A5091123078- Astrophysics and Star Formation Studies
- Molecular Spectroscopy and Structure
- Atmospheric Ozone and Climate
- Astro and Planetary Science
- Stellar, planetary, and galactic studies
- Advanced Chemical Physics Studies
- Spectroscopy and Laser Applications
- Astronomy and Astrophysical Research
- Astronomical Observations and Instrumentation
- Atmospheric chemistry and aerosols
- Gamma-ray bursts and supernovae
- Spacecraft and Cryogenic Technologies
- Solar and Space Plasma Dynamics
- Atomic and Molecular Physics
- Astrophysics and Cosmic Phenomena
- Galaxies: Formation, Evolution, Phenomena
- Calibration and Measurement Techniques
- Astrophysical Phenomena and Observations
- Inorganic Fluorides and Related Compounds
- nanoparticles nucleation surface interactions
- Ionosphere and magnetosphere dynamics
- Phase Equilibria and Thermodynamics
- Quantum, superfluid, helium dynamics
- SAS software applications and methods
- Catalysis and Oxidation Reactions
Centre National de la Recherche Scientifique
2016-2025
Institut de Planétologie et d'Astrophysique de Grenoble
2016-2025
Université Grenoble Alpes
2016-2025
Roma Tre University
2025
Royal Society of Chemistry
2023
Arcetri Astrophysical Observatory
2016-2022
École Normale Supérieure de Lyon
2022
Carnegie Institution for Science
2022
Geophysical Laboratory
2022
European University of Rome
2022
While warm dense gas is prevalent around low-mass protostars, the presence of complex saturated molecules—the chemical inventory characteristic hot cores—has remained elusive in such environments. Here we report results an IRAM 30 m study molecular composition associated with protostar IRAS 16293-2422. Our observations highlight extremely rich organic this source abundant amounts O- and N-bearing molecules as formic acid, HCOOH, acetaldehyde, CH3CHO, methyl formate, CH3OCHO, dimethyl ether,...
Context. Complex organic molecules (COMs) have long been detected in the interstellar medium, especially hot cores and corinos of low-mass protostars. Their formation routes however remain uncertain. Both warm gas-phase reactions grain-surface invoked to account for their presence In this latter scheme, COMs result from radical-radical on grains as radicals become mobile when nascent protostar warms up its surroundings resulting are subsequently desorbed into gas phase at higher temperatures.
Abstract While astrochemical models are successful in reproducing many of the observed interstellar species, they have been struggling to explain abundances complex organic molecules. Current tend privilege grain surface over gas-phase chemistry their formation. One key assumption those is that radicals trapped mantles gain mobility and react on lukewarm ( ≳ 30 K) dust grains. Thus, recent detections methyl formate (MF) dimethyl ether (DME) cold objects represent a challenge may clarify...
The BASECOL2012 database is a repository of collisional data and web service within the Virtual Atomic Molecular Data Centre (VAMDC, http://www.vamdc.eu). It contains rate coefficients for excitation rotational, ro-vibrational, vibrational, fine, hyperfine levels molecules by atoms, molecules, electrons, as well fine-structure some atoms that are relevant to interstellar circumstellar astrophysical applications. Submissions new published sets welcome, they will be critically evaluated before...
We report the detection of complex molecules (HCOOCH3, HCOOH, and CH3CN), signposts a hot core-like region, toward low-mass Class 0 source NGC 1333 IRAS 4A. This is second protostar in which such have been searched for reported, other being 16293-2422. It therefore likely that compact (a few tens AU) regions dense warm gas, where chemistry dominated by evaporation grain mantles are found, common sources. Given chemical formation timescale much shorter than gas hot-core crossing time, it not...
We report the first detection of doubly-deuterated methanol (CHD2OH), as well firm detections two singly-deuterated isotopomers (CH2DOH and CH3OD), towards solar-type protostar IRAS 16293-2422. From present multifrequency observations, we derive following abundance ratios: , . The total deuterated forms is greater than that its normal hydrogenated counterpart in circumstellar material 16293-2422, a circumstance not previously encountered. Formaldehyde, which thought to be chemical precursor...
We report the first detection of triply-deuterated methanol, with 12 observed transitions, towards low-mass protostar IRAS 16293-2422, as well multifrequency observations 13CH3OH, used to derive column density main isotopomer CH3OH. The derived fractionation ratio [CD3OH]/[CH3OH] averaged on a 10'' beam is 1.4%. Together previous CH2DOH and CHD2OH observations, present CD3OH are consistent formation methanol grain surfaces, if atomic D/H 0.1 0.3 in accreting gas. Such high can be reached...
We report the detection of D2CO in a sample starless dense cores, which we previously measured degree CO depletion. The deuterium fractionation is found to be extremely high, [D2CO]/[H2CO] ~ 1%-10%, similar that reported low-mass protostars. This provides convincing evidence formed cold prestellar cores and later desorbed when gas warms up find with highest depletions have also largest ratios, supporting theoretical prediction deuteration increases increasing
Context. The high degree of deuteration observed in some prestellar cores depends on the ortho-to-para H2 ratio through H3+ fractionation. Aims. We want to constrain ortho/para across L183 core. This is mandatory correctly describe deuter- ation amplification phenomenon depleted such as and relate total (ortho+para) H2D+ abundance sole ortho-H2D+ column density measurement. Methods. To this derive its profile, we make use N2D+ /N2H+ observations performed two simple chemical models limited...
New insights into the formation of interstellar formamide, a species great relevance in prebiotic chemistry, are provided by electronic structure and kinetic calculations for reaction NH2 + H2CO -> NH2CHO H. Contrarily to what previously suggested, this is essentially barrierless can, therefore, occur under low temperature conditions objects thus providing facile route formamide. The rate coefficient parameters channel leading H have been calculated be A = 2.6x10^{-12} cm^3 s^{-1}, beta -2.1...
Complex organic molecules have been observed for decades in the interstellar medium. Some of them might be considered as small bricks macromolecules at base terrestrial life. It is hence particularly important to understand chemistry Solar-like star forming regions. In this article, we present a new observational project: SOLIS (Seeds Of Life Space). This Large Project IRAM-NOEMA interferometer, and its scope image emission several crucial sample regions different evolutionary stage...
Complex organic molecules (COMs) have been detected in a variety of environments including cold prestellar cores. Given the low temperatures these objects, detections challenge existing models. We report here new observations toward core L1544. They are based on an unbiased spectral survey 3 mm band at IRAM 30 m telescope as part Large Program ASAI. The allow us to provide full census oxygen-bearing COMs this source. tricarbon monoxide, methanol, acetaldehyde, formic acid, ketene, and...
Formamide (NH2CHO) has been proposed as a pre-biotic precursor with key role in the emergence of life on Earth. While this molecule observed space, most its detections correspond to high-mass star-forming regions. Motivated by lack investigation low-mass regime, we searched for formamide, well isocyanic acid (HNCO), 10 low- and intermediate-mass pre-stellar protostellar objects. The present work is part IRAM Large Programme ASAI (Astrochemical Surveys At IRAM), which makes use unbiased...
Context. Unbiased spectral surveys are powerful tools to study the chemistry and physics of star forming regions, because they can provide a complete census molecular content observed lines probe physical structure source.
Formamide (NH2CHO), the simplest possible amide, has recently been suggested to be a central species in synthesis of metabolic and genetic molecules, chemical basis life. In this Letter, we report first detection formamide protostar, IRAS 16293−2422, which may similar Sun solar system progenitor. The data combine spectra from millimeter submillimeter TIMASSS survey with recent, more sensitive observations at IRAM 30 m telescope. With an abundance relative H2 ∼10−10, appears as abundant...
Context. Water is a primordial species in the emergence of life, and comets may have brought large fraction to Earth form oceans. To understand evolution water from first stages star formation planets comets, HDO/H2O ratio powerful diagnostic.
Abstract Despite the harsh conditions of interstellar medium, chemistry thrives in it, especially star-forming regions where several complex organic molecules (iCOMs) have been detected. Yet, how these species are synthesized is a mystery. The majority current models claim that this happens on grain surfaces. Nevertheless, evidence mounting neutral gas-phase plays an important role. In paper, we propose new scheme for synthesis glycolaldehyde, with prebiotic potential and which no formation...
ABSTRACT We have analyzed rotational spectral line emission of OCS, CH 3 OH, HCOOCH , and H 2 CS observed toward the low-mass Class 0 protostellar source IRAS 16293–2422 Source A at a sub-arcsecond resolution (∼0.″6 × 0.″5) with ALMA. Significant chemical differentiation is found on scale 50 au. The OCS to trace well infalling–rotating envelope in this source. On other hand, distributions OH are be concentrated around inner part envelope. With simple ballistic model envelope, radius...
The high abundances of Complex Organic Molecules (COMs) with respect to methanol, the most abundant COM, detected towards low-mass protostars, tend be underpredicted by astrochemical models. This discrepancy might come from large beam single-dish telescopes, encompassing several components studied protostar, commonly used detect COMs. To address this issue, we have carried out multi-line observations methanol and COMs two protostars NGC1333-IRAS2A -IRAS4A Plateau de Bure interferometer at an...
Context. Modern versions of the Miller-Urey experiment claim that formamide (NH2CHO) could be starting point for formation metabolic and genetic macromolecules. Intriguingly, is indeed observed in regions forming solar-type stars external galaxies.
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 IRAM Large Program "Astrochemical Surveys At IRAM" (ASAI). Several COMs are unambiguously detected, some first time, such ketene H$_2$CCO, dimethyl ether (CH$_3$OCH$_3$) and glycolaldehyde (HCOCH$_2$OH), others firmly confirmed, formic acid (HCOOH) ethanol (C$_2$H$_5$OH). Thanks to high sensitivity observations full coverage 1, 2 3mm wavelength...
Evidence is mounting that the small bodies of our Solar System, such as comets and asteroids, have at least partially inherited their chemical composition from first phases System formation. It then appears molecular complexity these most likely related to earliest stages star therefore important characterize understand how evolution changes with solar-type protostellar evolution. We present here Large Program "Astrochemical Surveys At IRAM" (ASAI). Its goal carry out unbiased millimeter...
The L1544 pre-stellar core has been observed as part of the ASAI IRAM 30 m Large Program well follow-up programs. These observations have revealed chemical richness earliest phases low-mass star-forming regions. In this paper, we focus on 21 sulphur bearing species (ions, isotopomers, and deuteration) that detected in spectral-survey through 51 transitions: CS, CCS, C3S, SO, SO2, H2CS, OCS, HSCN, NS, HCS+, NS+, H2S. We also report tentative detection (4σ level) for methyl mercaptan (CH3SH)....