EUV-Induced CO₂ Formation on Water-Covered Carbonaceous Dust: The Role of Dust Thickness and Type of Carbon Dust

Chun-Yi Lee^1*, Ko-Ju Chuang², Yen-Yu, Hsu¹, Gael Rouillé³, Cornelia Jäger³, Yu-Jung Chen¹

¹Department of Physics, National Centeral University, Taoyuan, Taiwan
²Laboratory for Astrophysics, Leiden Observatory, Leiden University, Leiden, Netherlands
³Laboratory Astrophysics Group of the Max Planck Institute for Astronomy at the Friedrich Schiller University Jena, Institute of Solid State Physics, Jena, Germany

* Presenter:Chun-Yi Lee, email:kailee@phy.ncu.edu.tw

Carbonaceous dust, a prevalent component of interstellar dust grains, is considered a strong candidate for the production of solid-phase CO₂ ice through reactions with H₂O ice. This chemical pathway may occur even prior to CO freeze-out. In this study, two types of carbon dust samples were coated by a fixed layer of water and then irradiated with extreme ultraviolet (EUV) light. The formation of CO₂ on both hydrogenated amorphous carbon (a-¹³C:H) and amorphous carbon (a-¹³C) demonstrated a linear relationship with the thickness of the dust layer. Furthermore, a refractory ¹³C≡¹³C feature was detected in a-¹³C:H dust sample, which holds significant for interpreting astronomical observation.

Keywords: Carbonaceous dust grains, EUV light, hydrocarbon dust, Astrochemistry