2023/03/10 by Norio Ota, Aigen Li, Ota, Norio +1
Chemistry · Engineering · #Advanced Thermodynamic Systems and Engines #Astrophysics of Galaxies (astro-ph.GA) #Atomic and Molecular Clusters (physics.atm-clus) #Earth and Planetary Astrophysics (astro-ph.EP) #FOS: Physical sciences #Molecular Spectroscopy and Structure #SAS software applications and methods #Solar and Stellar Astrophysics (astro-ph.SR)
paper · pdf · doi:10.48550/arxiv.2303.05645
openalex publication_date 2023/03/10 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Protoplanetary disk around a just born young star contains a lot of cosmic dust. especially polycyclic-aromatic-hydrocarbon (PAH), which would become basic component to create biological organics. This study classified many astronomically observed infrared spectra of protoplanetary disks to three typical spectra. Type-A show well known astronomical bands of 6.2, 7.8, 8.6 and 11.3 micrometer. Whereas Type-B included unknown complex bands. Type-(A+B) was their mixed type. We tried to find specific molecule by Density Functional Theory (DFT) calculation. We found that Type-A could be explained by large PAH molecules of (C23H12) and (C53H18), which are hexagon-pentagon combined molecular structure. Background molecule of Type-B was smaller ones of (c-C3H2), (C5H5), (C9H7) and (C12H8). Type-(A+B) was reproduced well by mixing those molecules of A and B. Astronomical detailed observation shows that central star of Type-A has larger mass and higher temperature than that of Type-B. This suggests that at very early stage of our solar system, our protoplanetary disk had been made up by Type-B molecules. It was interesting that (C5H5) and (C9H7) of Type-B molecules has similar molecular structure with biological nucleic-acid on our earth. Type-B molecules was supposed to become the template for synthesizing biological organics and finally for creating our life.