The two hot corinos of the SVS13-A protostellar binary system: counterposed siblings

We present ALMA high-angular resolution ($\sim$ 50 au) observations of the Class I binary system SVS13-A. We report images of SVS13-A in numerous interstellar complex organic molecules: CH$_{\rm 3}$OH, $^{13}$CH$_{\rm 3}$OH, CH$_{\rm 3}$CHO, CH$_{\rm 3}$OCH$_{\rm 3}$, and NH$_{\rm 2}$CHO. Two hot corinos at different velocities are imaged in VLA4A (V$_{sys}$= +7.7 km s$^{-1}$) and VLA4B (V$_{sys}$= +8.5 km s$^{-1}$). From a non-LTE analysis of methanol lines we derive a gas density of 3 $\times$ 10$^8$ cm$^{-3}$, and gas temperatures of 140 K and 170 K for VLA4A and VLA4B, respectively. For the other species the column densities are derived from a LTE analysis. Formamide, which is the only N-bearing species detected in our observations, is more prominent around VLA4A, while dimethyl ether, methanol and acetaldehyde are associated with both VLA4A and VLA4B. We derive in the two hot corinos abundance ratios of $\sim$ 1 for CH$_{\rm 3}$OH, $^{13}$CH$_{\rm 3}$OH, and CH$_{\rm 3}$OCH$_{\rm 3}$, $\sim$ 2 for CH$_{\rm 3}$CHO, and $\sim$ 4 for NH$_{\rm 2}$CHO. The present dataset supports a chemical segregation between the different species inside the binary system. The emerging picture is that of an onion-like structure of the two SVS13-A hot corinos, caused by the different binding energies of the species, also supported by ad hoc quantum chemistry calculations. In addition, the comparison between molecular and dust maps suggests that the interstellar complex organic molecules emission originates from slow shocks produced by accretion streamers impacting the VLA4A and VLA4B disks and enriching the gas-phase component.Comment: 20 pages, 14 figure

Streamers feeding the SVS13-A protobinary system: astrochemistry reveals accretion shocks?

We report ALMA high-angular resolution (~ 50 au) observations of the binary system SVS13-A. More specifically, we analyse deuterated water (HDO) and sulfur dioxide (SO2) emission. The molecular emission is associated with both the components of the binary system, VLA4A and VLA4B. The spatial distribution is compared to that of formamide (NH2CHO), previously analysed in the system. Deuterated water reveals an additional emitting component spatially coincident with the dust accretion streamer, at a distance larger than 120 au from the protostars, and at blue-shifted velocities (> 3 km/s from the systemic velocities). We investigate the origin of the molecular emission in the streamer, in light of thermal sublimation temperatures calculated using updated binding energies (BE) distributions. We propose that the observed emission is produced by an accretion shock at the interface between the accretion streamer and the disk of VLA4A. Thermal desorption is not completely excluded in case the source is actively experiencing an accretion burst.Comment: Accepted for publication in Faraday Discussions 202

Matrix Isolation Infrared Spectroscopic and Theoretical Study of the Interaction of Water with Dimethyl Methylphosphonate

Matrix isolation infrared spectroscopy has been combined with theoretical calculations for the characterization of the 1:1 hydrogen-bonded complex between H2O and dimethyl methylphosphonate (DMMP). The symmetric O-H stretching mode was observed to shift 203 cm-1 to lower energy upon hydrogen bond formation, while a 32 cm-1 blue shift was noted for the H-O-H bending mode of the H2O subunit in the complex. These values compare extremely well with the (unscaled) shifts of -203 and +32 cm-1, respectively, that were calculated theoretically at the MP2/6-31+G** level. Additional perturbed modes of the DMMP subunit were observed, shifted relative to the parent band position. The greatest perturbation was to the P=O stretching mode near 1270 cm-1, where a shift of -17 cm-1 was observed (-21 cm-1 calculated theoretically). This suggests that the site of hydrogen bonding in the complex is at the P=O group, in agreement with theoretical calculations. The binding energy ΔE° for the 1:1 complex was calculated to be -7.7 kcal/mol

Hot Corinos Chemical Diversity: Myth or Reality?

After almost 20 years of hunting, only about a dozen hot corinos, hot regions enriched in interstellar complex organic molecules (iCOMs), are known. Of them, many are binary systems with the two components showing drastically different molecular spectra. Two obvious questions arise. Why are hot corinos so difficult to find and why do their binary components seem chemically different? The answer to both questions could be a high dust opacity that would hide the molecular lines. To test this hypothesis, we observed methanol lines at centimeter wavelengths, where dust opacity is negligible, using the Very Large Array interferometer. We targeted the NGC 1333 IRAS 4A binary system, for which one of the two components, 4A1, has a spectrum deprived of iCOMs lines when observed at millimeter wavelengths, while the other component, 4A2, is very rich in iCOMs. We found that centimeter methanol lines are similarly bright toward 4A1 and 4A2. Their non-LTE analysis indicates gas density and temperature ($\geq2\times10^6$ cm$^{-3}$ and 100--190 K), methanol column density ($\sim10^{19}$ cm$^{-2}$) and extent ($\sim$35 au in radius) similar in 4A1 and 4A2, proving that both are hot corinos. Furthermore, the comparison with previous methanol line millimeter observations allows us to estimate the optical depth of the dust in front of 4A1 and 4A2, respectively. The obtained values explain the absence of iCOMs line emission toward 4A1 at millimeter wavelengths and indicate that the abundances toward 4A2 are underestimated by $\sim$30\%. Therefore, centimeter observations are crucial for the correct study of hot corinos, their census, and their molecular abundances.Comment: 9 pages, 3 figures, 2 Tables - Published in ApJ Letter

FAUST X: Formaldehyde in the Protobinary System [BHB2007] 11: Small Scale Deuteration

Context. Deuterium in H-bearing species is enhanced during the early stages of star formation, however, only a small number of high spatial resolution deuteration studies exist towards protostellar objects, leaving the small-scale structures unrevealed and understudied. Aims. We aim to constrain the deuterium fractionation ratios in a Class 0/I protostellar object in formaldehyde (H2CO), which has abundant deuterated isotopologues in this environment. Methods. We observed the Class 0/I protobinary system [BHB2007] 11, whose emission components are embedded in circumstellar disks that have radii of 2-3 au, using ALMA within the context of the Large Program FAUST. The system is surrounded by a complex filamentary structure connecting to the larger circumbinary disk. In this work we present the first study of formaldehyde D-fractionation towards this source with detections of H2CO 3(0,3)-2(0,2), combined with HDCO 4(2,2)-3(2,1), HDCO 4(1,4)-3(1,3) and D2CO 4(0,4)-3(0,3). These observations enable multiple velocity components associated with the methanol hotspots also uncovered by FAUST data, as well as the external envelope, to be resolved. In addition, based on the kinematics seen in the observations of the H2CO emission, we propose the presence of a second large scale outflow. Results. HDCO and D2CO are only found in the central regions of the core while H2CO is found more ubiquitously. From radiative transfer modelling, the column densities ranges found for H2CO, HDCO and D2CO are (3-8)x10$^{14}$ cm$^{-2}$, (0.8-2.9)x10$^{13}$ cm$^{-2}$ and (2.6-4.3)x10$^{12}$ cm$^{-2}$, respectively, yielding an average D/H ratio of 0.01-0.04. Following the results of kinematic modelling, the second large scale feature is inconsistent with a streamer-like nature and we thus tentatively conclude that the feature is an asymmetric molecular outflow launched by a wide-angle disk wind.Comment: 17 pages, 15 figure

Covid-19 as a breakdown in the texture of social practices

A lot of things need to be repaired and a lot of relationships are in need of a knowledgeable mending. Can we start to talk/write about them? This invitation - sent by one of the authors to the others - led us, as feminist women in academia, to join together in an experimental writing about the effects of COVID-19 on daily social practices and on potential (and innovative) ways for repairing work in different fields of social organization. By diffractively intertwining our embodied experiences of becoming together-with Others, we foreground a multiplicity of repair (care) practices COVID-19 is making visible. Echoing one another, we take a stand and say that we need to prevent the future from becoming the past. We are not going back to the past; our society has already changed and there is a need to cope with innovation and repairing practices that do not reproduce the past.Funding Agencies|European Research Council (ERC) under the European Unions Horizon 2020 research and innovation programmeEuropean Research Council (ERC) [715950]</p

Differential Selection on Carotenoid Biosynthesis Genes as a Function of Gene Position in the Metabolic Pathway: A Study on the Carrot and Dicots

Background: Selection of genes involved in metabolic pathways could target them differently depending on the position of genes in the pathway and on their role in controlling metabolic fluxes. This hypothesis was tested in the carotenoid biosynthesis pathway using population genetics and phylogenetics. Methodology/Principal Findings: Evolutionary rates of seven genes distributed along the carotenoid biosynthesis pathway

Effect of angiotensin-converting enzyme inhibitor and angiotensin receptor blocker initiation on organ support-free days in patients hospitalized with COVID-19

IMPORTANCE Overactivation of the renin-angiotensin system (RAS) may contribute to poor clinical outcomes in patients with COVID-19. Objective To determine whether angiotensin-converting enzyme (ACE) inhibitor or angiotensin receptor blocker (ARB) initiation improves outcomes in patients hospitalized for COVID-19. DESIGN, SETTING, AND PARTICIPANTS In an ongoing, adaptive platform randomized clinical trial, 721 critically ill and 58 non–critically ill hospitalized adults were randomized to receive an RAS inhibitor or control between March 16, 2021, and February 25, 2022, at 69 sites in 7 countries (final follow-up on June 1, 2022). INTERVENTIONS Patients were randomized to receive open-label initiation of an ACE inhibitor (n = 257), ARB (n = 248), ARB in combination with DMX-200 (a chemokine receptor-2 inhibitor; n = 10), or no RAS inhibitor (control; n = 264) for up to 10 days. MAIN OUTCOMES AND MEASURES The primary outcome was organ support–free days, a composite of hospital survival and days alive without cardiovascular or respiratory organ support through 21 days. The primary analysis was a bayesian cumulative logistic model. Odds ratios (ORs) greater than 1 represent improved outcomes. RESULTS On February 25, 2022, enrollment was discontinued due to safety concerns. Among 679 critically ill patients with available primary outcome data, the median age was 56 years and 239 participants (35.2%) were women. Median (IQR) organ support–free days among critically ill patients was 10 (–1 to 16) in the ACE inhibitor group (n = 231), 8 (–1 to 17) in the ARB group (n = 217), and 12 (0 to 17) in the control group (n = 231) (median adjusted odds ratios of 0.77 [95% bayesian credible interval, 0.58-1.06] for improvement for ACE inhibitor and 0.76 [95% credible interval, 0.56-1.05] for ARB compared with control). The posterior probabilities that ACE inhibitors and ARBs worsened organ support–free days compared with control were 94.9% and 95.4%, respectively. Hospital survival occurred in 166 of 231 critically ill participants (71.9%) in the ACE inhibitor group, 152 of 217 (70.0%) in the ARB group, and 182 of 231 (78.8%) in the control group (posterior probabilities that ACE inhibitor and ARB worsened hospital survival compared with control were 95.3% and 98.1%, respectively). CONCLUSIONS AND RELEVANCE In this trial, among critically ill adults with COVID-19, initiation of an ACE inhibitor or ARB did not improve, and likely worsened, clinical outcomes. TRIAL REGISTRATION ClinicalTrials.gov Identifier: NCT0273570

Diversité chimique organique dans les proto-étoiles de type solaire : le proto-système solaire a-t-il connu une phase 'hot corino' ?

The Solar System was born 4.5 billion years ago from a cold clump of a molecular cloud of the Milky Way. Astrochemistry is a powerful tool to elucidate (1) what happened to the first phases of the Solar System formation and (2) how they might have influenced the early development of organicchemistry and perhaps the appearance of life on Earth. The observations so far show a large diversity in the chemical composition of solar-mass protostars. In particular, hot corinos and WCCC (Warm Carbon-Chain Chemistry) objects are chemically distinct: while hot corinos are rich in interstellar complex organic molecules, or iCOMs (which might be bricks of large terrestrial biomolecules), WCCC objects are rich in hydrocarbons. This protostellar chemical diversity could reflect a difference in the chemical composition of the grains ice mantle set during the pre-stellar core phase. Whether the environment affects this diversity and how is still an open question.Only a few solar-mass hot corinos and WCCC objects have been identified to date, thus making it difficult to assess which one of these is dominant in our Galaxy, if any. Most studies targeting hot corinos are performed towards low-mass star-forming regions whereas our Sun is believed to be born in a large cluster with high-mass (>8 M o) stars. Studies of solar-mass protostars in low- to high- mass star-forming regions are mandatory to shed light on the Sun's chemical past. The first objective of the thesis is to investigate the chemical nature of solar-mass protostars located in a region similar to the one where our Sun was born, and to address the question of whether or not the Sun underwent a hot corino phase during its formation. The second objective is to understand whether the environment plays a role in the chemical diversity of solar-mass protostars. To do so, I explored the chemical contents of nine bona fide solar-mass protostars located in the OMC-2/3 filament, the best and closest analogue to our Sun's birth environment. I exploited single-dish and interferometric datasets and targeted exclusively the molecular tracers of hot corinos and WCCC objects.Unexpectedly, single-dish observations proved to be ineffective in searching for hot corinos and WCCC objects in OMC-2/3. The molecular tracers used are very likely contaminated by the photodissociation region surrounding the filament. Then, I performed both a dust continuum and a molecular line analysis with the ALMA observations. The dust continuum study shows that the dust properties of the OMC-2/3 protostars are not affected by the high-UV illumination, and that star formation is simultaneous throughout the filament. Finally, from the molecular line analysis, I detected five new bona fide hot corinos in OMC-2/3. This result is different from what was found in low-mass star-forming regions where hot corinos are abundant. Hot corinos seem therefore to be scarcer in a high UV-illuminated environment, which suggests that the latter is very likely playing a role in the chemical content of solar-mass protostars. Finally, hot corinos do not seem to prevail in a region similar to the Sun's birth environment. The question of whether our Sun experienced a hot corino phase needs further research to be answered.Le système solaire est né il y a 4,5 milliards d'années dans un nuage moléculaire de la Voie lactée. L'astrochimie est un outil puissant pour élucider (1) ce qui est arrivé aux premières phases de la formation du système solaire et (2) comment elles ont pu influencer le début du développement de la chimie organique et peut-être de l'apparition de la vie sur Terre. Les observations effectuées jusqu'à présent montrent une grande diversité dans la composition chimique des proto-étoiles de masse solaire. En particulier, les "hot corinos" et les objets WCCC ("Warm Carbon-Chain Chemistry", soit la chimie chaude des chaines carbonées) sont chimiquement distincts : les "hot corinos" sont riches en molécules organiques complexes interstellaires, ou iCOMs (qui pourraient être des briques de grandes biomolécules terrestres), tandis que les objets WCCC sont riches en hydrocarbures. Cette diversité chimique protostellaire pourrait refléter une différence dans la composition chimique du manteau de glace des grains mis en place pendant la phase pré-stellaire. La question de savoir si l'environnement affecte cette diversité et comment, reste ouverte.Peu de "hot corinos" et objets WCCC ont été identifiés à ce jour. La plupart des études ciblant les "hot corinos" vise des régions de formation d'étoiles de faible masse, alors que notre Soleil est censé être né près d'étoiles massives (>8 M o). Les études de proto-étoiles dans ces régions sont essentielles pour comprendre le passé chimique du Soleil. Le premier but de la thèse est d'étudier la nature chimique des proto-étoiles situées dans une région similaire à celle où notre Soleil est né, et de déterminer si le Soleil a subi une phase "hot corino" pendant sa formation. Le second but est de comprendre si l'environnement joue un rôle dans la diversité chimique des proto-étoiles. Pour cela, j'ai étudié neuf proto-étoiles du filament OMC-2/3, la plus proche région similaire à l'environement de naissance du Soleil. J'ai exploité des sets de données "single-dish" et interférométriques et ciblé seulement les traceurs moléculaires des "hot corinos" et des objets WCCC.Les observations "single-dish" se sont révélées inefficaces dans la recherche de "hot corinos" et d'objets WCCC dans OMC-2/3, à cause de la contamination des traceurs moléculaires utilisés par la région de photodissociation entourant le filament. Ensuite, j'ai réalisé une analyse de la poussière et des raies moléculaires avec les observations ALMA. L'étude de la poussière montre que ses propriétés ne sont pas affectées par l'illumination UV, et que la formation d'étoiles est simultanée dans tout le filament. Enfin, à partir de l'analyse des raies moléculaires, j'ai détecté cinq nouveaux "hot corino" dans OMC-2/3. Ce résultat diffère de ce qui a été trouvé dans les autres régions de formation d'étoiles, où les "hot corinos" sont abondants. Ceux-ci semblent donc être rares dans un environnement fortement illuminé, ce qui suggère que l'environement affecte probablement la diversité chimique des proto-étoiles. Enfin, l'ancienne nature "hot corino" du Soleil doit faire l'objet d'une étude plus approfondie

Diversity of organic richness in solar-type protostars : did the proto-solar-system experience a hot corino phase ?

Le système solaire est né il y a 4,5 milliards d'années dans un nuage moléculaire de la Voie lactée. L'astrochimie est un outil puissant pour élucider (1) ce qui est arrivé aux premières phases de la formation du système solaire et (2) comment elles ont pu influencer le début du développement de la chimie organique et peut-être de l'apparition de la vie sur Terre. Les observations effectuées jusqu'à présent montrent une grande diversité dans la composition chimique des proto-étoiles de masse solaire. En particulier, les "hot corinos" et les objets WCCC ("Warm Carbon-Chain Chemistry", soit la chimie chaude des chaines carbonées) sont chimiquement distincts : les "hot corinos" sont riches en molécules organiques complexes interstellaires, ou iCOMs (qui pourraient être des briques de grandes biomolécules terrestres), tandis que les objets WCCC sont riches en hydrocarbures. Cette diversité chimique protostellaire pourrait refléter une différence dans la composition chimique du manteau de glace des grains mis en place pendant la phase pré-stellaire. La question de savoir si l'environnement affecte cette diversité et comment, reste ouverte.Peu de "hot corinos" et objets WCCC ont été identifiés à ce jour. La plupart des études ciblant les "hot corinos" vise des régions de formation d'étoiles de faible masse, alors que notre Soleil est censé être né près d'étoiles massives (>8 M o). Les études de proto-étoiles dans ces régions sont essentielles pour comprendre le passé chimique du Soleil. Le premier but de la thèse est d'étudier la nature chimique des proto-étoiles situées dans une région similaire à celle où notre Soleil est né, et de déterminer si le Soleil a subi une phase "hot corino" pendant sa formation. Le second but est de comprendre si l'environnement joue un rôle dans la diversité chimique des proto-étoiles. Pour cela, j'ai étudié neuf proto-étoiles du filament OMC-2/3, la plus proche région similaire à l'environement de naissance du Soleil. J'ai exploité des sets de données "single-dish" et interférométriques et ciblé seulement les traceurs moléculaires des "hot corinos" et des objets WCCC.Les observations "single-dish" se sont révélées inefficaces dans la recherche de "hot corinos" et d'objets WCCC dans OMC-2/3, à cause de la contamination des traceurs moléculaires utilisés par la région de photodissociation entourant le filament. Ensuite, j'ai réalisé une analyse de la poussière et des raies moléculaires avec les observations ALMA. L'étude de la poussière montre que ses propriétés ne sont pas affectées par l'illumination UV, et que la formation d'étoiles est simultanée dans tout le filament. Enfin, à partir de l'analyse des raies moléculaires, j'ai détecté cinq nouveaux "hot corino" dans OMC-2/3. Ce résultat diffère de ce qui a été trouvé dans les autres régions de formation d'étoiles, où les "hot corinos" sont abondants. Ceux-ci semblent donc être rares dans un environnement fortement illuminé, ce qui suggère que l'environement affecte probablement la diversité chimique des proto-étoiles. Enfin, l'ancienne nature "hot corino" du Soleil doit faire l'objet d'une étude plus approfondie.The Solar System was born 4.5 billion years ago from a cold clump of a molecular cloud of the Milky Way. Astrochemistry is a powerful tool to elucidate (1) what happened to the first phases of the Solar System formation and (2) how they might have influenced the early development of organicchemistry and perhaps the appearance of life on Earth. The observations so far show a large diversity in the chemical composition of solar-mass protostars. In particular, hot corinos and WCCC (Warm Carbon-Chain Chemistry) objects are chemically distinct: while hot corinos are rich in interstellar complex organic molecules, or iCOMs (which might be bricks of large terrestrial biomolecules), WCCC objects are rich in hydrocarbons. This protostellar chemical diversity could reflect a difference in the chemical composition of the grains ice mantle set during the pre-stellar core phase. Whether the environment affects this diversity and how is still an open question.Only a few solar-mass hot corinos and WCCC objects have been identified to date, thus making it difficult to assess which one of these is dominant in our Galaxy, if any. Most studies targeting hot corinos are performed towards low-mass star-forming regions whereas our Sun is believed to be born in a large cluster with high-mass (>8 M o) stars. Studies of solar-mass protostars in low- to high- mass star-forming regions are mandatory to shed light on the Sun's chemical past. The first objective of the thesis is to investigate the chemical nature of solar-mass protostars located in a region similar to the one where our Sun was born, and to address the question of whether or not the Sun underwent a hot corino phase during its formation. The second objective is to understand whether the environment plays a role in the chemical diversity of solar-mass protostars. To do so, I explored the chemical contents of nine bona fide solar-mass protostars located in the OMC-2/3 filament, the best and closest analogue to our Sun's birth environment. I exploited single-dish and interferometric datasets and targeted exclusively the molecular tracers of hot corinos and WCCC objects.Unexpectedly, single-dish observations proved to be ineffective in searching for hot corinos and WCCC objects in OMC-2/3. The molecular tracers used are very likely contaminated by the photodissociation region surrounding the filament. Then, I performed both a dust continuum and a molecular line analysis with the ALMA observations. The dust continuum study shows that the dust properties of the OMC-2/3 protostars are not affected by the high-UV illumination, and that star formation is simultaneous throughout the filament. Finally, from the molecular line analysis, I detected five new bona fide hot corinos in OMC-2/3. This result is different from what was found in low-mass star-forming regions where hot corinos are abundant. Hot corinos seem therefore to be scarcer in a high UV-illuminated environment, which suggests that the latter is very likely playing a role in the chemical content of solar-mass protostars. Finally, hot corinos do not seem to prevail in a region similar to the Sun's birth environment. The question of whether our Sun experienced a hot corino phase needs further research to be answered