Publications (27)15.7 Total impact
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Article: From Prestellar to Protostellar Cores II. Time Dependence and Deuterium Fractionation
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ABSTRACT: We investigate the molecular evolution and D/H abundance ratios that develop as star formation proceeds from a dense-cloud core to a protostellar core, by solving a gas-grain reaction network applied to a 1-D radiative hydrodynamic model with infalling fluid parcels. Spatial distributions of gas and ice-mantle species are calculated at the first-core stage, and at times after the birth of a protostar. Gas-phase methanol and methane are more abundant than CO at radii $r\lesssim 100$ AU in the first-core stage, but gradually decrease with time, while abundances of larger organic species increase. The warm-up phase, when complex organic molecules are efficiently formed, is longer-lived for those fluid parcels in-falling at later stages. The formation of unsaturated carbon chains (warm carbon-chain chemistry) is also more effective in later stages; C$^+$, which reacts with CH$_4$ to form carbon chains, increases in abundance as the envelope density decreases. The large organic molecules and carbon chains are strongly deuterated, mainly due to high D/H ratios in the parent molecules, determined in the cold phase. We also extend our model to simulate simply the chemistry in circumstellar disks, by suspending the 1-D infall of a fluid parcel at constant disk radii. The species CH$_3$OCH$_3$ and HCOOCH$_3$ increase in abundance in $10^4-10^5$ yr at the fixed warm temperature; both also have high D/H ratios.10/2012; -
Article: Chemistry in the First Hydrostatic Core Stage By Adopting Three-Dimensional Radiation Hydrodynamic Simulations
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ABSTRACT: We investigate molecular evolution from a molecular cloud core to a first hydrostatic core in three spatial dimensions. We perform a radiation hydrodynamic simulation in order to trace fluid parcels, in which molecular evolution is investigated, using a gas-phase and grain-surface chemical reaction network. We derive spatial distributions of molecular abundances and column densities in the core harboring the first core. We find that the total of gas and ice abundances of many species in a cold era (10 K) remain unaltered until the temperature reaches ~500 K. The gas abundances in the warm envelope and the outer layer of the first core (T < 500 K) are mainly determined via the sublimation of ice-mantle species. Above 500 K, the abundant molecules, such as H2CO, start to be destroyed, and simple molecules, such as CO, H2O and N2 are reformed. On the other hand, some molecules are effectively formed at high temperature; carbon-chains, such as C2H2 and cyanopolyynes, are formed at the temperature of >700 K. We also find that large organic molecules, such as CH3OH and HCOOCH3, are associated with the first core (r < 10 AU). Although the abundances of these molecules in the first core stage are comparable or less than in the protostellar stage (hot corino), reflecting the lower luminosity of the central object, their column densities in our model are comparable to the observed values toward the prototypical hot corino, IRAS 16293-2422. We propose that these large organic molecules can be good tracers of the first cores.07/2012; -
Article: Elemental nitrogen partitioning in dense interstellar clouds.
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ABSTRACT: Many chemical models of dense interstellar clouds predict that the majority of gas-phase elemental nitrogen should be present as N(2), with an abundance approximately five orders of magnitude less than that of hydrogen. As a homonuclear diatomic molecule, N(2) is difficult to detect spectroscopically through infrared or millimeter-wavelength transitions. Therefore, its abundance is often inferred indirectly through its reaction product N(2)H(+). Two main formation mechanisms, each involving two radical-radical reactions, are the source of N(2) in such environments. Here we report measurements of the low temperature rate constants for one of these processes, the N + CN reaction, down to 56 K. The measured rate constants for this reaction, and those recently determined for two other reactions implicated in N(2) formation, are tested using a gas-grain model employing a critically evaluated chemical network. We show that the amount of interstellar nitrogen present as N(2) depends on the competition between its gas-phase formation and the depletion of atomic nitrogen onto grains. As the reactions controlling N(2) formation are inefficient, we argue that N(2) does not represent the main reservoir species for interstellar nitrogen. Instead, elevated abundances of more labile forms of nitrogen such as NH(3) should be present on interstellar ices, promoting the eventual formation of nitrogen-bearing organic molecules.Proceedings of the National Academy of Sciences 06/2012; 109(26):10233-8. · 9.68 Impact Factor -
Article: Review of OCS gas-phase reactions in dark cloud chemical models
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ABSTRACT: The association reaction S + CO {\to} OCS + hnu has been identified as being particularly important for the prediction of gas-phase OCS abundances by chemical models of dark clouds. We performed detailed ab-initio calculations for this process in addition to undertaking an extensive review of the neutral-neutral reactions involving this species which might be important in such environments. The rate constant for this association reaction was estimated to be several orders of magnitude smaller than the one present in current astrochemical databases. The new rate for this reaction and the introduction of other processes, notably OH + CS {\to} OCS + H and C + OCS {\to} CO + CS, dramatically changes the OCS gas-phase abundance predicted by chemical models for dark clouds. The disagreement with observations in TMC-1 (CP) and L134N (N), suggests that OCS may be formed on grain surfaces as is the case for methanol. The observation of solid OCS on interstellar ices supports this hypothesis.01/2012; -
Article: CID: Chemistry in disks VI.sulfur-bearing molecules in the protoplanetary disks surrounding LkCa15, MWC480, DM Tau, and GO Tau
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ABSTRACT: We study the content in S-bearing molecules of protoplanetary disks around low-mass stars. We used the new IRAM 30-m receiver EMIR to perform simultaneous observations of the $1_{10}-1_{01}$ line of H$_2$S at 168.8 GHz and $2_{23}-1_{12}$ line of SO at 99.3 GHz. We compared the observational results with predictions coming from the astrochemical code NAUTILUS, which has been adapted to protoplanetary disks. The data were analyzed together with existing CS J=3-2 observations. We fail to detect the SO and H$_2$S lines, although CS is detected in LkCa15, DM\,Tau, and GO\,Tau but not in MWC\,480. However, our new upper limits are significantly better than previous ones and allow us to put some interesting constraints on the sulfur chemistry. Our best modeling of disks is obtained for a C/O ratio of 1.2, starting from initial cloud conditions of H density of $2\times 10^5$ cm$^{-3}$ and age of $10^6$ yr. The results agree with the CS data and are compatible with the SO upper limits, but fail to reproduce the H$_2$S upper limits. The predicted H$_2$S column densities are too high by at least one order of magnitude. H$_2$S may remain locked onto grain surfaces and react with other species, thereby preventing the desorption of H$_2$S.09/2011; -
Article: Hydrodynamical-Chemical Models from Prestellar Cores to Protostellar Cores
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ABSTRACT: We investigate the molecular evolution in star forming cores from dense cloud cores (nH ~ 104 cm−3, T ~ 10 K) to protostellar cores. A detailed gas-grain reaction network is solved in infalling fluid parcels in 1-D radiation hydrodynamic model. Large organic molecules are mainly formed via grain-surface reaction at T ~ several 10 K and sublimated to the gas-phase at ~ 100 K, while carbon-chain species are formed at a few 10 K after the sublimation of CH4 ice. The former accounts for the high abundance of large organic molecules in hot corinos such as IRAS16293, and the latter accounts for the carbon chain species observed toward L1527. The relative abundance of carbon chain species and large organic species would depend on the collapse time scale and/or temperature in the dense core stage. The large organic molecules and carbon chains in the protostellar cores are heavily deuterated; although they are formed in the warm temperatures, their ingredients have high D/H ratios, which are set in the cold core phase and isothermal collapse phase. HCOOH is formed by the gas-phase reaction of OH with the sublimated H2CO, and is further enriched in Deuterium due to the exothermic exchange reaction of OH + D → OD + H.In the fluid parcels of the 1-D collapse model, warm temperature T. ~ several 10 K lasts for only ~ 104 yr, and the fluid parcels fall to the central star in ~ 100 yr after the temperature of the parcel rises to T ≥ 100 K. These timescales are determined by the size of the warm region and infall (~ free-fall) velocity: rwarm/tff. In reality, circum stellar disk is formed, in which fluid parcels stay for a longer timescale than the infall timescale. We investigate the molecular evolution in the disk by simply assuming that a fluid parcel stays at a constant temperature and density (i.e. a fixed disk radius) for 104 − 105 yrs. We found that some organic species which are underestimated in our 1-D collapse model, such as CH3OCH3 and HCOOCH3, become abundant in the disk. We also found that these disk species have very high D/H ratio as well, since their ingredients are highly deuterated.Finally we investigate molecular evolution in a 3D hydrodynamic simulation of star forming core. We found CH3OH are abundant in the vicinity of the first core. The abundances of large organic species are determined mainly by the local temperature (sublimation), because of the short lifetime of the first core and the efficient mass accretion via angular momentum transfer.Proceedings of the International Astronomical Union 05/2011; 7:33 - 42. -
Article: Sensitivity analysis list of chemical reactions (Wakelam+, 2010)
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ABSTRACT: The osu032008 network is the list of chemical reactions used sensitivity analysis. This file contains reactants and products of each reaction, three parameters (alpha, beta and gamma) to compute the rate coefficients and the type of reaction. This network lists 4479 reactions for 455 species with 13 atoms. More details on the types of reactions and formula to compute the rate coefficients can be found at http://www.physics.ohio-state.edu/~eric/research.html (1 data file).03/2010; -
Article: A sensitivity study of the neutral-neutral reactions C + C3 and C + C5 in cold dense interstellar clouds
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ABSTRACT: Chemical networks used for models of interstellar clouds contain many reactions, some of them with poorly determined rate coefficients and/or products. In this work, we report a method for improving the predictions of molecular abundances using sensitivity methods and ab initio calculations. Based on the chemical network osu.2003, we used two different sensitivity methods to determine the most important reactions as a function of time for models of dense cold clouds. Of these reactions, we concentrated on those between C and C3 and between C and C5, both for their effect on specific important species such as CO and for their general effect on large numbers of species. We then used ab initio and kinetic methods to determine an improved rate coefficient for the former reaction and a new set of products, plus a slightly changed rate coefficient for the latter. Putting our new results in a pseudo-time-dependent model of cold dense clouds, we found that the abundances of many species are altered at early times, based on large changes in the abundances of CO and atomic C. We compared the effect of these new rate coefficients/products on the comparison with observed abundances and found that they shift the best agreement from 3e4 yr to (1-3)e5 yr.01/2009; -
Article: Polycyclic Aromatic Hydrocarbons in Dense Cloud Chemistry
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ABSTRACT: Virtually all detailed gas-phase models of the chemistry of dense interstellar clouds exclude polycyclic aromatic hydrocarbons (PAHs). This omission is unfortunate because from the few studies that have been done on the subject, it is known that the inclusion of PAHs can affect the gas-phase chemistry strongly. We have added PAHs to our network to determine the role they play in the chemistry of cold dense cores. Initially, only the chemistry of neutral and negatively charged PAH species was considered, since it was assumed that positively charged PAHs are of little importance. Subsequently, this assumption was checked and confirmed. In the models presented here, we include radiative attachment to form PAH−, mutual neutralization between PAH anions and small positively charged ions, and photodetachment. We also test the sensitivity of our results to changes in the size and abundance of the PAHs. Our results confirm that the inclusion of PAHs changes many of the calculated abundances of smaller species considerably. In TMC-1, the general agreement with observations is significantly improved, unlike in L134N. This may indicate a difference in PAH properties between the two regions. With the inclusion of PAHs in dense cloud chemistry, high-metal elemental abundances give a satisfactory agreement with observations. As a result, we do not need to decrease the observed elemental abundances of all metals, and we do not need to vary the elemental C/O ratio in order to produce large abundances of carbon species in TMC-1 (CP).The Astrophysical Journal 12/2008; 680(1):371. · 6.02 Impact Factor -
Article: Polycylcic Aromatic Hydrocarbons (PAH's) in dense cloud chemistry
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ABSTRACT: Virtually all detailed gas-phase models of the chemistry of dense interstellar clouds exclude polycyclic aromatic hydrocarbons (PAH's). This omission is unfortunate because from the few studies that have been done on the subject, it is known that the inclusion of PAH's can affect the gas-phase chemistry strongly. We have added PAH's to our network to determine the role they play in the chemistry of cold dense cores. In the models presented here, we include radiative attachment to form PAH-, mutual neutralization between PAH anions and small positively-charged ions, and photodetachment. We also test the sensitivity of our results to changes in the size and abundance of the PAH's. Our results confirm that the inclusion of PAH's changes many of the calculated abundances of smaller species considerably. In TMC-1, the general agreement with observations is significantly improved contrary to L134N. This may indicate a difference in PAH properties between the two regions. With the inclusion of PAH's in dense cloud chemistry, high-metal elemental abundances give a satisfactory agreement with observations. As a result, we do not need to decrease the observed elemental abundances of all metals and we do not need to vary the elemental C/O ratio in order to produce large abundances of carbon species in TMC-1 (CP). Comment: Accepted to ApJ. Astrophysical Journal (2008) accepted02/2008; -
Article: Molecular evolution in star-forming cores: From prestellar cores to protostellar cores
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ABSTRACT: We investigate the molecular abundances in protostellar cores by solving the gas-grain chemical reaction network. As a physical model of the core, we adopt a result of one-dimensional radiation-hydrodynamics calculation, which follows the contraction of an initially hydrostatic prestellar core to form a protostellar core. Temporal variation of molecular abundances is solved in multiple infalling shells, which enable us to investigate the spatial distribution of molecules in the evolving core. The shells pass through the warm region of T ~ 20–100 K in several 104 yr and falls onto the central star in ~100 yr after they enter the region of T > 100 K. We found that the complex organic species such as HCOOCH3 are formed mainly via grain-surface reactions at T ~ 20–40 K, and then sublimated to the gas phase when the shell temperature reaches their sublimation temperatures (T ≥ 100 K). Carbon-chain species can be re-generated from sublimated CH4 via gas-phase and grain-surface reactions. HCO2+, which is recently detected towards L1527, are abundant at r = 100–2,000 AU, and its column density reaches ~1011 cm−2 in our model. If a core is isolated and irradiated directly by interstellar UV radiation, photo-dissociation of water ice produces OH, which reacts with CO to form CO2 efficiently. Complex species then become less abundant compared with the case of embedded core in ambient clouds. Although a circumstellar (protoplanetary) disk is not included in our core model, we can expect similar chemical reactions (i.e., production of large organic species, carbon-chains and HCO2+) to proceed in disk regions with T ~ 20–100 K.Proceedings of the International Astronomical Union 01/2008; 4:129 - 136. -
Article: Molecular Evolution and Star Formation: From Prestellar Cores to Protostellar Cores
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ABSTRACT: We investigate molecular evolution in a star-forming core that is initially a hydrostatic starless core and collapses to form a low-mass protostar. The results of a one-dimensional radiation-hydrodynamics calculation are adopted as a physical model of the core. We first derive radii at which CO and large organic species sublimate. CO sublimation in the central region starts shortly before the formation of the first hydrostatic core. When the protostar is born, the CO sublimation radius extends to 100 AU, and the region inside $\lesssim 10$ AU is hotter than 100 K, at which some large organic species evaporate. We calculate the temporal variation of physical parameters in infalling shells, in which the molecular evolution is solved using an updated gas-grain chemical model to derive the spatial distribution of molecules in a protostellar core. The shells pass through the warm region of $10 -100$ K in several $\times$ $10^4$ yr, and fall into the central star $\sim 100$ yr after they enter the region where $T \gtrsim 100$ K. We find that large organic species are formed mainly via grain-surface reactions at temperatures of $20 -40$ K and then desorbed into the gas-phase at their sublimation temperatures. Carbon-chain species can be formed by a combination of gas-phase reactions and grain-surface reactions following the sublimation of CH$_4$. Our model also predicts that CO$_2$ is more abundant in isolated cores, while gas-phase large organic species are more abundant in cores embedded in ambient clouds. Comment: 35 pages, 10 figures, accepted to ApJ10/2007; -
Article: Chemical sensitivity to the ratio of the cosmic-ray ionization rates of He and H2 in dense clouds
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ABSTRACT: Aim: To determine whether or not gas-phase chemical models with homogeneous and time-independent physical conditions explain the many observed molecular abundances in astrophysical sources, it is crucial to estimate the uncertainties in the calculated abundances and compare them with the observed abundances and their uncertainties. Non linear amplification of the error and bifurcation may limit the applicability of chemical models. Here we study such effects on dense cloud chemistry. Method: Using a previously studied approach to uncertainties based on the representation of rate coefficient errors as log normal distributions, we attempted to apply our approach using as input a variety of different elemental abundances from those studied previously. In this approach, all rate coefficients are varied randomly within their log normal (Gaussian) distribution, and the time-dependent chemistry calculated anew many times so as to obtain good statistics for the uncertainties in the calculated abundances. Results: Starting with so-called ``high-metal'' elemental abundances, we found bimodal rather than Gaussian like distributions for the abundances of many species and traced these strange distributions to an extreme sensitivity of the system to changes in the ratio of the cosmic ray ionization rate zeta\_He for He and that for molecular hydrogen zeta\_H2. The sensitivity can be so extreme as to cause a region of bistability, which was subsequently found to be more extensive for another choice of elemental abundances. To the best of our knowledge, the bistable solutions found in this way are the same as found previously by other authors, but it is best to think of the ratio zeta\_He/zeta\_H2 as a control parameter perpendicular to the ''standard'' control parameter zeta/n\_H. Comment: Accepted for publication08/2006; -
Article: The effect of uncertainties on chemical models of dark clouds
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ABSTRACT: The gas-phase chemistry of dark clouds has been studied with a treatment of uncertainties caused both by errors in individual rate coefficients and uncertainties in physical conditions. Moreover, a sensitivity analysis has been employed to attempt to determine which reactions are most important in the chemistry of individual species. The degree of overlap between calculated errors in abundances and estimated observational errors has been used as an initial criterion for the goodness of the model and the determination of a best 'chemical' age of the source. For the well-studied sources L134N and TMC-1CP, best agreement is achieved at so-called "early times" ~10$^{5}$ yr, in agreement with previous calculations but here put on a firmer statistical foundation. A more detailed criterion for agreement, which takes into account the degree of disagreement, is also proposed. Poorly understood but critical classes of reactions are delineated, especially reactions between ions and polar neutrals. Such reactions will have to be understood better before the chemistry can be made more secure. Nevertheless, the level of agreement is low enough to indicate that a static picture of physical conditions without consideration of interactions with grain surfaces is inappropriate for a complete understanding of the chemistry. Comment: Accepted for publication in A&A. Astronomy and Astrophysics in press (2006) in press01/2006; -
Article: Modeling the ortho-to-para abundance ratio of cyclic C3H2 in cold dense cores
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ABSTRACT: We report a detailed attempt to model the ortho-to-para abundance ratio of c-C3H2 so as to reproduce observed values in the cores of the well-known source TMC-1. According to observations, the ortho-to-para ratios vary, within large uncertainties, from a low of near unity to a high of approximately three depending on the core. We used the osu.2003 network of gas-phase chemical reactions augmented by reactions that specifically consider the formation, depletion, and interconversion of the ortho and para forms of the c-C3H2 and its precursor ion c-C3H3+. We investigated the sensitivity of the calculated ortho-to-para ratio for c-C3H2 to a large number of factors. For the less evolved cores C, CP, and D, we had no difficulty reproducing the observed ortho-to-para ratios of 1-2. Comment: Accepted for publication in A&A12/2005; -
Article: Estimation and reduction of the uncertainties in chemical models: Application to hot core chemistry
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ABSTRACT: It is not common to consider the role of uncertainties in the rate coefficients used in interstellar gas-phase chemical models. In this paper, we report a new method to determine both the uncertainties in calculated molecular abundances and their sensitivities to underlying uncertainties in the kinetic data utilized. The method is used in hot core models to determine if previous analyses of the age and the applicable cosmic-ray ionization rate are valid. We conclude that for young hot cores ($\le 10^4$ yr), the modeling uncertainties related to rate coefficients are reasonable so that comparisons with observations make sense. On the contrary, the modeling of older hot cores is characterized by strong uncertainties for some of the important species. In both cases, it is crucial to take into account these uncertainties to draw conclusions from the comparison of observations with chemical models. Comment: Accepted for publication in A&A09/2005; -
Article: Searching for sulphur polymers in young protostars with Herschel and ALMA
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ABSTRACT: Sulphur is a long-standing problem in the chemistry of the interstellar medium. This element is highly depleted on interstellar grains in dense sources but in an unobserved form. We have started to develop new clues regarding the form of the depleted sulphur using detailed modelling of the sulphur chemistry and comparisons with observations (Wakelam et al. 2004). This previous study underlined the possibility for sulphur to be depleted on grains in a polymeric form from S to S8 in complexity. Some of the lines of these species can be observed with ALMA and will require the high ALMA sensitivity and spatial resolution to be detected. In this contribution we discuss how possible ALMA observations could help to give constraints on the abundance of S-polymers. Finding these species would be an important step inthe understanding of the chemistry in both molecular clouds and protostars.12/2004; 577:435-436. -
Article: Far-infrared mineral spectra database for the analysis of future PACS/Herschel data
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ABSTRACT: The signature of carbonates has been found in both protoplanetary disks of evolved stars and environment of low mass protostars (Kemper et al. 2002, Ceccarelli et al. 2002). Both carbonates and sulphates are present in primitive carbonaceous chondrites. On Earth, the formation of carbonates (CO32-) is usually associated with sulphates (SO42-). Although the formation of such species is obviously different in the interstellar medium than on Earth (where it usually involve liquid water), we propose to search for the feature of sulphates in the environment of protostellar objects using PACS. For that we have started the construction of a far IR database of experimental spectra of minerals including sulphates. This database will be a useful tool to study the mineral composition of interstellar dust. In this contribution we will present the preliminary results of these studies.12/2004; 577:437-438. -
Article: First results of an unbiased millimeter spectral survey of the solar-type Protostar IRAS 16293-2422
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ABSTRACT: Unbiased line surveys are a unique way of determining the molecular content of astrophysical objects. They allow a complete study of the chemistry in and around molecular sources. Among all class 0 protostars observed to date, IRAS16293-2422 (IRAS16293) has the richest and brightest line spectrum. In particular this low mass protostar is the first one where several complex molecules have been observed (Cazaux et al. 2003) but also many deuterated molecules including D2CO (Ceccarelli et al. 1998) and doubly and triply deuterated methanol (Parise et al. 2002, Parise et al. 2004). It has been shown recently (Ceccarelli et al. 2000, Shoier et al. 2002) that the structure of the collapsing envelope around this low-mass protostar has a inner hot corino where the temperature exceeds 100 K, and a colder outer envelope. Due to its high temperature and density which excite many transitions not visible from cooler regions, this hot core is responsible for the richness of the IRAS16293 spectrum. Another reason for this richness comes from the molecular diversity of the source itself, due both to the release by the elevated temperature of molecules trapped in icy mantles, and to gas phase chemical reactions which can proceed faster at high density. Also the high temperatures open many chemical pathways which, because they are endothermic, are closed at lower temperatures. We present the first results of this millimetre unbiased spectral line survey performed with the IRAM-30m and JCMT radiotelescopes. When completed this survey will cover most of the frequency band attainable with the 30m (between 80 and 280 GHz) and with the JCMT in the 350 GHz band (328-366 GHz), i.e. about 205 GHz in total. A first very rough analysis shows the presence of many lines originating from various molecules including complex and deuterated molecules. The density of lines is about 20/GHz at 3σ, at any observed frequency. This survey will build a complete census of the molecular content of this object, and will allow a detailed modelling of the chemistry governing its hot core and envelope. The molecular composition ofIRAS16293 will be compared to what is already known for massive hot-core regions putting stringent constraints on chemical models.Proceedings of the International Astronomical Union 235:277P. -
Article: Sulphur-bearing species in the star forming region L1689N
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ABSTRACT: We report observations of the expected main S-bearingspecies (SO, SO2 and H2S) in the low-mass star forming regionL1689N. We obtained large scale (~300''x200'') maps ofseveral transitions from these molecules with the goal to study thesulphur chemistry, i.e. how the relative abundances change in thedifferent physical conditions found in L1689N. We identified eightinteresting regions, where we carried out a quantitative comparativestudy: the molecular cloud (as reference position), five shockedregions caused by the interaction of the molecular outflows with thecloud, and the two protostars IRAS16293-2422 and 16293E. In thecloud we carefully computed the gas temperature and density by meansof a non-LTE LVG code, while in other regions we used previousresults. We hence derived the column density of SO, SO2 andH2S, together with SiO and H2CO - which were observed previously- and their relevant abundance ratios. We find that SiO is themolecule that shows the largest abundance variations in the shockedregions, whereas S-bearing molecules show more moderate variations.Remarkably, the region of the brightest SiO emission in L1689Nis undetected in SO2, H2S andH2CO and only marginally detected in SO. In the other weaker SiOshocks, SO2 is enhanced with respect to SO. We propose a schema inwhich the different molecular ratios correspond to different ages ofthe shocks. Finally, we find that SO, SO2 and H2S havesignificant abundance jumps in the inner hot core of IRAS16293-2422and discuss the implications of the measured abundances.
Top co-authors
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Institutions
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2008–2011
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University of Bordeaux
Bordeaux, Aquitaine, France -
Université Bordeaux 1
Talence, Aquitaine, France
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2005
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The Ohio State University
Columbus, OH, USA
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