Until recently, it was thought that the production of larger interstellar molecules proceeds by definite chemistries depending upon the physical conditions of the source. For cold and pre-stellar cores at 10 K, it was thought that ion-molecule processes dominate the large molecule chemistry and lead to the production of very unsaturated carbon-chain type species. For hot cores, it was...
The high-mass star-forming core G31.41+0.31 is one of the most chemically rich hot molecular cores in the Galaxy. In particular, the first detection outside the Galactic Center of the simplest sugar-like species, glycolaldehyde, has been obtained towards G31, and heavy complex molecules such as methyl formate, ethanol or ethylene glycol have also been observed. The chemical complexity of this...
Cyanopolyynes are carbon chains delimited at their two extremities by an atom of hydrogen and a cyano group, hence they could be excellent reservoirs of carbon. The simplest member, HC3N, is ubiquitous in the galactic interstellar medium, and it is detected also in external galaxies. Because of their potential to form (macro-)molecules of biogenic importance, understanding the growth of...
In the last 50 years of astrochemical research, the realm of one-dimensional carbon chemistry (i.e. carbon chain molecules) has been well explored. Life, however, relies on two and three-dimensional carbon - branches, rings, bridges, and so forth. Here, we present the first rotational detection of a six-membered ring molecule in the interstellar medium (ISM), benzonitrile (c-C$_6$H$_5$CN),...
Pre-stellar cores represent the initial conditions of Solar-system formation. In the past, these gravitationally collapsing condensations were believed to present a simple chemistry characterised by severe freezing-out of carbon-bearing species in their densest and coldest, innermost regions. However, thanks to the advent of higher-sensitivity instrumentation, it has become clear that...
The role of the pre-solar chemistry in the present chemical composition of the Solar System bodies is far to be understood. The molecular complexity builds up at each step of the process leading to star formation, starting from simple molecules and ending up in interstellar Complex Organic Molecules (iCOMs). It is of paramount importance to image the spatial distribution of iCOMs in order to...
Abstract
Comets are thought to contain relatively pristine material from the origin of the solar system, having condensed directly out of the pre-solar nebula (e.g., Mumma & Charnley 2011). It is postulated that comets may have even delivered some of the water and organic matter found on the Earth via impacts (e.g., Hartogh et al. 2011). Over 22 molecules have been identified in...
Complex molecules are commonly detected in high- and low-mass star
forming regions. In the past years, however, complex species have been
detected in unexpected environments like photo-dominated regions
(PDRs). The great sensitivity and resolution power of ALMA has also
allowed us to start detecting and resolving complex species in
protopanetary disks.
I will show recent observations...
The harsh radiation environment of disk surfaces is thought to be inhospitable to organic molecules. Indeed, the disk surface is sweltering atomic gas of several thousand Kelvin, well in excess of the dust temperature. However, as radiation is shielded by increasing column densities of dust the potential for molecules to form increases as both the photodissociation rates and temperatures...
Complex organic molecules are detected in gas and solid phases of astrophysical objects. The origin of these molecules is still debated, but a large part is supposed to form at the surface of astrophysical icy grains. These icy grains that can be observed in dense molecular clouds are processed under high energetic processes (VUV photons, ions, electrons) during the star formation. Processing...
Comet 67P/Churyumov–Gerasimenko has been studied with unique in situ measurements by various instruments aboard the Rosetta spacecraft. Data from ROSINA, COSAC, VIRTIS and MIRO have shown that the comet has a rich molecular inventory and that there is a complex relationship between production rates and correlations between various species. The currently available data on 67P/C-G is one of the...
The landing of the ROSETTA module Philae in 2014 kicked up a lot of dust, figuratively as well as literally. The not-quite-as-planned landing displaced about 0.4 m3 of dust[1], some of which ended up in the COSAC instrument[2], where it warmed to around 20°C, releasing its volatiles. Although the COSAC instrument could never play out its full potential, it did...
Simple and complex species are expected to be formed in a variety of interstellar environments at the surface of ice grains by means of a combination of processes. Interstellar ice mantles are continuously exposed to energetic and non-energetic processing by photons, electrons, ions and atoms in different regions of the interstellar medium. Here I will focus on the chemical role of electrons...
The icy worlds in our Solar System (e.g. Europa, Enceladus, Ceres, Triton and Titan) possess surface organics, and possibly subsurface oceans, so are prime astrobiological targets in the search for Life. Space missions to these icy worlds have been the key to measuring their surface composition and assessing their subsurface composition through measurements of their outgassing plumes....
Phosphorus (P) is a key chemical biogenic element for the development of life[1,2,3,4], because P-compounds are unique to form large biomolecules such as deoxyribonucleic acid (DNA) and ribonucleic acid (RNA), phospholipids (the structural components of all cellular membranes) and the adenosine triphosphate (ATP) molecule, from which all forms of life assume energy. Despite the critical...
In our laboratory we are currently bringing a new UHV setup to production. We will present this setup which enables us to reach conditions similar to those present in dense molecular clouds (T = 10 K, ρN = 105 cm-3). In combination with our laser ablation setup, which we use to produce realistic carbonaecous and silicate dust analoga, we will use the UHV setup to study the chemical...
The TMC-1 Molecular Cloud in Taurus has been used as astrochemical laboratory to test new approaches in computational chemistry to predict molecular abundances in interstellar space. TMC-1 has been observed to contain a large variety of complex molecules such as acids, alcohols and hydrocarbons. In the laboratory, the synthesis of such prebiotic molecules has been confirmed to occur when...
Formamide has been detected in many stellar and interstellar objects like the comet C/1995 O1 (Hale-Bopp),1 in the solid phase of dust grains around the young stellar object W33A2 and in the interstellar medium in general3. Formamide is proposed to be a key-molecule in the abiotic formation of important biomolecules4 and may be brought to planet...
The formation of methanol (CH3OH) on icy grains in cold interstellar clouds is generally related to hydrogenation reactions during the catastrophic CO freeze–out stage. This explains why CO and CH3OH are mixed in interstellar ices. Yet there are reasons to believe that CH3OH can also form at an earlier period of interstellar ice evolution in CO–poor and H2O–rich ices. Here we present a...
There is a growing evidence that our Sun was born in a rich cluster that also contained massive stars (Adams, 2010; Taquet et al. 2016). Therefore, the study of the chemical content and chemical processes (such as fractionation) in high-mass star-forming regions is key to understand our chemical heritage. We are thus undertaking a huge observational effort to derive the $^{14}$N/$^{15}$N...
Phosphorus is one of the crucial elements for life. It plays a central role in the structure of essential biotic molecules, such as nucleic acids (DNA and RNA), phospholipids (the skin of all cellular membranes) and the adenosine triphosphate (ATP), from which all forms of life assume energy (Pasek & Lauretta 2005).
Despite its importance, the chemistry of Phosphorus in the interstellar...
The simplest amino acid, glycine, has recently been identified on the comet Churyumov–Gerasimenko (67P) [Altwegg et al., 2016]. Independent on how this and likely other amino acids have been formed - in-situ or inherited along the different chemical stages during comet formation in the Solar Nebula - the ice embedded amino acids have been exposed to radiation, including vacuum ultraviolet...
Hot cores are ideal laboratories for the formation of complex organic molecules. Here, we present a detailed observational and modeling study of the chemistry in the prototypical hot core region AFGL 2591. It evolves in unique conditions being isolated from other young OB stars with strong UV radiation. This region is part of the NOEMA (Northern Extended Millimeter Array) large program CORE...
Many chemical reactions occur at the surface of interstellar dust grains, producing a large diversity of molecules more or less complex. Most current astrochemical models include only a single size of grains (0.1 micron representing most of the mass of silicate grains) to study the formation and destruction of molecules on the dust surface. We have studied the effect of considering a...
An out-of-equilibrium physical environment can drive chemical reactions into thermodynamically unfavorable regimes. Under prebiotic conditions such a coupling between physical and chemical non-equilibria may have enabled the spontaneous emergence of primitive evolutionary processes. Here, we study the coupling efficiency within a theoretical model that is inspired by recent laboratory...
Protostellar envelopes are usually approximated as spherical dense and cold regions around early-type stars during the initial phases of star formation. Such regions can harbour volatile and non-volatile astrophysical ices with desorption temperatures between 20 – 150 K. However, little is known about the role of external irradiation for the survival of ices in protostellar envelopes. In...
Many interstellar molecules are known to have essential functions in terrestrial biochemistry. Observations of prebiotically important COMs thus enable us to better understand the origin of primitive organic materials found in our Solar System. Glycine and pyrimidine, the simplest amino acid and the building blocks of nucleic acid, respectively, were both detected in meteorites and comets....
Extraterrestrial ices are observed in many astrophysical environments linked to the formation of stars and planetary systems but also disks and various debris such as comets and asteroids. The chemical evolution of these ices following photo- and thermo-chemistry is routinely simulated in the laboratory. These simulations always end with the building up and recovery at room temperature, of...
Life is a non-equilibrium system, which is nowadays maintained by a highly developed energy conversion machinery. Four billion years ago, other non-equilibrium mechanisms were needed to kick-start living processes. We propose ubiquitous heat fluxes as suitable driving force: Thermal gradients across water filled pores lead to a concurrent fluid convection and directed movement of dissolved...
One of the most fundamental questions for humanity is how life emerge on Earth and in this context how were the first prebiotic organic compounds formed and distributed. Therefore it is necessary to find and investigate environmental archives that retained information from the early Earth.
The analysis of fluid iclusions (FIs) is a widely used geochemical tool to determine thermobaric and...
Despite a rather low elemental abundance of $\sim 3\times 10^{-7}$ (Asplund et al. 2009), Phosphorus is one of the main biogenic elements, present in all life forms on Earth. As such, phosphorus-bearing compounds, in particular their P--O bonds, play a key role in many biochemical and metabolic processes in living systems. However, Phosphorus chemistry in the interstellar medium has received...
The question of how life could have arisen from non-living molecular systems is not only fundamentally and philosophically interesting, but it requires us to closely examine the common features of life as we know it, and to imagine the possibilities for life as we do not know it. While much progress has been made elucidating possible chemical systems as candidates for early pre-biological...
The question of the formation of Complex Organic Molecules (COMs) in ISM is a main issue in the field of prebiotic chemistry. More particularly, glycolaldehyde is an important species in this context, especially because it is the simplest sugar-related compound. Indeed, it is thought to be able to be converted into short dipeptides[1] or amino acids[2] and to ease the formation of more complex...
Computational approaches are nowadays a full, self-standing branch of chemistry, both for their quantum-based (“ab initio”) accuracy, and for its multiscale extent. In prebiotic chemistry, however, due to the instrinsic complexity of the chemical problems, ab initio atomistic simulations have so far had a limited impact, with the exception of a few relevant studies. Surprisingly, even the...
Understanding the interaction between biomolecules, such as amino-acids, peptides or proteins, and surfaces is of importance in the fields of surface chemistry, catalysis and prebiotic chemistry. It has been found that a number of amino-acids self-organize to form well-ordered two-dimensional structures at metal surfaces (1). On the other hand, it is important to explore the role-play by...
One major unresolved question in the origin of life is the autonomous synthesis of nucleotides. Recent chemical advances have thrown light upon potential synthetic pathways for the production of nucleotides in the laboratory, starting from simple precursors [1]. However, so far the original experiments were performed in bulk chemistry, and the synthetic steps successively one by one,...
The origins of life on Earth is postulated to have begun with simple organic molecules. A plausible source of such prebiotic molecules is the interstellar medium (ISM). Therefore, the search for complex organic molecules (COMs, containing C and more than 6 atoms) especially nitrogen-bearing prebiotic molecules in the ISM has opened the possibility of understanding how life could emerge on...
Shocks are a crucial probe to understanding the ongoing chemistry within ices on interstellar dust grains, where many complex organic molecules (COMs) are believed to be formed. However, previous theoretical work has been limited to the initial liberation into the gas-phase through non-thermal desorption processes such as sputtering. Here, we present results from an adaptation of the...
Most stars, including our Sun, form in clusters embedded within molecular clouds. It is then important to characterize their formation in dense environments and to asses whether the environments play a role in the subsequent evolution, specially whether planet formation is altered with respect to the more isolated stars formed in dark clouds.
We present ALMA observations at 1.1. mm with an...
Protoplanetary discs are one of the most extreme environments in astrophysics, spanning a huge range of temperatures and densities. As such, modelling their chemical evolution is challenging, and has often been reduced to the study of 2-dimensional, axisymmetric discs. However, the advent of ALMA has shown that many protoplanetary discs do not conform to this axisymmetry. In particular, the...
