In the interstellar medium, formic acid (HCOOH) plays a significant role in the synthesis of the simplest amino acid, glycine (NH$_{2}$CH$_{2}$COOH). The presence of HCOOH suggests that oxygen-bearing molecules may be directly involved in the chemical and physical evolution of star formation regions, particularly in hot molecular cores. This paper presents the first detection of the rotational emission lines of the $trans$-conformer of HCOOH toward the hot molecular core G358.93$-$0.03 MM1, located in the massive star formation region G358.93$-$0.03. This study employed high-resolution observations from the Atacama Large Millimeter/submillimeter Array (ALMA) in Band 7. The column density and excitation temperature of $t$-HCOOH are determined as $(8.13\pm0.72)\times10^{15}$ cm$^{-2}$ and $120\pm15$ K, respectively. The fractional abundance of $t$-HCOOH relative to H$_{2}$ is $(2.62\pm 0.29)\times 10^{-9}$. The column density ratios of $t$-HCOOH/CH$_{3}$OH and $t$-HCOOH/H$_{2}$CO are $(1.56 \pm 0.12)\times 10^{-2}$ and $(1.16 \pm 0.12)$, respectively. We computed a three-phase warm-up chemical model of HCOOH using the gas-grain chemical code UCLCHEM. We found that the observed and modelled abundances of HCOOH are almost identical, within a factor of 0.89. Based on chemical modelling, we showed that HCOOH may be formed through the reaction between HCO and OH on the grain surface, which is further released in the gas-phase.
The isomerism of molecules in the interstellar medium and the mechanisms behind it are essential questions in the chemistry of organic molecules in space. In particular, for the simple formic and thioformic acids, the low temperatures found in molecular clouds indicate that cis-trans isomerization in the gas-phase must be impeded. Reactions happening on top of interstellar dust grains may explain the isomer interconversion at low temperatures. We studied the isomerization processes of formic and thioformic acid susceptible to happen on the surface of interstellar dust grains and initiated by H…
We studied theoretically the cis-trans isomerization reactions of two astrophysically relevant acids, formic acid (HCOOH) and thioformic acid (HC(O)SH), where the latter has recently been discovered in space. We also searched for these molecules towards the hot core G31.41+0.31 to compare their abundances with the expected theoretical isomerization results. Our results demonstrate that these isomerizations are viable in the conditions of the ISM due to ground-state tunneling effects, which allow the system to reach the thermodynamic equilibrium at moderately low temperatures. At very low tempe…
Cold gas-phase water has recently been detected in a cold dark cloud, Barnard 5 located in the Perseus complex, by targeting methanol peaks as signposts for ice mantle evaporation. Observed morphology and abundances of methanol and water are consistent with a transient non-thermal evaporation process only affecting the outermost ice mantle layers, possibly triggering a more complex chemistry. We present the detection of the Complex Organic Molecules (COMs) acetaldehyde and methyl formate as well as formic acid and ketene, and the tentative detection of di-methyl ether towards the methanol hots…
Thioformic acid (TFA) is the sulfur analog of formic acid, the simplest organic acid. It has three analogues HCOSH, HCSOH, and HCSSH, each of them having two rotational isomeric (rotameric) forms: trans and cis where the trans form is energetically more stable. In this article, we study computational energetics and anharmonic vibrational spectrum of TFA including overtone and combination vibrations. We also studied experimental photoisomerization and photodecomposition channels of HCOSH molecules with different wavelengths. We suggest that TFA is a potential sulfur containing candidate molecul…
Extraterrestrial amino acids, the chemical building blocks of the biopolymers that comprise life as we know it on Earth are present in meteoritic samples. More recently, glycine (NH$_2$CH$_2$COOH), the simplest amino acid, was detected by the Rosetta mission in comet 67P. Despite these exciting discoveries, our understanding of the chemical and physical pathways to the formation of (pre)biotic molecules is woefully incomplete. This is largely because our knowledge of chemical inventories during the different stages of star and planet formation is incomplete. It is therefore imperative to solid…
Investigating how formamide forms in the interstellar medium is a hot topic in astrochemistry, which can contribute to our understanding of the origin of life on Earth. We have constructed a QM/MM model to simulate the hydrogenation of isocyanic acid on amorphous solid water surfaces to form formamide. The binding energy of HNCO on the ASW surface varies significantly between different binding sites, we found values between $\sim$0 and 100 kJ mol$^{-1}$. The barrier for the hydrogenation reaction is almost independent of the binding energy, though. We calculated tunneling rate constants of H +…
Phosphorus is a crucial element in prebiotic chemistry, especially the P$-$O bond, which is key for the formation of the backbone of the deoxyribonucleic acid. So far, PO had only been detected towards the envelope of evolved stars, and never towards star-forming regions. We report the first detection of PO towards two massive star-forming regions, W51 e1/e2 and W3(OH), using data from the IRAM 30m telescope. PN has also been detected towards the two regions. The abundance ratio PO/PN is 1.8 and 3 for W51 and W3(OH), respectively. Our chemical model indicates that the two molecules are chemica…
The formation of asteroids, comets and planets occurs in the interior of protoplanetary disks during the early phase of star formation. Consequently, the chemical composition of the disk might shape the properties of the emerging planetary system. In this context, it is crucial to understand whether and what organic molecules are synthesized in the disk. In this Letter, we report the first detection of formic acid (HCOOH) towards the TW Hydrae protoplanetary disk. The observations of the trans-HCOOH 6$_{(1,6)-5(1,5)}$ transition were carried out at 129~GHz with ALMA. We measured a disk-average…
It has recently been suggested that chemical processing can shape the spatial distributions of complex molecules in the Orion-KL region and lead to the nitrogen-oxygen "chemical differentiation" seen in previous observations of this source. Orion-KL is a very dynamic region, and it is therefore also possible that physical conditions can shape the molecular distributions in this source. Only high spatial resolution observations can provide the information needed to disentangle these effects. Here we present millimeter imaging studies of Orion-KL at various beam sizes using the Combined Array fo…
Phosphorus is a crucial element in biochemistry, especially the P-O bond, which is key for the formation of the backbone of the deoxyribonucleic acid. So far, PO has only been detected towards the envelope of evolved stars, and never towards star-forming regions. We report the first detections of PO towards two massive star-forming regions, W51 e1/e2 and W3(OH), using data from the IRAM 30m telescope. PN has also been detected towards the two regions. The abundance ratio PO/PN is 1.8 and 3 for W51 and W3(OH), respectively. Our chemical model indicates that the two molecules are chemically rela…
The chemical compounds carrying the thiol group (-SH) have been considered essential in recent prebiotic studies regarding the polymerization of amino acids. We have searched for this kind of compounds toward the Galactic Centre quiescent cloud G+0.693-0.027. We report the first detection in the interstellar space of the trans-isomer of monothioformic acid (t-HC(O)SH) with an abundance of $\sim\,$1$\,\times\,$10$^{-10}$. Additionally, we provide a solid confirmation of the gauche isomer of ethyl mercaptan (g-C$_2$H$_5$SH) with an abundance of $\sim\,$3$\,\times\,$10$^{-10}$, and we also detect…
Isocyanic acid (HNCO) is a simple molecule with a potential to form prebiotic and complex organic species. Using a spectral survey collected with the Atacama Pathfinder EXperiment (APEX), in this work we report the detection of 42 transitions of HNCO in the hot molecular core/outflow G331.512-0.103 (hereafter G331). The spectral lines were observed in the frequency interval $\sim$ 160 - 355 GHz. By means of Local Thermodynamic Equilibrium (LTE) analyses, applying the rotational diagram method, we studied the excitation conditions of HNCO. The excitation temperature and column density are estim…
The detection of the amino acid glycine and its amine precursor methylamine on the comet 67P/Churyumov-Gerasimenko by the Rosetta mission provides strong evidence for a cosmic origin of prebiotics on Earth. How and when such complex organic molecules form along the process of star- and planet-formation remains debated. We report the first laboratory detection of glycine formed in the solid phase through atom and radical-radical addition surface reactions under cold dense interstellar cloud conditions. Our experiments, supported by astrochemical models, suggest that glycine forms without the ne…
In the past decade, Astrochemistry has witnessed an impressive increase in the number of detections of complex organic molecules. Some of these species are of prebiotic interest such as glycolaldehyde, the simplest sugar, or amino acetonitrile, a possible precursor of glycine. Recently, we have reported the detection of two new nitrogen-bearing complex organics, glycolonitrile and Z-cyanomethanimine, known to be intermediate species in the formation process of ribonucleotides within theories of a primordial ribonucleic acid (RNA)-world for the origin of life. In this paper, we present deep and…
The low-frequency sky may reveal some of the secrets yet to be discovered and until recently, molecules had never been detected within interstellar clouds at frequencies below 700MHz (Lovas, 2003) . Following the pilot survey towards the Galactic Centre at 103--133MHz with the Murchison Widefield Array (Tremblay, 2017), we surveyed 400 degree squared centered on the Orion KL nebula from 99--170MHz. Orion is a nearby region of active star formation and known to be a chemically rich environment. In this paper, we present tentative detections of nitric oxide and its isotopologues, singularly deut…
Formamide (NH$_2$CHO) has previously been detected in several star-forming regions and is thought to be a precursor for different prebiotic molecules. Its formation mechanism is still debated, however. Observations of formamide, related species and their isopotologues may provide useful clues to the chemical pathways leading to their formation. The Protostellar Interferometric Line Survey (PILS) represents an unbiased high angular resolution and sensitivity spectral survey of the low-mass protostellar binary IRAS 16293-2422 with the Atacama Large Millimeter/submillimeter Array (ALMA). We detec…
Amino acids are the essential keys that contribute to the study of the formation of life. The simplest amino acid, glycine (NH$_{2}$CH$_{2}$COOH), has been searched for a long time in the interstellar medium, but all surveys of glycine have failed. Since the detection of glycine in the interstellar medium was extremely difficult, we aimed to search for the precursor of glycine. After detailed searches of the individual prebiotic molecular species, we successfully identified the emission lines of possible glycine precursor molecule amino acetonitrile (NH$_{2}$CH$_{2}$CN) towards the hot molecul…
We report on a systematic search for oxygen-bearing Complex Organic Molecules (COMs) in the Solar-like protostellar shock region L1157-B1, as part of the IRAM Large Program "Astrochemical Surveys At IRAM" (ASAI). Several COMs are unambiguously detected, some for the first time, such as ketene H$_2$CCO, dimethyl ether (CH$_3$OCH$_3$) and glycolaldehyde (HCOCH$_2$OH), and others firmly confirmed, such as formic acid (HCOOH) and ethanol (C$_2$H$_5$OH). Thanks to the high sensitivity of the observations and full coverage of the 1, 2 and 3mm wavelength bands, we detected numerous (10--125) lines fr…
An interstellar energetic and non-aqueous pathway to peptide formation
Aarhus University（奥胡斯大学）；Queen Mary University of London（伦敦大学玛丽女王学院）；HUN-REN Institute for Nuclear Research (Atomki)（匈牙利研究与教育网络核研究所）；University of Debrecen（德布勒森大学）；Queen’s University Belfast（贝尔法斯特女王大学）
The interstellar medium is characterized by a rich and diverse chemistry. Many of its complex organic molecules are proposed to form through radical chemistry in icy grain mantles. Radicals form readily when interstellar ices (composed of water and other volatiles) are exposed to UV photons and other sources of dissociative radiation, and, if sufficiently mobile, the radicals can react to form larger, more complex molecules. The resulting complex organic molecules (COMs) accompany star and planet formation, and may eventually seed the origins of life on nascent planets. Experiments of increasi…
Chemical models and experiments indicate that interstellar dust grains and their ice mantles play an important role in the production of complex organic molecules (COMs). To date, the most complex solid-phase molecule detected with certainty in the ISM is methanol, but the James Webb Space Telescope (JWST) may be able to identify still larger organic species. In this study, we use a coupled chemo-dynamical model to predict new candidate species for JWST detection toward the young star-forming core Cha-MMS1, combining the gas-grain chemical kinetic code MAGICKAL with a 1-D radiative hydrodynami…
Here we present high spatial resolution (<1 arcsecond) observations of molecular emission in Orion-KL conducted using the Combined Array for Research in Millimeter-Wave Astronomy (CARMA). This work was motivated by recent millimeter continuum imaging studies of this region conducted at a similarly high spatial resolution, which revealed that the bulk of the emission arises from numerous compact sources, rather than the larger-scale extended structures typically associated with the Orion Hot Core and Compact Ridge. Given that the spatial extent of molecular emission greatly affects the determin…
Frontiers of chemical complexity in the interstellar medium: unveiling the cosmic origins of life
Centro de Astrobiología (CAB), CSIC-INTA（天体生物学中心（CAB），西班牙国家研究委员会-国家航空航天技术研究所）；INAF-Osservatorio Astrofisico di Arcetri（意大利天文台协会阿切尔蒂天文台）；Niels Bohr Institute（尼尔斯·玻尔研究所）；University of Bordeaux（波尔多大学）；DCBP, Universität Bern（伯尔尼大学）；Univ. Grenoble Alpes（格勒诺布尔阿尔卑斯大学）；LUX, Observatoire de Paris, CNRS（巴黎天文台，法国国家科学研究中心）；ESO/JAO（欧洲南方天文台/联合天文办公室）；Univ. Toulouse, CNRS, IRAP（图卢兹大学，法国国家科学研究中心，天体物理学研究所在）；University of Sevilla（塞维利亚大学）；University of Lincoln（林肯大学）；UK Astronomy Technology Centre（英国天文技术中心）；ESO（欧洲南方天文台）；ICE-CSIC（空间科学与地球化学研究所，西班牙国家研究委员会）；Jodrell Bank Centre for Astrophysics, The University of Manchester（曼彻斯特大学乔德雷尔银行天体物理学中心）；University of Cologne（科隆大学）；RIKEN Pioneering Research Institute（理化学研究所前沿研究机构）；Univ. Florida（佛罗里达大学）；Massachusetts Institute of Technology（麻省理工学院）；Chinese Academy of Sciences South America Center for Ast（中国科学院南美天文中心）
We present the first census of the interstellar Complex Organic Molecules (iCOMs) in the low-mass Class I protostar SVS13-A, obtained by analysing data from the IRAM-30m Large Project ASAI (Astrochemical Surveys At IRAM). They consist of an high-sensitivity unbiased spectral survey at the 1mm, 2mm and 3mm IRAM bands. We detected five iCOMs: acetaldehyde (CH$_3$CHO), methyl formate (HCOOCH$_3$), dimethyl ether (CH$_3$OCH$_3$), ethanol (CH$_3$CH$_2$OH) and formamide (NH$_2$CHO). In addition we searched for other iCOMs and ketene (H$_2$CCO), formic acid (HCOOH) and methoxy (CH$_3$O), whose only k…
