Complex organics in space from Solar System to distant galaxies

Abstract

Recent observational and experimental evidence for the presence of complex organics in space is reviewed. Remote astronomical observations have detected ∼200 gas-phased molecules through their rotational and vibrational transitions. Many classes of organic molecules are represented in this list, including some precursors to biological molecules. A number of unidentified spectral phenomena observed in the interstellar medium are likely to have originated from complex organics. The observations of these features in distant galaxies suggests that organic synthesis had already taken place during the early epochs of the Universe. In the Solar System, almost all biologically relevant molecules can be found in the soluble component of carbonaceous meteorites. Complex organics of mixed aromatic and aliphatic structures are present in the insoluble component of meteorites. Hydrocarbons cover much of the surface of the planetary satellite Titan and complex organics are found in comets and interplanetary dust particles. The possibility that the early Solar System, or even the early Earth, have been enriched by interstellar organics is discussed.

The structure of coronene cluster ions inferred from H2 uptake in the gas phase

“…3a. However, we note that a theoretical study by Rodriguez-Cantano et al that includes quantum effects finds enhanced stability for Ar 6 Cor and Kr 6 Cor but not Ne 6 Cor. 42 The trio of anomalies in the abundance of (H 2 ) n HCor + at n = 32, 36, and 38 is reminiscent of a trio of anomalies in the abundance of He n Cor + at n = 38, 41 and 44, 36 reproduced in Fig.…”

“…60 Adsorption on top of one of the six inner (i) hexagonal rings is about 10% weaker than at c. 8,58 The total energy for adsorbing more than one H 2 is approximately additive provided the molecules do not occupy adjacent hexagonal rings in which case their interaction would be strongly repulsive. 8 (H 2 ) 6 Cor with its alternating occupation of i-sites on both sides of the molecular plane (symmetry C 3v ) seems to be particularly stable, 8 providing a possible rationale for the enhanced abundance of (H 2 ) 6 HCor + , see Fig. 3a.…”

“…Interest in polycyclic aromatic hydrocarbons (PAHs) has many roots, including their role in the formation of soot, 1 of H 2 in the interstellar medium, [2][3][4] as well as their contribution to the diffuse interstellar bands and aromatic infrared bands. [4][5][6] The highly symmetrical, planar coronene molecule (C 24 H 12 , D 6h symmetry) is a strong candidate for many unidentified interstellar bands. 7 It has also served to model adsorption on graphite and graphene, and intercalation within bilayers of graphene which has ramifications for catalysis, efficient storage of molecular gases, and sensing applications.…”

Spitzer’s perspective of polycyclic aromatic hydrocarbons in galaxies

“…velopment of organic life, the detection of PAHs in the early Universe has important astrobiological implications 76,77 .…”

Interstellar Carbon Dust

“…The observations are compared to experiments conducted for identification and interpretation of these astronomical spectra. The several observed forms of carbon in space include (nano-)diamonds, fullerenes, polyaromatic structures, amorphous carbon and their hydrogenated amorphous carbon forms (generally named HAC in astrophysics and a-C:H in physics), as well as by extension the organic matter that originates from the energetic processing of ice mantles in dense cloud regions of the Galaxy and/or from the possible condensation in dense and chemically-rich stellar wind around evolved stars [1,2]. These dust grains are immersed in harsh astrophysical environments including vacuum ultraviolet photons and high energy accelerated particles (the cosmic rays), thermal evolution and will thus be processed.…”