Browsing by Author "Codella, C."
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Item FAUST - V. Hot methanol in the [BHB2007] 11 protobinary system; hot corino versus shock origin(EDP Sciences, 2022) Vastel, C.; Alves, F.; Ceccarelli, C.; Bouvier, M.; Jiménez-Serra, I.; Sakai, T.; Caselli, P.; Evans, L.; Fontani, F.; Gal, R. Le; Chandler, C.J.; Svoboda, B.; Maud, L.; Codella, C.; Sakai, N.; Lόpez-Sepulcre, A.; Moellenbrock, G.; Aikawa, Y.; Balucani, N.; Bianchi, E.; Busquet, G.; Caux, E.; Charnley, S.; Cuello, N.; Simone, M. De; Dulieu, F.; Durân, A.; Fedele, D.; Feng, S.; Francis, L.; Hama, T.; Hanawa, T.; Herbst, E.; Hirota, T.; Imai, M.; Isella, A.; Johnstone, D.; Lefloch, B.; Loinard, L.; Maureira, M.; Murillo, N.M.; Mercimek, S.; Mori, S.; Menard, F.; Miotello, A.; Nakatani, R.; Nomura, H.; Oba, Y.; Ohashi, S.; Okoda, Y.; Ospina-Zamudio, J.; Oya, Y.; Pineda, J.E.; Podio, L.; Rimola, A.; Cox, D. Segura; Shirley, Y.; Testi, L.; Viti, S.; Watanabe, N.; Watanabe, Y.; Witzel, A.; Xue, C.; Zhang, Y.; Zhao, B.; Yamamoto, S.Aims.Methanol is a ubiquitous species commonly found in the molecular interstellar medium. It is also a crucial seed species for the build-up of chemical complexity in star forming regions. Thus, understanding how its abundance evolves during the star formation process and whether it enriches the emerging planetary system is of paramount importance.Methods. We used new data from the ALMA Large Program FAUST (Fifty AU STudy of the chemistry in the disc/envelope system of solar protostars) to study the methanol line emission towards the [BHB2007] 11 protobinary system (sources A and B), where a complex structure of filaments connecting the two sources with a larger circumbinary disc has previously been detected.Results. Twelve methanol lines have been detected with upper energies in the [45–537] K range along with one 13CH3OH transition and one methyl formate (CH3OCHO) line blended with one of the methanol transitions. The methanol emission is compact (FWHM ~ 0.5″) and encompasses both protostars, which are separated by only 0.2″ (28 au). In addition, the overall methanol line emission presents three velocity components, which are not spatially resolved by our observations. Nonetheless, a detailed analysis of the spatial origin of these three components suggests that they are associated with three different spatial regions, with two of them close to 11B and the third one associated with 11A. A radiative transfer analysis of the methanol lines gives a kinetic temperature of [100–140] K, an H2 volume density of 106–107 cm−3 and column density of a few 1018 cm−2 in all three components with a source size of ~0.15″. Thus, this hot and dense gas is highly enriched in methanol with an abundance as high as 10−5. Using previous continuum data, we show that dust opacity can potentially completely absorb the methanol line emission from the two binary objects.Conclusions. Although we cannot firmly exclude other possibilities, we suggest that the detected hot methanol is resulting from the shocked gas from the incoming filaments streaming towards [BHB2007] 11A and B, respectively. Higher spatial resolution observations are necessary to confirm this hypothesis.Item FAUST - XIII. Dusty cavity and molecular shock driven by IRS7B in the Corona Australis cluster(EDP Sciences, 2024) Sabatini, G.; Podio, L.; Codella, C.; Watanabe, Y.; Simone, M. De; Bianchi, E.; Ceccarelli, C.; Chandler, C. J.; Sakai, N.; Svoboda, B.; Testi, L.; Aikawa, Y.; Balucani, N.; Bouvier, M.; Caselli, P.; Caux, E.; Chahine, L.; Charnley, S.; Cuello, N.; Dulieu, F.; Evans, L.; Fedele, D.; Feng, S.; Fontani, F.; Hama, T.; Hanawa, T.; Herbst, E.; Hirota, T.; Isella, A.; Jímenez-Serra, I.; Johnstone, D.; Lefloch, B.; Gal, R. Le; Loinard, L.; Liu, H. B.; López-Sepulcre, A.; Maud, L. T.; Maureira, M. J.; Menard, F.; Miotello, A.; Moellenbrock, G.; Nomura, H.; Oba, Y.; Ohashi, S.; Okoda, Y.; Oya, Y.; Pineda, J.; Rimola, A.; Sakai, T.; Segura-Cox, D.; Shirley, Y.; Vastel, C.; Viti, S.; Watanabe, N.; Zhang, Y.; Zhang, Z. E.; Yamamoto, S.Context.The origin of the chemical diversity observed around low-mass protostars probably resides in the earliest history of these systems.Aims. We aim to investigate the impact of protostellar feedback on the chemistry and grain growth in the circumstellar medium of multiple stellar systems. Methods. In the context of the ALMA Large Program FAUST, we present high-resolution (50 au) observations of CH3OH, H2CO, and SiO and continuum emission at 1.3 mm and 3 mm towards the Corona Australis star cluster.Results. Methanol emission reveals an arc-like structure at ∼1800 au from the protostellar system IRS7B along the direction perpendicular to the major axis of the disc. The arc is located at the edge of two elongated continuum structures that define a cone emerging from IRS7B. The region inside the cone is probed by H2CO, while the eastern wall of the arc shows bright emission in SiO, a typical shock tracer. Taking into account the association with a previously detected radio jet imaged with JVLA at 6 cm, the molecular arc reveals for the first time a bow shock driven by IRS7B and a two-sided dust cavity opened by the mass-loss process. For each cavity wall, we derive an average H 2 column density of ∼7 × 1021 cm−2, a mass of ∼9 × 10−3 M⊙, and a lower limit on the dust spectral index of 1.4.Conclusions. These observations provide the first evidence of a shock and a conical dust cavity opened by the jet driven by IRS7B, with important implications for the chemical enrichment and grain growth in the envelope of Solar System analogues.