary disks, astrochemistry, formation of organic molecules

We have contracted chemical reaction network with ice mantle reactions in addition to gas-phase reactions, gas-grain interaction, and grain-surface reactions in order to investigate their effect on formation of complex organic molecules in protoplanetary disks. As the reaction rate of the ice mantle reactions, we have developed a formula based on the recent laboratory experiments which suggest crystallization of water ice induces the mantle reactions. Periodic FU Ori-type outbursts, which sometimes observed in young protostellar objects, are considered as a heat source required for the ice mantle reaction. Our calculations show that the ice mantle reactions occur efficiently at the temperature of >120K, where the time scale of the ice mantle reaction is sufficiently shorter than the time scale of the outbursts, and produce sufficient amount of ammonium carbamate, which accounts for the broad absorption features observed in the reflected spectra of the comet 67P/Churyumov-Gerasimenko in the Rosetta mission. We simply estimate the temperature of possible comet forming regions in the protoplanetary disks, showing that the mass accretion rate of 10-5 solar mass per year is required in order to explain the heating source to produce the ammonium carbamate by FU Ori-type outbursts. The effect of the ice mantle reactions depends on the structure of ices, namely the thermal history of small bodies and has room for further improvement in future work.