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49 results on '"Spezzano, S."'

2. Fractionation in young cores: Direct determinations of nitrogen and carbon fractionation in HCN.

Author

Jensen, S. S., Spezzano, S., Caselli, P., Sipilä, O., Redaelli, E., Giers, K., and Ferrer Asensio, J.

Subjects
*STELLAR evolution, *INTERSTELLAR medium, *STAR formation, *NITROGEN, *RADIATIVE transfer
Abstract

Context. Nitrogen fractionation is a powerful tracer of the chemical evolution during star and planet formation. It requires robust determinations of the nitrogen fractionation across different evolutionary stages. Aims. We aim to determine the 14N/15N and 12C/13C ratios for HCN in six starless and prestellar cores and to compare the results between the direct method using radiative transfer modeling and the indirect double isotope method, assuming a fixed 12C/13C ratio. Methods. We present IRAM observations of the HCN 1–0, HCN 3–2, HC15N 1–0 and H13CN 1–0 transitions toward six embedded cores. The 14N/15N ratio was derived using both the indirect double isotope method and directly through non-local thermodynamic equilibrium (NLTE) 1D radiative transfer modeling of the HCN emission. The latter also provides the 12C/13C ratio, which we compared to the local interstellar value. Results. The derived 14N/15N ratios using the indirect method are generally in the range of 300-550. This result could suggest an evolutionary trend in the nitrogen fractionation of HCN between starless cores and later stages of the star formation process. However, the direct method reveals lower fractionation ratios of around ~250, mainly resulting from a lower 12C/13C ratio in the range ~20–40, as compared to the local interstellar medium value of 68. Conclusions. This study reveals a significant difference between the nitrogen fractionation ratio in HCN derived using direct and indirect methods. This can influence the interpretation of the chemical evolution and reveal the pitfalls of the indirect double isotope method for fractionation studies. However, the direct method is challenging, as it requires well-constrained source models to produce accurate results. No trend in the nitrogen fractionation of HCN between earlier and later stages of the star formation process is evident when the results of the direct method are considered. [ABSTRACT FROM AUTHOR]

Published
2024
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3. Gas phase Elemental abundances in Molecular cloudS (GEMS). IX. Deuterated compounds of H2S in starless cores.

Author

Rodríguez-Baras, M., primary, Esplugues, G., additional, Fuente, A., additional, Spezzano, S., additional, Caselli, P., additional, Loison, J.C., additional, Roueff, E., additional, Navarro-Almaida, D., additional, Bachiller, R., additional, Martín-Doménech, R., additional, Jiménez-Serra, I., additional, Beitia-Antero, L., additional, and Le Gal, R., additional

Published
2023
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4. CoCCoA: Complex Chemistry in hot Cores with ALMA

Author

Chen, Y., primary, van Gelder, M. L., additional, Nazari, P., additional, Brogan, C. L., additional, van Dishoeck, E. F., additional, Linnartz, H., additional, Jørgensen, J. K., additional, Hunter, T. R., additional, Wilkins, O. H., additional, Blake, G. A., additional, Caselli, P., additional, Chuang, K.-J., additional, Codella, C., additional, Cooke, I., additional, Drozdovskaya, M. N., additional, Garrod, R. T., additional, Ioppolo, S., additional, Jin, M., additional, Kulterer, B. M., additional, Ligterink, N. F. W., additional, Lipnicky, A., additional, Loomis, R., additional, Rachid, M. G., additional, Spezzano, S., additional, and McGuire, B. A., additional

Published
2023
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14. Deuteration of c-C3H2 towards the pre-stellar core L1544

Author

Giers, K., primary, Spezzano, S., additional, Alves, F., additional, Caselli, P., additional, Redaelli, E., additional, Sipilä, O., additional, Ben Khalifa, M., additional, Wiesenfeld, L., additional, Brünken, S., additional, and Bizzocchi, L., additional

Published
2022
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15. SOLIS

Author

de A. Schutzer, A., primary, Rivera-Ortiz, P. R., additional, Lefloch, B., additional, Gusdorf, A., additional, Favre, C., additional, Segura-Cox, D., additional, López-Sepulcre, A., additional, Neri, R., additional, Ospina-Zamudio, J., additional, De Simone, M., additional, Codella, C., additional, Viti, S., additional, Podio, L., additional, Pineda, J., additional, O’Donoghue, R., additional, Ceccarelli, C., additional, Caselli, P., additional, Alves, F., additional, Bachiller, R., additional, Balucani, N., additional, Bianchi, E., additional, Bizzocchi, L., additional, Bottinelli, S., additional, Caux, E., additional, Chacón-Tanarro, A., additional, Dulieu, F., additional, Enrique-Romero, J., additional, Fontani, F., additional, Feng, S., additional, Holdship, J., additional, Jiménez-Serra, I., additional, Jaber Al-Edhari, A., additional, Kahane, C., additional, Lattanzi, V., additional, Oya, Y., additional, Punanova, A., additional, Rimola, A., additional, Sakai, N., additional, Spezzano, S., additional, Sims, I. R., additional, Taquet, V., additional, Testi, L., additional, Theulé, P., additional, Ugliengo, P., additional, Vastel, C., additional, Vasyunin, A. I., additional, Vazart, F., additional, Yamamoto, S., additional, and Witzel, A., additional

Published
2022
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16. Gas phase Elemental abundances in Molecular cloudS (GEMS)

Author

Esplugues, G., primary, Fuente, A., additional, Navarro-Almaida, D., additional, Rodríguez-Baras, M., additional, Majumdar, L., additional, Caselli, P., additional, Wakelam, V., additional, Roueff, E., additional, Bachiller, R., additional, Spezzano, S., additional, Rivière-Marichalar, P., additional, Martín-Doménech, R., additional, and Muñoz Caro, G. M., additional

Published
2022
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17. H2CS deuteration maps towards the pre-stellar core L1544

Author

Spezzano, S., primary, Sipilä, O., additional, Caselli, P., additional, Jensen, S. S., additional, Czakli, S., additional, Bizzocchi, L., additional, Chantzos, J., additional, Esplugues, G., additional, Fuente, A., additional, and Eisenhauer, F., additional

Published
2022
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18. Tracing the contraction of the pre-stellar core L1544 with HC17O+ J = 1–0 emission

Author

Asensio, J. Ferrer, Spezzano, S., Caselli, P., Alves, F. O., Sipilä, O., Redaelli, E., Bizzocchi, L., Lique, F., Mullins, A., Max-Planck-Institut für Extraterrestrische Physik (MPE), Scuola Normale Superiore di Pisa (SNS), Institut de Physique de Rennes (IPR), Université de Rennes (UR)-Centre National de la Recherche Scientifique (CNRS), and J.F.A., S.S., P.C., F.O.A., O.S, E.R. and L.B. gratefully acknowledge the support of the Max Planck Society.

Subjects
[PHYS]Physics [physics], radio lines: ISM, stars: formation, radiative transfer, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), FOS: Physical sciences, Astronomy and Astrophysics, Quantum dynamics, Molecular physics, Astrophysics - Astrophysics of Galaxies, ISM: clouds, ISM: molecules
Abstract

Context. Spectral line profiles of several molecules observed towards the pre-stellar core L1544 appear double-peaked. For abundant molecular species this line morphology has been linked to self-absorption. However, the physical process behind the double-peaked morphology for less abundant species is still under debate. Aims. In order to understand the cause behind the double-peaked spectra of optically thin transitions and their link to the physical structure of pre-stellar cores, we present high-sensitivity and high spectral resolution HC17O+ J =1−0 observations towards the dust peak in L1544. Methods. We observed the HC17O+(1−0) spectrum with the Institut de Radioastronomie Millimétrique (IRAM) 30 m telescope. By using state-of-the-art collisional rate coefficients, a physical model for the core and the fractional abundance profile of HC17O+, the hyperfine structure of this molecular ion is modelled for the first time with the radiative transfer code loc applied to the predicted chemical structure of a contracting pre-stellar core. We applied the same analysis to the chemically related C17O molecule. Results. The observed HC17O+(1−0) and C17O(1−0) lines were successfully reproduced with a non-local thermal equilibrium (LTE) radiative transfer model applied to chemical model predictions for a contracting pre-stellar core. An upscaled velocity profile (by 30%) is needed to reproduce the HC17O+(1−0) observations. Conclusions. The double peaks observed in the HC17O+(1−0) hyperfine components are due to the contraction motions at densities close to the critical density of the transition (~105 cm−3) and to the decreasing HCO+ fractional abundance towards the centre.

Published
2022

20. Tracing the contraction of the pre-stellar core L1544 with HC17O+J = 1–0 emission.

Author

Ferrer Asensio, J., Spezzano, S., Caselli, P., Alves, F. O., Sipilä, O., Redaelli, E., Bizzocchi, L., Lique, F., and Mullins, A.

Subjects
*ASTROCHEMISTRY, *MASS transfer coefficients, *THERMAL equilibrium, *HYPERFINE structure, *RADIATIVE transfer, *CHEMICAL models, *IONS, *IONIC structure
Abstract

Context. Spectral line profiles of several molecules observed towards the pre-stellar core L1544 appear double-peaked. For abundant molecular species this line morphology has been linked to self-absorption. However, the physical process behind the double-peaked morphology for less abundant species is still under debate. Aims. In order to understand the cause behind the double-peaked spectra of optically thin transitions and their link to the physical structure of pre-stellar cores, we present high-sensitivity and high spectral resolution HC17O+J =1−0 observations towards the dust peak in L1544. Methods. We observed the HC17O+(1−0) spectrum with the Institut de Radioastronomie Millimétrique (IRAM) 30 m telescope. By using state-of-the-art collisional rate coefficients, a physical model for the core and the fractional abundance profile of HC17O+, the hyperfine structure of this molecular ion is modelled for the first time with the radiative transfer code loc applied to the predicted chemical structure of a contracting pre-stellar core. We applied the same analysis to the chemically related C17O molecule. Results. The observed HC17O+(1−0) and C17O(1−0) lines were successfully reproduced with a non-local thermal equilibrium (LTE) radiative transfer model applied to chemical model predictions for a contracting pre-stellar core. An upscaled velocity profile (by 30%) is needed to reproduce the HC17O+(1−0) observations. Conclusions. The double peaks observed in the HC17O+(1−0) hyperfine components are due to the contraction motions at densities close to the critical density of the transition (~105 cm−3) and to the decreasing HCO+ fractional abundance towards the centre. [ABSTRACT FROM AUTHOR]

Published
2022
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22. Gas phase Elemental abundances in Molecular cloudS (GEMS)

Author

Rodríguez-Baras, M., primary, Fuente, A., additional, Riviére-Marichalar, P., additional, Navarro-Almaida, D., additional, Caselli, P., additional, Gerin, M., additional, Kramer, C., additional, Roueff, E., additional, Wakelam, V., additional, Esplugues, G., additional, García-Burillo, S., additional, Le Gal, R., additional, Spezzano, S., additional, Alonso-Albi, T., additional, Bachiller, R., additional, Cazaux, S., additional, Commercon, B., additional, Goicoechea, J. R., additional, Loison, J. C., additional, Treviño-Morales, S. P., additional, Roncero, O., additional, Jiménez-Serra, I., additional, Laas, J., additional, Hacar, A., additional, Kirk, J., additional, Lattanzi, V., additional, Martín-Doménech, R., additional, Muñoz-Caro, G., additional, Pineda, J. E., additional, Tercero, B., additional, Ward-Thompson, D., additional, Tafalla, M., additional, Marcelino, N., additional, Malinen, J., additional, Friesen, R., additional, and Giuliano, B. M., additional

Published
2021
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23. Gas phase Elemental abundances in Molecular cloudS (GEMS)

Author

Bulut, N., primary, Roncero, O., additional, Aguado, A., additional, Loison, J.-C., additional, Navarro-Almaida, D., additional, Wakelam, V., additional, Fuente, A., additional, Roueff, E., additional, Le Gal, R., additional, Caselli, P., additional, Gerin, M., additional, Hickson, K. M., additional, Spezzano, S., additional, Riviére-Marichalar, P., additional, Alonso-Albi, T., additional, Bachiller, R., additional, Jiménez-Serra, I., additional, Kramer, C., additional, Tercero, B., additional, Rodriguez-Baras, M., additional, García-Burillo, S., additional, Goicoechea, J. R., additional, Treviño-Morales, S. P., additional, Esplugues, G., additional, Cazaux, S., additional, Commercon, B., additional, Laas, J., additional, Kirk, J., additional, Lattanzi, V., additional, Martín-Doménech, R., additional, Muñoz-Caro, G., additional, Pineda, J., additional, Ward-Thompson, D., additional, Tafalla, M., additional, Marcelino, N., additional, Malinen, J., additional, Friesen, R., additional, Giuliano, B. M., additional, Agúndez, M., additional, and Hacar, A., additional

Published
2021
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24. Seeds of Life in Space (SOLIS)

Author

Benedettini, M., primary, Viti, S., additional, Codella, C., additional, Ceccarelli, C., additional, Neri, R., additional, López-Sepulcre, A., additional, Bianchi, E., additional, Busquet, G., additional, Caselli, P., additional, Fontani, F., additional, Lefloch, B., additional, Podio, L., additional, Spezzano, S., additional, and Vastel, C., additional

Published
2021
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26. Seeds of Life in Space (SOLIS)

Author

Spezzano, S., primary, Codella, C., additional, Podio, L., additional, Ceccarelli, C., additional, Caselli, P., additional, Neri, R., additional, and López-Sepulcre, A., additional

Published
2020
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27. Seeds of Life in Space (SOLIS)

Author

Taquet, V., primary, Codella, C., additional, De Simone, M., additional, López-Sepulcre, A., additional, Pineda, J. E., additional, Segura-Cox, D., additional, Ceccarelli, C., additional, Caselli, P., additional, Gusdorf, A., additional, Persson, M. V., additional, Alves, F., additional, Caux, E., additional, Favre, C., additional, Fontani, F., additional, Neri, R., additional, Oya, Y., additional, Sakai, N., additional, Vastel, C., additional, Yamamoto, S., additional, Bachiller, R., additional, Balucani, N., additional, Bianchi, E., additional, Bizzocchi, L., additional, Chacón-Tanarro, A., additional, Dulieu, F., additional, Enrique-Romero, J., additional, Feng, S., additional, Holdship, J., additional, Lefloch, B., additional, Jaber Al-Edhari, A., additional, Jiménez-Serra, I., additional, Kahane, C., additional, Lattanzi, V., additional, Ospina-Zamudio, J., additional, Podio, L., additional, Punanova, A., additional, Rimola, A., additional, Sims, I. R., additional, Spezzano, S., additional, Testi, L., additional, Theulé, P., additional, Ugliengo, P., additional, Vasyunin, A. I., additional, Vazart, F., additional, Viti, S., additional, and Witzel, A., additional

Published
2020
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28. Seeds of Life in Space (SOLIS)

Author

Codella, C., primary, Ceccarelli, C., additional, Bianchi, E., additional, Balucani, N., additional, Podio, L., additional, Caselli, P., additional, Feng, S., additional, Lefloch, B., additional, López-Sepulcre, A., additional, Neri, R., additional, Spezzano, S., additional, and De Simone, M., additional

Published
2020
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29. Seeds of Life in Space (SOLIS)

Author

Favre, C., primary, Vastel, C., additional, Jimenez-Serra, I., additional, Quénard, D., additional, Caselli, P., additional, Ceccarelli, C., additional, Chacón-Tanarro, A., additional, Fontani, F., additional, Holdship, J., additional, Oya, Y., additional, Punanova, A., additional, Sakai, N., additional, Spezzano, S., additional, Yamamoto, S., additional, Neri, R., additional, López-Sepulcre, A., additional, Alves, F., additional, Bachiller, R., additional, Balucani, N., additional, Bianchi, E., additional, Bizzocchi, L., additional, Codella, C., additional, Caux, E., additional, De Simone, M., additional, Enrique Romero, J., additional, Dulieu, F., additional, Feng, S., additional, Jaber Al-Edhari, A., additional, Lefloch, B., additional, Ospina-Zamudio, J., additional, Pineda, J., additional, Podio, L., additional, Rimola, A., additional, Segura-Cox, D., additional, Sims, I. R., additional, Taquet, V., additional, Testi, L., additional, Theulé, P., additional, Ugliengo, P., additional, Vasyunin, A. I., additional, Vazart, F., additional, Viti, S., additional, and Witzel, A., additional

Published
2020
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32. Mapping deuterated methanol toward L1544

Author

Chacón-Tanarro, A., primary, Caselli, P., additional, Bizzocchi, L., additional, Pineda, J. E., additional, Sipilä, O., additional, Vasyunin, A., additional, Spezzano, S., additional, Punanova, A., additional, Giuliano, B. M., additional, and Lattanzi, V., additional

Published
2019
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36. Seeds of Life in Space (SOLIS)

Author

Fontani, F., primary, Ceccarelli, C., additional, Favre, C., additional, Caselli, P., additional, Neri, R., additional, Sims, I. R., additional, Kahane, C., additional, Alves, F. O., additional, Balucani, N., additional, Bianchi, E., additional, Caux, E., additional, Jaber Al-Edhari, A., additional, Lopez-Sepulcre, A., additional, Pineda, J. E., additional, Bachiller, R., additional, Bizzocchi, L., additional, Bottinelli, S., additional, Chacon-Tanarro, A., additional, Choudhury, R., additional, Codella, C., additional, Coutens, A., additional, Dulieu, F., additional, Feng, S., additional, Rimola, A., additional, Hily-Blant, P., additional, Holdship, J., additional, Jimenez-Serra, I., additional, Laas, J., additional, Lefloch, B., additional, Oya, Y., additional, Podio, L., additional, Pon, A., additional, Punanova, A., additional, Quenard, D., additional, Sakai, N., additional, Spezzano, S., additional, Taquet, V., additional, Testi, L., additional, Theulé, P., additional, Ugliengo, P., additional, Vastel, C., additional, Vasyunin, A. I., additional, Viti, S., additional, Yamamoto, S., additional, and Wiesenfeld, L., additional

Published
2017
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37. Seeds of Life in Space (SOLIS)

Author

Codella, C., primary, Ceccarelli, C., additional, Caselli, P., additional, Balucani, N., additional, Barone, V., additional, Fontani, F., additional, Lefloch, B., additional, Podio, L., additional, Viti, S., additional, Feng, S., additional, Bachiller, R., additional, Bianchi, E., additional, Dulieu, F., additional, Jiménez-Serra, I., additional, Holdship, J., additional, Neri, R., additional, Pineda, J. E., additional, Pon, A., additional, Sims, I., additional, Spezzano, S., additional, Vasyunin, A. I., additional, Alves, F., additional, Bizzocchi, L., additional, Bottinelli, S., additional, Caux, E., additional, Chacón-Tanarro, A., additional, Choudhury, R., additional, Coutens, A., additional, Favre, C., additional, Hily-Blant, P., additional, Kahane, C., additional, Jaber Al-Edhari, A., additional, Laas, J., additional, López-Sepulcre, A., additional, Ospina, J., additional, Oya, Y., additional, Punanova, A., additional, Puzzarini, C., additional, Quenard, D., additional, Rimola, A., additional, Sakai, N., additional, Skouteris, D., additional, Taquet, V., additional, Testi, L., additional, Theulé, P., additional, Ugliengo, P., additional, Vastel, C., additional, Vazart, F., additional, Wiesenfeld, L., additional, and Yamamoto, S., additional

Published
2017
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39. High-sensitivity maps of molecular ions in L1544: I. Deuteration of N2H+ and HCO+ and primary evidence of N2D+ depletion.

Author

Redaelli, E., Bizzocchi, L., Caselli, P., Sipilä, O., Lattanzi, V., Giuliano, B. M., and Spezzano, S.

Subjects
IONS, DEUTERATION, DEUTERIUM, CHEMICAL models, RADIATIVE transfer, ASTROCHEMISTRY, THERMODYNAMIC equilibrium
Abstract

Context. The deuterium fraction in low-mass prestellar cores is a good diagnostic indicator of the initial phases of star formation, and is also a fundamental quantity to infer the ionisation degree in these objects. Aims. With the analysis of multiple transitions of N2H+, N2D+, HC18O+, and DCO+ we are able to determine the molecular column density maps and the deuterium fraction in N2H+ and HCO+ toward the prototypical prestellar core L1544. This is the preliminary step to derive the ionisation degree in the source. Methods. We used a non-local thermodynamic equilibrium (non-LTE) radiative transfer code combined with the molecular abundances derived from a chemical model to infer the excitation conditions of all the observed transitions. This allowed us to derive reliable maps of the column density of each molecule. The ratio between the column density of a deuterated species and its non-deuterated counterpart gives the sought-after deuteration level. Results. The non-LTE analysis confirms that, for the molecules analysed, higher-J transitions are characterised by excitation temperatures that are ≈1–2 K lower than those of the lower-J transitions. The chemical model that provides the best fit to the observational data predicts the depletion of N2H+ and to a lesser extent of N2D+ in the innermost region. The peak values for the deuterium fraction that we find are D/HN2H+ = 0.26−0.14+0.15 ${\textrm{D/H}_{\textrm{N}_2\textrm{H}^+}} = 0.26^{+0.15}_{-0.14}$ D/H N 2 H + = 0.26 − 0.14 + 0.15 and D/HHCO+=0.035−0.012+0.015 $\mathrm{\textrm{D/H}_{\textrm{HCO}^+}} = 0.035^{+0.015}_{-0.012}$ D/H HCO + = 0.035 − 0.012 + 0.015 , in good agreement with previous estimates in the source. [ABSTRACT FROM AUTHOR]

Published
2019
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43. A 1.3 cm line survey toward Orion KL

Author

Gong, Y., primary, Henkel, C., additional, Thorwirth, S., additional, Spezzano, S., additional, Menten, K. M., additional, Walmsley, C. M., additional, Wyrowski, F., additional, Mao, R. Q., additional, and Klein, B., additional

Published
2015
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44. A 1.3 cm line survey toward IRC +10216

Author

Gong, Y., primary, Henkel, C., additional, Spezzano, S., additional, Thorwirth, S., additional, Menten, K. M., additional, Wyrowski, F., additional, Mao, R. Q., additional, and Klein, B., additional

Published
2015
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45. Accurate sub-millimetre rest frequencies for HOCO+ and DOCO+ ions.

Author

Bizzocchi, L., Lattanzi, V., Laas, J., Spezzano, S., Giuliano, B. M., Prudenzano, D., Endres, C., Sipilä, O., and Caselli, P.

Subjects
PROTOSTARS, POLAR molecules, PLASMA confinement, ASTROCHEMISTRY, IONS, EXCITED states, INTERSTELLAR medium
Abstract

Context. HOCO+ is a polar molecule that represents a useful proxy for its parent molecule CO2, which is not directly observable in the cold interstellar medium. This cation has been detected towards several lines of sight, including massive star forming regions, protostars, and cold cores. Despite the obvious astrochemical relevance, protonated CO2 and its deuterated variant, DOCO+, still lack an accurate spectroscopic characterisation. Aims. The aim of this work is to extend the study of the ground-state pure rotational spectra of HOCO+ and DOCO+ well into the sub-millimetre region. Methods. Ground-state transitions have been recorded in the laboratory using a frequency-modulation absorption spectrometer equipped with a free-space glow-discharge cell. The ions were produced in a low-density, magnetically confined plasma generated in a suitable gas mixture. The ground-state spectra of HOCO+ and DOCO+ have been investigated in the 213-967 GHz frequency range; 94 new rotational transitions have been detected. Additionally, 46 line positions taken from the literature have been accurately remeasured. Results. The newly measured lines have significantly enlarged the available data sets for HOCO+ and DOCO+, thus enabling the determination of highly accurate rotational and centrifugal distortion parameters. Our analysis shows that all HOCO+ lines with Kα ≥ &#; are perturbed by a ro-vibrational interaction that couples the ground state with the v5 = 1 vibrationally excited state. This resonance has been explicitly treated in the analysis in order to obtain molecular constants with clear physical meaning. Conclusions. The improved sets of spectroscopic parameters provide enhanced lists of very accurate sub-millimetre rest frequencies of HOCO+ and DOCO+ for astrophysical applications. These new data challenge a recent tentative identification of DOCO+ towards a pre-stellar core. [ABSTRACT FROM AUTHOR]

Published
2017
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47. Understanding the C3H2 cyclic-to-linear ratio in L1544.

Author

Sipilä, O., Spezzano, S., and Caselli, P.

Subjects
*CYCLOPROPENYLIDENE, *ASTROCHEMISTRY, *CHEMICAL models, *SIMULATION methods & models, *LINEAR systems
Abstract

Aims. We aim to understand the high cyclic-to-linear C3H2 ratio (32 ± 4) that has been observed toward L1544. Methods. We combined a gas-grain chemical model with a physical model for L1544 to simulate the column densities of cyclic and linear C3H2 observed toward L1544. The most important reactions for the formation and destruction of both forms of C3H2 were identified, and their relative rate coefficients were varied to find the best match to the observations. Results. We find that the ratio of the rate coefficients of C3H3++e- → C3H2+H for cyclic and linear C3H2 must be ~20 to reproduce the observations, depending on the branching ratios assumed for the C3H3++e- → C3H + H2 reaction. In current astrochemical networks it is assumed that cyclic and linear C3H2 are formed in a 1:1 ratio in the aforementioned reactions. Laboratory studies and/or theoretical calculations are needed to confirm the results of our chemical modeling, which is based on observational constraints. [ABSTRACT FROM AUTHOR]

Published
2016
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48. Seeds of Life in Space (SOLIS): VI. Chemical evolution of sulfuretted species along the outflows driven by the low-mass protostellar binary NGC 1333-IRAS4A

Author

V. Taquet, C. Codella, M. De Simone, A. López-Sepulcre, J. E. Pineda, D. Segura-Cox, C. Ceccarelli, P. Caselli, A. Gusdorf, M. V. Persson, F. Alves, E. Caux, C. Favre, F. Fontani, R. Neri, Y. Oya, N. Sakai, C. Vastel, S. Yamamoto, R. Bachiller, N. Balucani, E. Bianchi, L. Bizzocchi, A. Chacón-Tanarro, F. Dulieu, J. Enrique-Romero, S. Feng, J. Holdship, B. Lefloch, A. Jaber Al-Edhari, I. Jiménez-Serra, C. Kahane, V. Lattanzi, J. Ospina-Zamudio, L. Podio, A. Punanova, A. Rimola, I. R. Sims, S. Spezzano, L. Testi, P. Theulé, P. Ugliengo, A. I. Vasyunin, F. Vazart, S. Viti, A. Witzel, Istituto Nazionale di Astrofisica (INAF), Institut de Planétologie et d'Astrophysique de Grenoble (IPAG), Centre National d'Études Spatiales [Toulouse] (CNES)-Observatoire des Sciences de l'Univers de Grenoble (OSUG ), Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA), Max Planck Institute for Extraterrestrial Physics (MPE), Max-Planck-Gesellschaft, Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA (UMR_8112)), Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-CY Cergy Paris Université (CY), Chalmers University of Technology [Göteborg], Centre National d'Études Spatiales [Toulouse] (CNES), Institut de recherche en astrophysique et planétologie (IRAP), Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), Institut de RadioAstronomie Millimétrique (IRAM), Centre National de la Recherche Scientifique (CNRS), The University of Tokyo (UTokyo), RIKEN - Institute of Physical and Chemical Research [Japon] (RIKEN), Instituto Geografico Nacional (IGN), National Astronomical Observatories [Beijing] (NAOC), Chinese Academy of Sciences [Beijing] (CAS), University College of London [London] (UCL), Spanish National Research Council (CSIC), Ural Federal University [Ekaterinburg] (UrFU), Departament de Química [Barcelona] (UAB), Universitat Autònoma de Barcelona (UAB), Institut de Physique de Rennes (IPR), Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS), European Southern Observatory (ESO), Physique des interactions ioniques et moléculaires (PIIM), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS), Università degli studi di Torino (UNITO), IRAM PdBI/NOEMA Interferometer [V05B, V010, U003, L15AA], MPG (Germany)Max Planck Society, IGN (Spain), European Union's Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grantEuropean Union (EU) [664931], PRIN-INAF 2016 'The Cradle of Life -GENESIS-SKA (General Conditions in Early Planetary Systems for the rise of life with SKA)', European Research Council (ERC) under the European Union's Horizon 2020 research and innovation programmeEuropean Research Council (ERC) [741002], European MARIE SKLODOWSKA-CURIE ACTIONS under the European Union's Horizon 2020 research and innovation programme [811312], French National Research Agency of the 'Origin of Life' project of the Universite Grenoble-AlpesFrench National Research Agency (ANR) [ANR-15-IDEX-02], INSU/CNRS (France)Centre National de la Recherche Scientifique (CNRS), Ceccarelli, C. [0000-0001-9664-6292], Balucani, N. [0000-0001-5121-5683], Rimola, A. [0000-0002-9637-4554], Al Edhari, A. J. [0000-0003-4089-841X], De Oliveira Alves, F. [0000-0002-7945-064X], Lefloch, B. [0000-0002-9397-3826], Persson, M. V. [0000-0002-1100-5734], Bachiller, R. [0000-0002-5331-5386], Pineda, J. [0000-0002-3972-1978], Segura Cox, D. [0000-0003-3172-6763], IRAM PdBI/NOEMA Interferometer, V05B V010 U003 L15AA, Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Météo-France -Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Météo-France, Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique et Atmosphères = Laboratory for Studies of Radiation and Matter in Astrophysics and Atmospheres (LERMA), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-CY Cergy Paris Université (CY), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Université de Rennes (UR)-Centre National de la Recherche Scientifique (CNRS), Università degli studi di Torino = University of Turin (UNITO), ANR-15-IDEX-0002,UGA,IDEX UGA(2015), Unidad de Excelencia Científica María de Maeztu Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, MDM-2017-0737, Agence Nationale de la Recherche (ANR), European Research Council (ERC), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-CY Cergy Paris Université (CY), Taquet V., Codella C., De Simone M., Lopez-Sepulcre A., Pineda J.E., Segura-Cox D., Ceccarelli C., Caselli P., Gusdorf A., Persson M.V., Alves F., Caux E., Favre C., Fontani F., Neri R., Oya Y., Sakai N., Vastel C., Yamamoto S., Bachiller R., Balucani N., Bianchi E., Bizzocchi L., Chacon-Tanarro A., Dulieu F., Enrique-Romero J., Feng S., Holdship J., Lefloch B., Jaber Al-Edhari A., Jimenez-Serra I., Kahane C., Lattanzi V., Ospina-Zamudio J., Podio L., Punanova A., Rimola A., Sims I.R., Spezzano S., Testi L., Theule P., Ugliengo P., Vasyunin A.I., Vazart F., Viti S., and Witzel A.

Subjects
MILLIMETER ARRAYS, Binary number, CHEMICAL EVOLUTION, ISM: molecule, Astrophysics, Space (mathematics), 01 natural sciences, ISM: abundances, CHEMICAL CONDITIONS, ISM jets and outflows, ABUNDANCES [ISM], jets and outflows -ISM, CHEMICAL DIFFERENTIATION, 010303 astronomy & astrophysics, ISM abundances, Astrochemistry, Physics, [PHYS]Physics [physics], ASTROCHEMISTRY, Shock (fluid dynamics), INTERSTELLAR ICE, SUBMILLIMETRE TELESCOPES, NGC 1333-IRAS4A, ISM: abundance, ISM: molecules, stars formation, Radial velocity, ISM: jets and outflows, ISM individual objects NGC1333-IRAS4A, ISM: individual objects: NGC 1333-IRAS4A, CHEMICAL HISTORY, Low Mass, molecules -stars, Stars: formation, individual objects, JETS AND OUTFLOWS [ISM], FOS: Physical sciences, Context (language use), INDIVIDUAL OBJECTS: NGC 1333-IRAS4A [ISM], SILICON COMPOUNDS, SULFUR DIOXIDE, ISM molecules, astrochemistry -ISM, FORMATION [STARS], 0103 physical sciences, Protostar, ISM: jets and outflow, formation -ISM, 010308 nuclear & particles physics, Astronomy and Astrophysics, Astrophysics - Astrophysics of Galaxies, abundances -ISM, 13. Climate action, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), MOLECULES [ISM], Outflow, MOLECULAR OUTFLOWS, STARS
Abstract

Context. Low-mass protostars drive powerful molecular outflows that can be observed with millimetre and submillimetre telescopes. Various sulfuretted species are known to be bright in shocks and could be used to infer the physical and chemical conditions throughout the observed outflows. Aims. The evolution of sulfur chemistry is studied along the outflows driven by the NGC 1333-IRAS4A protobinary system located in the Perseus cloud to constrain the physical and chemical processes at work in shocks. Methods. We observed various transitions from OCS, CS, SO, and SO2 towards NGC 1333-IRAS4A in the 1.3, 2, and 3 mm bands using the IRAM NOrthern Extended Millimeter Array and we interpreted the observations through the use of the Paris-Durham shock model. Results. The targeted species clearly show different spatial emission along the two outflows driven by IRAS4A. OCS is brighter on small and large scales along the south outflow driven by IRAS4A1, whereas SO2 is detected rather along the outflow driven by IRAS4A2 that is extended along the north east-south west direction. SO is detected at extremely high radial velocity up to + 25 km s-1 relative to the source velocity, clearly allowing us to distinguish the two outflows on small scales. Column density ratio maps estimated from a rotational diagram analysis allowed us to confirm a clear gradient of the OCS/SO2 column density ratio between the IRAS4A1 and IRAS4A2 outflows. Analysis assuming non Local Thermodynamic Equilibrium of four SO2 transitions towards several SiO emission peaks suggests that the observed gas should be associated with densities higher than 105 cm-3 and relatively warm (T > 100 K) temperatures in most cases. Conclusions. The observed chemical differentiation between the two outflows of the IRAS4A system could be explained by a different chemical history. The outflow driven by IRAS4A1 is likely younger and more enriched in species initially formed in interstellar ices, such as OCS, and recently sputtered into the shock gas. In contrast, the longer and likely older outflow triggered by IRAS4A2 is more enriched in species that have a gas phase origin, such as SO2., With funding from the Spanish government through the "María de Maeztu Unit of Excellence" accreditation (MDM-2017-0737)

Published
2020

49. Mapping deuterated methanol toward L1544: I. Deuterium fraction and comparison with modeling

Author

A. Vasyunin, Barbara M. Giuliano, Ana Chacón-Tanarro, Paola Caselli, Anna Punanova, Luca Bizzocchi, Jaime E. Pineda, Valerio Lattanzi, Silvia Spezzano, Olli Sipilä, Chacon-Tanarro A., Caselli P., Bizzocchi L., Pineda J.E., Sipila O., Vasyunin A., Spezzano S., Punanova A., Giuliano B.M., and Lattanzi V.

Subjects
INDIVIDUAL OBJECTS [ISM], Astrochemistry, Stars: formation, DEUTERIUM, Analytical chemistry, Formaldehyde, FOS: Physical sciences, Context (language use), DUST, Astrophysics, ISM: molecule, 01 natural sciences, INDIVIDUAL OBJECTS: L1544 [ISM], chemistry.chemical_compound, MOLECULES, ISM: cloud, Desorption, FORMATION [STARS], 0103 physical sciences, Isotopologue, FORMALDEHYDE, 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), Physics, ASTROCHEMISTRY, CHEMICAL ANALYSIS, 010308 nuclear & particles physics, Astronomy and Astrophysics, Astrophysics - Astrophysics of Galaxies, CLOUDS [ISM], chemistry, Deuterium, Astrophysics - Solar and Stellar Astrophysics, 13. Climate action, Space and Planetary Science, ISM: individual objects: L1544, Astrophysics of Galaxies (astro-ph.GA), MOLECULES [ISM], Deuterated methanol, METHANOL, Methanol, STARS
Abstract

The study of deuteration in pre-stellar cores is important to understand the physical and chemical initial conditions in the process of star formation. In particular, observations toward pre-stellar cores of methanol and deuterated methanol, solely formed on the surface of dust grains, may provide useful insights on surface processes at low temperatures. Here we analyze maps of CO, methanol, formaldehyde and their deuterated isotopologues toward a well-known pre-stellar core. This study allows us to test current gas-dust chemical models. Single-dish observations of CH$_3$OH, CH$_2$DOH, H$_2$CO, H$_2\,^{13}$CO, HDCO, D$_2$CO and C$^{17}$O toward the prototypical pre-stellar core L1544 were performed at the IRAM 30 m telescope. We analyze their column densities, distributions, and compare these observations with gas-grain chemical models. The maximum deuterium fraction derived for methanol is [CH$_2$DOH]/[CH$_3$OH] $\sim$ 0.08$\pm$0.02, while the measured deuterium fractions of formaldehyde at the dust peak are [HDCO]/[H$_2$CO] $\sim$ 0.03$\pm$0.02, [D$_2$CO]/[H$_2$CO] $\sim$ 0.04$\pm$0.03 and [D$_2$CO]/[HDCO] $\sim$ 1.2$\pm$0.3. Observations differ significantly from the predictions of models, finding discrepancies between a factor of 10 and a factor of 100 in most cases. It is clear though that to efficiently produce methanol on the surface of dust grains, quantum tunneling diffusion of H atoms must be switched on. It also appears that the currently adopted reactive desorption efficiency of methanol is overestimated and/or that abstraction reactions play an important role. More laboratory work is needed to shed light on the chemistry of methanol, an important precursor of complex organic molecules in space., Accepted for publication in A&A

Published
2019

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