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31 results on '"Redaelli E"'

8. First light of BEaTriX, the new testing facility for the modular X-ray optics of the ATHENA mission

Author

Basso, S., primary, Salmaso, B., additional, Spiga, D., additional, Ghigo, M., additional, Vecchi, G., additional, Sironi, G., additional, Cotroneo, V., additional, Conconi, P., additional, Redaelli, E., additional, Bianco, A., additional, Pareschi, G., additional, Tagliaferri, G., additional, Sisana, D., additional, Pelliciari, C., additional, Fiorini, M., additional, Incorvaia, S., additional, Uslenghi, M., additional, Paoletti, L., additional, Ferrari, C., additional, Lolli, R., additional, Zappettini, A., additional, del Rio, M. Sanchez, additional, Parodi, G., additional, Burwitz, V., additional, Rukdee, S., additional, Hartner, G., additional, Müller, T., additional, Schmidt, T., additional, Langmeier, A., additional, Della Monica Ferreira, D., additional, Massahi, S., additional, Gellert, N. C., additional, Christensen, F., additional, Bavdaz, M., additional, Ferreira, I., additional, Collon, M., additional, Vacanti, G., additional, and Barrière, N. M., additional

Published
2022
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9. 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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10. 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
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15. ESPRESSO high-resolution transmission spectroscopy of WASP-76 b

Author

Tabernero, H. M., primary, Zapatero Osorio, M. R., additional, Allart, R., additional, Borsa, F., additional, Casasayas-Barris, N., additional, Demangeon, O., additional, Ehrenreich, D., additional, Lillo-Box, J., additional, Lovis, C., additional, Pallé, E., additional, Sousa, S. G., additional, Rebolo, R., additional, Santos, N. C., additional, Pepe, F., additional, Cristiani, S., additional, Adibekyan, V., additional, Allende Prieto, C., additional, Alibert, Y., additional, Barros, S. C. C., additional, Bouchy, F., additional, Bourrier, V., additional, D’Odorico, V., additional, Dumusque, X., additional, Faria, J. P., additional, Figueira, P., additional, Génova Santos, R., additional, González Hernández, J. I., additional, Hojjatpanah, S., additional, Lo Curto, G., additional, Lavie, B., additional, Martins, C. J. A. P., additional, Martins, J. H. C., additional, Mehner, A., additional, Micela, G., additional, Molaro, P., additional, Nunes, N. J., additional, Poretti, E., additional, Seidel, J. V., additional, Sozzetti, A., additional, Suárez Mascareño, A., additional, Udry, S., additional, Aliverti, M., additional, Affolter, M., additional, Alves, D., additional, Amate, M., additional, Avila, G., additional, Bandy, T., additional, Benz, W., additional, Bianco, A., additional, Broeg, C., additional, Cabral, A., additional, Conconi, P., additional, Coelho, J., additional, Cumani, C., additional, Deiries, S., additional, Dekker, H., additional, Delabre, B., additional, Fragoso, A., additional, Genoni, M., additional, Genolet, L., additional, Hughes, I., additional, Knudstrup, J., additional, Kerber, F., additional, Landoni, M., additional, Lizon, J. L., additional, Maire, C., additional, Manescau, A., additional, Di Marcantonio, P., additional, Mégevand, D., additional, Monteiro, M., additional, Moschetti, M., additional, Mueller, E., additional, Modigliani, A., additional, Oggioni, L., additional, Oliveira, A., additional, Pariani, G., additional, Pasquini, L., additional, Rasilla, J. L., additional, Redaelli, E., additional, Riva, M., additional, Santana-Tschudi, S., additional, Santin, P., additional, Santos, P., additional, Segovia, A., additional, Sosnowska, D., additional, Spanò, P., additional, Tenegi, F., additional, Iwert, O., additional, Zanutta, A., additional, and Zerbi, F., additional

Published
2021
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16. ESPRESSO at VLT

Author

Pepe, F., primary, Cristiani, S., additional, Rebolo, R., additional, Santos, N. C., additional, Dekker, H., additional, Cabral, A., additional, Di Marcantonio, P., additional, Figueira, P., additional, Lo Curto, G., additional, Lovis, C., additional, Mayor, M., additional, Mégevand, D., additional, Molaro, P., additional, Riva, M., additional, Zapatero Osorio, M. R., additional, Amate, M., additional, Manescau, A., additional, Pasquini, L., additional, Zerbi, F. M., additional, Adibekyan, V., additional, Abreu, M., additional, Affolter, M., additional, Alibert, Y., additional, Aliverti, M., additional, Allart, R., additional, Allende Prieto, C., additional, Álvarez, D., additional, Alves, D., additional, Avila, G., additional, Baldini, V., additional, Bandy, T., additional, Barros, S. C. C., additional, Benz, W., additional, Bianco, A., additional, Borsa, F., additional, Bourrier, V., additional, Bouchy, F., additional, Broeg, C., additional, Calderone, G., additional, Cirami, R., additional, Coelho, J., additional, Conconi, P., additional, Coretti, I., additional, Cumani, C., additional, Cupani, G., additional, D’Odorico, V., additional, Damasso, M., additional, Deiries, S., additional, Delabre, B., additional, Demangeon, O. D. S., additional, Dumusque, X., additional, Ehrenreich, D., additional, Faria, J. P., additional, Fragoso, A., additional, Genolet, L., additional, Genoni, M., additional, Génova Santos, R., additional, González Hernández, J. I., additional, Hughes, I., additional, Iwert, O., additional, Kerber, F., additional, Knudstrup, J., additional, Landoni, M., additional, Lavie, B., additional, Lillo-Box, J., additional, Lizon, J.-L., additional, Maire, C., additional, Martins, C. J. A. P., additional, Mehner, A., additional, Micela, G., additional, Modigliani, A., additional, Monteiro, M. A., additional, Monteiro, M. J. P. F. G., additional, Moschetti, M., additional, Murphy, M. T., additional, Nunes, N., additional, Oggioni, L., additional, Oliveira, A., additional, Oshagh, M., additional, Pallé, E., additional, Pariani, G., additional, Poretti, E., additional, Rasilla, J. L., additional, Rebordão, J., additional, Redaelli, E. M., additional, Santana Tschudi, S., additional, Santin, P., additional, Santos, P., additional, Ségransan, D., additional, Schmidt, T. M., additional, Segovia, A., additional, Sosnowska, D., additional, Sozzetti, A., additional, Sousa, S. G., additional, Spanò, P., additional, Suárez Mascareño, A., additional, Tabernero, H., additional, Tenegi, F., additional, Udry, S., additional, and Zanutta, A., additional

Published
2021
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18. A precise architecture characterization of theπMensae planetary system

Author

Damasso, M., primary, Sozzetti, A., additional, Lovis, C., additional, Barros, S. C. C., additional, Sousa, S. G., additional, Demangeon, O. D. S., additional, Faria, J. P., additional, Lillo-Box, J., additional, Cristiani, S., additional, Pepe, F., additional, Rebolo, R., additional, Santos, N. C., additional, Zapatero Osorio, M. R., additional, González Hernández, J. I., additional, Amate, M., additional, Pasquini, L., additional, Zerbi, F. M., additional, Adibekyan, V., additional, Abreu, M., additional, Affolter, M., additional, Alibert, Y., additional, Aliverti, M., additional, Allart, R., additional, Allende Prieto, C., additional, Álvarez, D., additional, Alves, D., additional, Avila, G., additional, Baldini, V., additional, Bandy, T., additional, Benz, W., additional, Bianco, A., additional, Borsa, F., additional, Bossini, D., additional, Bourrier, V., additional, Bouchy, F., additional, Broeg, C., additional, Cabral, A., additional, Calderone, G., additional, Cirami, R., additional, Coelho, J., additional, Conconi, P., additional, Coretti, I., additional, Cumani, C., additional, Cupani, G., additional, D’Odorico, V., additional, Deiries, S., additional, Dekker, H., additional, Delabre, B., additional, Di Marcantonio, P., additional, Dumusque, X., additional, Ehrenreich, D., additional, Figueira, P., additional, Fragoso, A., additional, Genolet, L., additional, Genoni, M., additional, Génova Santos, R., additional, Hughes, I., additional, Iwert, O., additional, Kerber, F., additional, Knudstrup, J., additional, Landoni, M., additional, Lavie, B., additional, Lizon, J.-L., additional, Lo Curto, G., additional, Maire, C., additional, Martins, C. J. A. P., additional, Mégevand, D., additional, Mehner, A., additional, Micela, G., additional, Modigliani, A., additional, Molaro, P., additional, Monteiro, M. A., additional, Monteiro, M. J. P. F. G., additional, Moschetti, M., additional, Mueller, E., additional, Murphy, M. T., additional, Nunes, N., additional, Oggioni, L., additional, Oliveira, A., additional, Oshagh, M., additional, Pallé, E., additional, Pariani, G., additional, Poretti, E., additional, Rasilla, J. L., additional, Rebordão, J., additional, Redaelli, E. M., additional, Riva, M., additional, Santana Tschudi, S., additional, Santin, P., additional, Santos, P., additional, Ségransan, D., additional, Schmidt, T. M., additional, Segovia, A., additional, Sosnowska, D., additional, Spanò, P., additional, Suárez Mascareño, A., additional, Tabernero, H., additional, Tenegi, F., additional, Udry, S., additional, and Zanutta, A., additional

Published
2020
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19. Characterization of the K2-38 planetary system

Author

Toledo-Padrón, B., primary, Lovis, C., additional, Suárez Mascareño, A., additional, Barros, S. C. C., additional, González Hernández, J. I., additional, Sozzetti, A., additional, Bouchy, F., additional, Zapatero Osorio, M. R., additional, Rebolo, R., additional, Cristiani, S., additional, Pepe, F. A., additional, Santos, N. C., additional, Sousa, S. G., additional, Tabernero, H. M., additional, Lillo-Box, J., additional, Bossini, D., additional, Adibekyan, V., additional, Allart, R., additional, Damasso, M., additional, D’Odorico, V., additional, Figueira, P., additional, Lavie, B., additional, Lo Curto, G., additional, Mehner, A., additional, Micela, G., additional, Modigliani, A., additional, Nunes, N. J., additional, Pallé, E., additional, Abreu, M., additional, Affolter, M., additional, Alibert, Y., additional, Aliverti, M., additional, Allende Prieto, C., additional, Alves, D., additional, Amate, M., additional, Avila, G., additional, Baldini, V., additional, Bandy, T., additional, Benatti, S., additional, Benz, W., additional, Bianco, A., additional, Broeg, C., additional, Cabral, A., additional, Calderone, G., additional, Cirami, R., additional, Coelho, J., additional, Conconi, P., additional, Coretti, I., additional, Cumani, C., additional, Cupani, G., additional, Deiries, S., additional, Dekker, H., additional, Delabre, B., additional, Demangeon, O., additional, Di Marcantonio, P., additional, Ehrenreich, D., additional, Fragoso, A., additional, Genolet, L., additional, Genoni, M., additional, Génova Santos, R., additional, Hughes, I., additional, Iwert, O., additional, Knudstrup, J., additional, Landoni, M., additional, Lizon, J. L., additional, Maire, C., additional, Manescau, A., additional, Martins, C. J. A. P., additional, Mégevand, D., additional, Molaro, P., additional, Monteiro, M. J. P. F. G., additional, Monteiro, M. A., additional, Moschetti, M., additional, Mueller, E., additional, Oggioni, L., additional, Oliveira, A., additional, Oshagh, M., additional, Pariani, G., additional, Pasquini, L., additional, Poretti, E., additional, Rasilla, J. L., additional, Redaelli, E., additional, Riva, M., additional, Santana Tschudi, S., additional, Santin, P., additional, Santos, P., additional, Segovia, A., additional, Sosnowska, D., additional, Spanò, P., additional, Tenegi, F., additional, Udry, S., additional, Zanutta, A., additional, and Zerbi, F., additional

Published
2020
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20. First detection of NHD and ND2 in the interstellar medium

Author

Melosso, M., primary, Bizzocchi, L., additional, Sipilä, O., additional, Giuliano, B. M., additional, Dore, L., additional, Tamassia, F., additional, Martin-Drumel, M.-A., additional, Pirali, O., additional, Redaelli, E., additional, and Caselli, P., additional

Published
2020
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21. Revisiting Proxima with ESPRESSO

Author

Suárez Mascareño, A., primary, Faria, J. P., additional, Figueira, P., additional, Lovis, C., additional, Damasso, M., additional, González Hernández, J. I., additional, Rebolo, R., additional, Cristiani, S., additional, Pepe, F., additional, Santos, N. C., additional, Zapatero Osorio, M. R., additional, Adibekyan, V., additional, Hojjatpanah, S., additional, Sozzetti, A., additional, Murgas, F., additional, Abreu, M., additional, Affolter, M., additional, Alibert, Y., additional, Aliverti, M., additional, Allart, R., additional, Allende Prieto, C., additional, Alves, D., additional, Amate, M., additional, Avila, G., additional, Baldini, V., additional, Bandi, T., additional, Barros, S. C. C., additional, Bianco, A., additional, Benz, W., additional, Bouchy, F., additional, Broeng, C., additional, Cabral, A., additional, Calderone, G., additional, Cirami, R., additional, Coelho, J., additional, Conconi, P., additional, Coretti, I., additional, Cumani, C., additional, Cupani, G., additional, D’Odorico, V., additional, Deiries, S., additional, Delabre, B., additional, Di Marcantonio, P., additional, Dumusque, X., additional, Ehrenreich, D., additional, Fragoso, A., additional, Genolet, L., additional, Genoni, M., additional, Génova Santos, R., additional, Hughes, I., additional, Iwert, O., additional, Kerber, F., additional, Knusdstrup, J., additional, Landoni, M., additional, Lavie, B., additional, Lillo-Box, J., additional, Lizon, J., additional, Lo Curto, G., additional, Maire, C., additional, Manescau, A., additional, Martins, C. J. A. P., additional, Mégevand, D., additional, Mehner, A., additional, Micela, G., additional, Modigliani, A., additional, Molaro, P., additional, Monteiro, M. A., additional, Monteiro, M. J. P. F. G., additional, Moschetti, M., additional, Mueller, E., additional, Nunes, N. J., additional, Oggioni, L., additional, Oliveira, A., additional, Pallé, E., additional, Pariani, G., additional, Pasquini, L., additional, Poretti, E., additional, Rasilla, J. L., additional, Redaelli, E., additional, Riva, M., additional, Santana Tschudi, S., additional, Santin, P., additional, Santos, P., additional, Segovia, A., additional, Sosnowska, D., additional, Sousa, S., additional, Spanò, P., additional, Tenegi, F., additional, Udry, S., additional, Zanutta, A., additional, and Zerbi, F., additional

Published
2020
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27. Unraveling one of the densest planets known to date

Author

Toledo-Padrón, B., Lovis, C., Suárez Mascareño, A., Barros, S. C. C., González Hernández, J. I., Sozzetti, A., Bouchy, F., Zapatero Osorio, M. R., Rebolo, R., Cristiani, S., Pepe, F. A., Santos, N. C., Sousa, S. G., Tabernero, H. M., Lillo-Box, J., Bossini, D., Adibekyan, V., Allart, R., Damasso, M., D’Odorico, V., Figueira, P., Lavie, B., Lo Curto, G., Mehner, A., Micela, G., Modigliani, A., Nunes, N. J., Pallé, E., Abreu, M., Affolter, M., Alibert, Y., Aliverti, M., Allende Prieto, C., Alves, D., Amate, M., Avila, G., Baldini, V., Bandy, T., Benatti, S., Benz, W., Bianco, A., Broeg, C., Cabral, A., Calderone, G., Cirami, R., Coelho, J., Conconi, P., Coretti, I., Cumani, C., Cupani, G., Deiries, S., Dekker, H., Delabre, B., Demangeon, O., Di Marcantonio, P., Ehrenreich, D., Fragoso, A., Genolet, L., Genoni, M., Génova Santos, R., Hughes, I., Iwert, O., Knudstrup, J., Landoni, M., Lizon, J. L., Maire, C., Manescau, A., Martins, C. J. A. P., Mégevand, D., Molaro, P., Monteiro, M. J. P. F. G., Monteiro, M. A., Moschetti, M., Mueller, E., Oggioni, L., Oliveira, A., Oshagh, M., Pariani, G., Pasquini, L., Poretti, E., Rasilla, J. L., Redaelli, E., Riva, M., Santana Tschudi, S., Santin, P., Santos, P., Segovia, A., Sosnowska, D., Spanò, P., Tenegi, F., Udry, S., Zanutta, A., and Zerbi, F.

Subjects
530 Physics, 520 Astronomy, 500 Science, 620 Engineering
Abstract

We characterized the transiting planetary system orbiting the G2V star K2-38 using the new-generation echelle spectrograph ESPRESSO. We carried out a photometric analysis of the available K2 photometric light curve of this star to measure the radius of its two known planets. Using 43 ESPRESSO high-precision radial velocity measurements taken over the course of 8 months along with the 14 previously published HIRES RV measurements, we modeled the orbits of the two planets through a MCMC analysis, significantly improving their mass measurements. Using ESPRESSO spectra, we derived the stellar parameters, Teff=5731±66, logg=4.38±0.11~dex, and [Fe/H]=0.26±0.05~dex, and thus the mass and radius of K2-38, M⋆=1.03 +0.04−0.02~M⊕ and R⋆=1.06 +0.09−0.06~R⊕. We determine new values for the planetary properties of both planets. We characterize K2-38b as a super-Earth with RP=1.54±0.14~R⊕ and Mp=7.3+1.1−1.0~M⊕, and K2-38c as a sub-Neptune with RP=2.29±0.26~R⊕ and Mp=8.3+1.3−1.3~M⊕. We derived a mean density of ρp=11.0+4.1−2.8~g cm−3 for K2-38b and ρp=3.8+1.8−1.1~g~cm−3 for K2-38c, confirming K2-38b as one of the densest planets known to date. The best description for the composition of K2-38b comes from an iron-rich Mercury-like model, while K2-38c is better described by a rocky model with a H2 envelope. The maximum collision stripping boundary shows how giant impacts could be the cause for the high density of K2-38b. The irradiation received by each planet places them on opposite sides of the radius valley. We find evidence of a long-period signal in the radial velocity time-series whose origin could be linked to a 0.25-3~MJ planet or stellar activity.

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29. ESPRESSO at VLT

Author

Pepe, F., Cristiani, S., Rebolo, R., Santos, N. C., Dekker, H., Cabral, A., Di Marcantonio, P., Figueira, P., Lo Curto, G., Lovis, C., Mayor, M., Mégevand, D., Molaro, P., Riva, M., Zapatero Osorio, M. R., Amate, M., Manescau, A., Pasquini, L., Zerbi, F. M., Adibekyan, V., Abreu, M., Affolter, M., Alibert, Y., Aliverti, M., Allart, R., Allende Prieto, C., Álvarez, D., Alves, D., Avila, G., Baldini, V., Bandy, T., Barros, S. C. C., Benz, W., Bianco, A., Borsa, F., Bourrier, V., Bouchy, F., Broeg, C., Calderone, G., Cirami, R., Coelho, J., Conconi, P., Coretti, I., Cumani, C., Cupani, G., D’Odorico, V., Damasso, M., Deiries, S., Delabre, B., Demangeon, O. D. S., Dumusque, X., Ehrenreich, D., Faria, J. P., Fragoso, A., Genolet, L., Genoni, M., Génova Santos, R., González Hernández, J. I., Hughes, I., Iwert, O., Kerber, F., Knudstrup, J., Landoni, M., Lavie, B., Lillo-Box, J., Lizon, J.-L., Maire, C., Martins, C. J. A. P., Mehner, A., Micela, G., Modigliani, A., Monteiro, M. A., Monteiro, M. J. P. F. G., Moschetti, M., Murphy, M. T., Nunes, N., Oggioni, L., Oliveira, A., Oshagh, M., Pallé, E., Pariani, G., Poretti, E., Rasilla, J. L., Rebordão, J., Redaelli, E. M., Santana Tschudi, S., Santin, P., Santos, P., Ségransan, D., Schmidt, T. M., Segovia, A., Sosnowska, D., Sozzetti, A., Sousa, S. G., Spanò, P., Suárez Mascareño, A., Tabernero, H., Tenegi, F., Udry, S., and Zanutta, A.

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30. First detection of NHD and ND2 in the interstellar medium

Author

Paola Caselli, Olivier Pirali, Filippo Tamassia, Barbara M. Giuliano, Marie-Aline Martin-Drumel, Mattia Melosso, Luca Bizzocchi, Olli Sipilä, Luca Dore, Elena Redaelli, Melosso M., Bizzocchi L., Sipila O., Giuliano B.M., Dore L., Tamassia F., Martin-Drumel M.-A., Pirali O., Redaelli E., and Caselli P.

Subjects
Physics, Astrochemistry, Amidogen, Line: identification, Continuum (design consultancy), Astronomy and Astrophysics, Context (language use), ISM: molecule, Astrophysics, 010402 general chemistry, 01 natural sciences, ISM: abundance, 0104 chemical sciences, Interstellar medium, chemistry.chemical_compound, Deuterium, chemistry, Space and Planetary Science, 0103 physical sciences, Protostar, Isotopologue, Submillimeter: ISM, 010303 astronomy & astrophysics
Abstract

Context. Deuterium fractionation processes in the interstellar medium (ISM) have been shown to be highly efficient in the family of nitrogen hydrides. To date, observations have been limited to ammonia (NH2D, NHD2, ND3) and imidogen radical (ND) isotopologues. Aims. We want to explore the high-frequency windows offered by the Herschel Space Observatory to search for deuterated forms of the amidogen radical NH2 and to compare the observations against the predictions of our comprehensive gas-grain chemical model. Methods. Making use of the new molecular spectroscopy data recently obtained at high frequencies for NHD and ND2, we searched for both isotopologues in the spectral survey toward the Class 0 protostar IRAS 16293-2422, a source in which NH3, NH, and their deuterated variants have previously been detected. We used the observations carried out with HIFI (Heterodyne Instrument for the Far-Infrared) in the framework of the key program “Chemical Herschel surveys of star forming regions” (CHESS). Results. We report the first detection of interstellar NHD and ND2. Both species are observed in absorption against the continuum of the protostar. From the analysis of their hyperfine structure, accurate excitation temperature and column density values are determined. The latter were combined with the column density of the parent species NH2 to derive the deuterium fractionation in amidogen. We find a high deuteration level of amidogen radical in IRAS 16293-2422, with a deuterium enhancement about one order of magnitude higher than that predicted by earlier astrochemical models. Such a high enhancement can only be reproduced by a gas-grain chemical model if the pre-stellar phase preceding the formation of the protostellar system has a long duration: on the order of one million years. Conclusions. The amidogen D/H ratio measured in the low-mass protostar IRAS 16293-2422 is comparable to that derived for the related species imidogen and much higher than that observed for ammonia. Additional observations of these species will provide more insights into the mechanism of ammonia formation and deuteration in the ISM. Finally, we indicate the current possibilities to further explore these species at submillimeter wavelengths.

Published
2020
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31. 14N/15N ratio measurements in prestellar cores with N2H+: new evidence of 15N-antifractionation

Author

Jorma Harju, Luca Dore, E. Leonardo, Luca Bizzocchi, Elena Redaelli, Paola Caselli, Ana Chacón-Tanarro, Department of Physics, Redaelli, E., Bizzocchi, L., Caselli, P., Harju, J., Chacón-Tanarro, A., Leonardo, E., and Dore, L.

Subjects
Solar System, STARLESS CORES, 010504 meteorology & atmospheric sciences, NITROGEN ISOTOPIC FRACTIONATION, FOS: Physical sciences, DUST, ISM: molecule, Astrophysics, ISM: clouds, 01 natural sciences, ISM: abundances, GAS TEMPERATURE, SOLAR-SYSTEM, RADIATIVE-TRANSFER, ISM: cloud, 0103 physical sciences, Radiative transfer, 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), 0105 earth and related environmental sciences, Physics, radio lines: ISM, stars: formation, Molecular cloud, L694-2, Astronomy and Astrophysics, Astronomy and Astrophysic, 115 Astronomy, Space science, Astrophysics - Astrophysics of Galaxies, ISM: abundance, ISM: molecules, HYPERFINE EXCITATION, Astrophysics - Solar and Stellar Astrophysics, 13. Climate action, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), MOLECULAR CLOUDS, DEPLETION
Abstract

Context: The $^{15}$N fractionation has been observed to show large variations among astrophysical sources, depending both on the type of target and on the molecular tracer used. These variations cannot be reproduced by the current chemical models. Aims: Until now, the $^{14}$N/$^{15}$N ratio in N$_2$H$^+$ has been accurately measured in only one prestellar source, L1544, where strong levels of fractionation, with depletion in $^{15}$N, are found ($^{14}$N/$^{15}$N$\: \approx 1000$). In this paper we extend the sample to three more bona fide prestellar cores, in order to understand if the antifractionation in N$_2$H$^+$ is a common feature of this kind of sources. Methods: We observed N$_2$H$^+$,N$^{15}$NH$^+$ and $^{15}$NNH$^+$ in L183, L429 and L694-2 with the IRAM 30m telescope. We modeled the emission with a non-local radiative transfer code in order to obtain accurate estimates of the molecular column densities, including the one for the optically thick N$_2$H$^+$. We used the most recent collisional rate coefficients available, and with these we also re-analysed the L1544 spectra previously published. Results: The obtained isotopic ratios are in the range $630-770$ and significantly differ with the value, predicted by the most recent chemical models, of $\approx 440$, close to the protosolar value. Our prestellar core sample shows high level of depletion of $^{15}$N in diazenylium, as previously found in L1544. A revision of the N chemical networks is needed in order to explain these results., Comment: Accepted for publication in A&A

Published
2018
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