The Laboratory Spectroscopy aims at the collection of new spectroscopic information for potential Complex Organic Molecules (COMs) in view of assigning unidentified signals as well as a deeper characterization of astronomical molecules.
The Laboratory Chemistry aims at supporting the Laboratory Spectroscopy for the characterization of exotic astronomical molecules.
The Astronomical Observations aim at the detection of “new” COMs in the ISM as well as at a thorough mapping of the chemicals present in the ISM and planetary atmospheres.
The Astronomical Modeling aims at inferring the physical structure of the proto-stellar sources to derive COMs abundances.
The Astrochemical Reactivity aims at the investigation of possible reaction pathways leading to the formation of COMs in interstellar molecular clouds.
The Photochemistry aims at the collection of new information for efficient pathways to chemical complexity in space.
The Chemical Evolution aims at unveiling the chemical and physical processes involved in the evolution from molecules through nanoparticles to grains.
Research lines and challenges
1) Unveiling the origin of prebiotic molecules
Two alternative theories for the emergence of life on Earth have been suggested so far: (1) endogenous and (2) exogenous synthesis. In the first theory (1), the synthesis of simple organic molecules having a potential relation to the origin of life occurred directly on our planet starting from simple parent molecules in the atmosphere, liquid water and various energy sources. The Urey-Miller experiment was a milestone in this theory. In the exogenous theory (2), prebiotic molecules came from space, the carriers being comets, asteroids and meteorites. The rationale behind this suggestion is that plenty of complex organic molecules have been observed in interstellar clouds. In the context of the endogenous theory (1), Titan (the largest moon of Saturn) has been postulated to represent a model of primitive Earth. Therefore, the organic chemistry in Titan’s atmosphere is intimately linked to prebiotic organic synthesis in the atmosphere of our primitive planet. On the other hand, in the frame of the exogenous theory (2), it is of fundamental importance not only to discover prebiotic species in space, but also to understand how they could be produced in the typical harsh conditions (extremely low temperature and density) of the ISM.
Recent measurements by the Cassini Mass Spectrometers indicate the presence of numerous large carbocations and carbanions in Titan’s upper atmosphere. Their structure, their potential prebiotic role and plausible reaction routes need to be elucidated.
Several prebiotic molecules have been detected in the gas phase of various regions of the interstellar medium. However, there are still difficulties in elucidating their formation routes and, as a consequence, current chemical models show large deficiencies.
2) Chemical evolution toward the origin of life
In any event, whether they were delivered to Earth from space or synthesized from simpler building blocks, prebiotic molecules then evolved to form more complex molecules. An important example is formamide (NH2CHO), a ubiquitous molecule in the universe that has been detected in many sources throughout the universe. Formamide is a central compound to connect metabolism (conversion of energy), ruled by proteins, and genetics (passage of information), ruled by DNA and RNA. Formamide can indeed polymerize through biocatalyzed processes to provide all five nucleobases of DNA and RNA as well as carboxylic and amino acids. Structurally complex nucleosides and a variety of other biologically relevant molecules can be synthesized from formamide from proton irradiation, which mimics the effect of solar wind.
Minerals may have played a pivotal role in the prebiotic evolution of chemical organic systems mediating the effects of electromagnetic radiation, catalyzing reactions, influencing photostability and/or protecting molecules from degradation.
Self-organization processes can spontaneously occur in organic systems and can facilitate the synthesis of biomolecules.
3) Search of biosignatures toward life detection
The signatures of life (biosignatures) are extremely diverse and may be related either to living organisms or to the remains of extinct organisms. Among them, of particular relevance are the signatures of chiral COMs and gases related to biological metabolisms, such as oxygen, methane and carbon dioxide. Concerning the latter, a particular interest lies in (exo)planetary atmospheres, with remote sensing to be done from ground or from space. Biosignatures are thus determined via (atmospheric) spectroscopy.
Research activities are needed to elucidate the environmental impact on biosignatures: effect of UV radiation from stars and/or high temperatures, photochemistry affecting biosignatures, chemical reactivity in different atmospheric compositions, and so on.