The origin of methane and biomolecules from a CO2 cycle on terrestrial planets

Pietrucci

Saitta

et al. 2019

A&A

Context. It is well known that hydrogen cyanide and formamide can universally be considered as key molecules in prebiotic synthesis. Despite the fact that formamide has been detected in interplanetary and interstellar environments, other prebiotic species are far more abundant, including, for example, formaldehyde. However, several results indicate that formamide can play the role of important intermediate as well as that of a feedstock molecule in chemical abiogenesis. Diverse recently proposed scenarios of the origins of the first biopolymers show that liquid formamide environments could have been crucial for the formation of nucleobases, nucleosides, and for phosphorylation reactions, which lead to nucleotides. Aims. Here we report on a wide exploration of the formaldehyde reaction network under plasma conditions mimicking an asteroid descent in an Earth-like atmosphere and its impact. Methods. Dielectric breakdown using a high-power kJ-class laser system (PALS – Prague Asterix Laser System) along with quantum mechanical, ab initio molecular dynamics, and enhanced sampling simulations have been employed in order to mimic an asteroid impact plasma. Results. Being more abundant than formamide both in interstellar and interplanetary environments, during the era of early and late heavy bombardment of Earth and other planets, formaldehyde might have been delivered on asteroids to young planets. In the presence of nitrogen-bearing species, this molecule has been reprocessed under plasma conditions mimicking the local environment of an impacting body. We show that plasma reprocessing of formaldehyde leads to the formation of several radical and molecular species along with formamide. Conclusion. All the canonical nucleobases, the simplest amino acid (i.e., glycine), and the sugar ribose, have been detected after treatment of formaldehyde and nitrogen gas with dielectric breakdown. Our results, supported by quantum mechanical and enhanced sampling simulations, show that formaldehyde – by producing inter alia formamide – may have had the role of starting substance in prebiotic synthesis.

Section: Introductionmentioning

confidence: 99%

“…Moreover, the environment on early Earth was certainly influenced by the delivery of a wide range of organic substances such as formamide, formaldehyde, and hydrogen cyanide. These compounds might also have played the role either of parent compounds or of intermediates in prebiotic processes (Ferus et al 2017b;Civis et al 2017).…”

Section: Introductionmentioning

confidence: 99%

Prebiotic synthesis initiated in formaldehyde by laser plasma simulating high-velocity impacts

Pietrucci

Saitta

et al. 2019

A&A

“…In the past two decades, our team demonstrated several experiments that mostly focused on the chemical transformations of the atmosphere or on the interaction with solid or liquid surfaces (Babánková et al 2006a). Most studies have been focused on impact-induced synthesis of biomolecules (Šponer et al 2016;Ferus et al 2017b) such as canonical nucleobases in Ferus et al (2012Ferus et al ( , 2014aFerus et al ( ,b, 2015Ferus et al ( , 2017b, sugars in Civiš et al (2016a), and aminoacids in Civiš et al (2004), or the transformation of atmospheric molecules on early terrestrial planets (Civiš et al 2008) such as the formation or decay of prebiotic substances, for instance, formamide (Ferus et al 2011), isocyanic acid (Ferus et al 2018a), and the transformations of hydrogen cyanide (Ferus et al 2017c), acetylene (Civiš et al 2016b), methane (Civiš et al 2017), or carbon monoxide (Civiš et al 2008;Ferus et al 2009). Pyrometric measurement of dielectric breakdown induced by high-power terawatt-class lasers in the gas phase has shown that airglow temperatures of 4500 K (Babánková et al 2006b) are very close to the low-temperature component in meteor spectra that exhibits 3800-6000 K independent of the mass of the impacting body or its velocity (specifically in the ranges of 35 and 72 km s −1 and masses between 1025 g and 1 g, according to Jenniskens et al 2004).…”

Section: Introductionmentioning

confidence: 99%

Main spectral features of meteors studied using a terawatt-class high-power laser

Kubelík

Petera

et al. 2019

A&A

Context. Meteor spectra are commonly interpreted using data from databases and tables. Several studies have demonstrated very sophisticated calculations of elemental compositions of meteoroid bodies based on the computation of synthetic meteor spectra or on the spectral analysis of airglow plasma containing evaporated, atomized, and ionized meteoroid matter. However, considering accuracy, reliability of computations, lack of laboratory experimental data in this field, as well as the complicated physical structure of meteor plasma, such qualitative assignment or quantitative calculations are still extensively discussed in the scientific community. Even on the laboratory level, many studies have shown the high complexity of the acquisition and interpretation of the data that are recorded with techniques of emission spectroscopy that are in fashion and philosophy similar to the spectral analysis of meteor plasma, that is, detection and quantification of the elements that are ablated from complicated multicomponent matrices. Aims. The current study is focused on the application of terawatt-class laser-induced breakdown spectroscopy (TC-LIBS) of real samples of chondritic meteorites. We recorded emission spectra with high resolution and high precision that contain spectral lines that are typical for real meteoric spectra. Experimental data were compiled in a form that is convenient for the meteoric spectra interpretation and calibration. Methods. TC-LIBS was carried out by a high-power terawatt-class laser facility, the Prague Asterix Laser System (PALS). The spectra were simultaneously recorded by an echelle high-resolution spectrograph in the UV/VIS spectral ranges and by a low-resolution spectrograph that was used for real observation of meteor spectra. We also present calculated synthetic spectra based on data from the NIST atomic spectra database. Results. We assembled etalon qualitative tables of major meteoric spectral features that can be used both for the spectral wavelength calibration of low-resolution observational instruments and for the exact interpretation of meteor spectra. The data are compared with real meteor spectra.

“…Besides the traditional HCNand reducing-atmospheres based biomolecules synthesis (Ferris et al 1974;Yuasa et al 1984;Levy et al 1999;Sutherland 2016;Civiš et al 2017), the current evidence shows that the formamide molecule did not necessary play role of merely starting parent prebiotic precursor, but also it could serve as an intermediate compound in prebiotic synthesis (Ferus et al 2017b). In fact, it has been demonstrated that it acted either as substrate or as intermediate in a series of complex reactions starting from very reactive small radicals and leading to a broad palette of biomolecules, for example, all the canonical nucleobases of the genetic code, ribose and other sugars, amino acids or even fatty acids (Saladino et al 2011(Saladino et al , 2015Ferus et al 2015b).…”

Section: Introductionmentioning

confidence: 99%

“…Space radiation effects in both moons, coupled with the Saturn's magnetosphere, could cause a series of events potentially leading to prebiotic chemical evolution. Among the others, the laboratory simulation of atmospheric discharges in the early Earth's atmosphere or in recent Saturn's and Titan's atmosphere, and a simulation of plasma are of particular interest (Hébrard et al 2012;Hoerst et al 2012;Civiš et al 2017;Ferus et al 2017a). …”

Section: Introductionmentioning

confidence: 99%

HNCO-based synthesis of formamide in planetary atmospheres

Laitl

Knížek

et al. 2018

A&A

Time-resolved Fourier transform infrared emission spectroscopy, Fourier transform absorption infrared spectroscopy, and highresolution UV-ViS emission spectroscopy have been used to characterize the chemistry of isocyanic acid (HNCO) under glow discharge conditions in planetary atmospheres. HNCO mixtures (i.e., composed of di-hydrogen or ammonia) have been investigated in order to unveil the possible reaction pathways leading to the synthesis of the key prebiotic molecule formamide (HCONH 2 ), upon planetary atmospheres containing isocyanic acid in presence of di-hydrogen and, separately, of ammonia. In addition, ab initio molecular dynamics simulations coupled with a modern metadynamics technique have been performed in order to identify the most likely chemical pathways connecting HNCO to formamide. It turned out that the direct hydrogenation of HNCO is thermodynamically favored. Incidentally, the experimental results -supplied by a simplified kinetic model -also proved the favorability of the reaction HNCO + H 2 → HCONH 2 which, moreover, spontaneously takes place in unbiased ab initio molecular dynamics simulations carried out under the effect of intense electric fields.