ACO · AstroChemical Origins

AstroChemical Origins

Thousands of exoplanets have been found in the Milky Way since the first discovered by the Nobel laureates Mayor and Queloz in 1995. Yet, none of the so far known planetary systems resembles to our own Solar System. Nature has, clearly, thousands of ways to form a star and a surrounding planetary system and the question is: Which path did the Solar System follow? Tightly associated to that, another basic question arises: Did the history of the Solar System formation facilitate or even trigger the emergence of life on Earth? Since human memory, humankind has been asking similar questions that can be summarized in one single big one: What are our origins? The ACO (Astro-Chemical Origins) project had the ambitious ultimate goal to discover the link between the interstellar chemistry and the one responsible of the chemical composition of the Solar System bodies: in other words, ACO goal is to understand our astro-chemical origins (see attached figure). The project is split in five major objectives. Together, they better characterize the chemical composition of the planetary systems forming nowadays in the Milky Way, to understand their variety and its origin and, ultimately, to identify the path followed by the Solar System by comparing its chemical properties with the systems that now in their early evolution. The project is organized in four Work Packages (WPs), whose specific objectives are: 1) Improve the detection capabilities; 2) Set up a large database of observations 3) Understand the astrochemical processes 4) Develop astrochemical models and tools, and a new Proto Solar nebula model. Seventeen Early Stage Researchers (ESRs) have been recruited on the project to carry out the work to reach the objectives of each WP and, along with that, the overall ACO goal. All the objectives have been reached. Specifically, we designed and manufactured a new cryogenic receiver at 22 GHz with a gain between 10 and 20 dB and tuneable by applying an external magnetic field. We built a huge data base of homogeneous data from four Large Programs led by ACO members on different millimetre to Far-Infrared telescopes: Herschel/CHESS, IRAM-30m/ASAI and NOEMA/SOLIS. The inclusion of a fourth dataset based on ALMA/FAUST is in progress. The exploitation of those databases has allowed us to discover many new aspects of the solar-like star formation and their dependence on the environment. We carried out several experimental and theoretical studies that have allowed to drastically improve the reliability and content of the gas-phase and surface reaction networks and processes, with several “first ever” achievements: experimental and theoretical studies of the most exotic and poorly understood though crucial gas-phase reactions between neutral atoms and ions with large molecules, and novel and multifaceted theoretical and experimental studies of how molecules stick on the interstellar iced grains, diffuse and react, all poorly known but crucial processes in the growth of the interstellar molecular complexity. We included new processes in existing astrochemical models, sensibly improving their capacity to describe the astrophysical and astrochemical processes occurring during the solar-like star formation. We developed new tools to extract the information from observations compared to model predictions. We produced a new gas-phase network and a new model of how water is distributed in an analogue of the Proto-Solar Nebula. Harmed with all these new knowledge and tools, we are closer to understand the astrochemical origin of the Solar System and the path through which the initial clump of diffuse material became a system of planets, and life emerged on Earth.

Data: CORDIS, © European Union