Examinando por Autor "Watanabe, Y."

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FAUST I. The hot corino at the heart of the prototypical Class I protostar L1551 IRS5.
(Oxford Academics: Oxford University Press, 2020-07-21) Bianchi, S.; Chandler, C. J.; Ceccarelli, C.; Codella, C.; Sakai, N.; López Sepulcre, A.; Maud, L. T.; Moellenbrock, G.; Svoboda, B.; Watanabe, Y.; Sakai, T.; Ménard, F.; Aikawa, Y.; Alves, F.; Balucani, N.; Bouvier, M.; Caselli, P.; Caux, E.; Charnley, S.; Choudhury, S.; De Simone, M.; Dulieu, F.; Durán, A.; Evans, L.; Favre, C.; Fedele, D.; Feng, S.; Fontani, F.; Francis, L.; Hama, T.; Hanawa, T.; Herbst, E.; Hirota, T.; Imai, M.; Isella, A.; Jiménez Serra, I.; Johnstone, D.; Kahane, C.; Lefloch, B.; Loinard, L.; Maureira, M. J.; Mercimek, S.; Miotello, A.; Mori, S.; Nakatani, R.; Nomura, H.; Oba, Y.; Ohashi, S.; Okoda, Y.; Ospina Zamudio, J.; Oya, Y.; Pineda, J.; Podio, L.; Rimola, A.; Segura Cox, D.; Shirley, Y.; Taquet, V.; Testi, L.; Vastel, C.; Viti, S.; Watanabe, N.; Witzel, A.; Xue, C.; Zhao, B.; Zhang, Y.; Yamamoto, S.; European Research Council (ERC); Japan Society for the Promotion of Science (KAKENHI); Agencia Estatal de Investigación (AEI); Universidad Nacional Autónoma de México (UNAM); Agence Nationale de la Recherche (ANR); Balucani, N. [0000-0001-5121-5683]; De Oliveira Alves, F. [0000-0002-7945-064X]; Hama, T. [0000-0002-4991-4044]; Ohashi, S. [0000-0002-9661-7958]; Johnstone, D. [0000-0002-6773-459X]; Watanabe, Y. [0000-0002-9668-3592]; Ceccarelli, C. [0000-0001-9664-6292]; Pineda, J. [0000-0002-3972-1978]; Fedele, D. [0000-0001-6156-0034]; Mercimek, S. [0000-0002-0742-7934]; Xue, C. [0000-0003-2760-2119]; Sakai, N. [0000-0002-3297-4497]; Unidad de Excelencia Científica María de Maeztu Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, MDM-2017-0737
The study of hot corinos in solar-like protostars has been so far mostly limited to the Class 0 phase, hampering our understanding of their origin and evolution. In addition, recent evidence suggests that planet formation starts already during Class I phase, which therefore represents a crucial step in the future planetary system chemical composition. Hence, the study of hot corinos in Class I protostars has become of paramount importance. Here, we report the discovery of a hot corino towards the prototypical Class I protostar L1551 IRS5, obtained within the ALMA (Atacama Large Millimeter/submillimeter Array) Large Program FAUST (Fifty AU STudy of the chemistry in the disc/envelope system of solar-like protostars). We detected several lines from methanol and its isotopologues (13CH3OH and CH2DOH), methyl formate, and ethanol. Lines are bright towards the north component of the IRS5 binary system, and a possible second hot corino may be associated with the south component. The methanol lines' non-LTE analysis constrains the gas temperature (∼100 K), density (≥1.5 × 108 cm−3), and emitting size (∼10 au in radius). All CH3OH and 13CH3OH lines are optically thick, preventing a reliable measure of the deuteration. The methyl formate and ethanol relative abundances are compatible with those measured in Class 0 hot corinos. Thus, based on this work, little chemical evolution from Class 0 to I hot corinos occurs.
Acceso Abierto
FAUST. II. Discovery of a Secondary Outflow in IRAS 15398−3359: Variability in Outflow Direction during the Earliest Stage of Star Formation?
(The Institute of Physics (IOP), 2021-03-22) Okoda, Y.; Oya, Y.; Francis, L.; Johnstone, D.; Inutsuka, S. I.; Ceccarelli, C.; Codella, C.; Chandler, C. J.; Sakai, N.; Aikawa, Y.; Alves, F.; Balucani, N.; Bianchi, E.; Bouvier, M.; Caselli, P.; Caux, E.; Charnley, S.; Choudhury, S.; De Simone, M.; Dulieu, F.; Durán, A.; Evans, L.; Favre, C.; Fedele, D.; Feng, S.; Fontani, F.; Hama, T.; Hanawa, T.; Herbst, E.; Hirota, T.; Imai, M.; Isella, A.; Jiménez Serra, I.; Kahane, C.; Lefloch, B.; Loinard, L.; López Sepulcre, A.; Maud, L. T.; Maureira, M. J.; Ménard, F.; Mercimek, S.; Miotello, A.; Moellenbrock, G.; Mori, S.; Murillo, Nadia M.; Nakatani, R.; Nomura, H.; Oba, Y.; O´Donoghue, R.; Ohashi, S.; Ospina Zamudio, J.; Pineda, J. E.; Podio, L.; Rimola, A.; Sakai, T.; Segura Cox, D.; Shirley, Y.; Svoboda, B.; Taquet, V.; Testi, L.; Vastel, C.; Viti, S.; Watanabe, N.; Watanabe, Y.; Witzel, A.; Xue, C.; Zhang, Y.; Zhao, B.; Yamamoto, S.; European Research Council (ERC); Agencia Estatal de Investigación (AEI); Japan Society for the Promotion of Science (JSPS); Okoda, Y. [0000-0003-3655-5270]; Oya, Y. [0000-0002-0197-8751]; Francis, L. [0000-0001-8822-6327]; Johnstone, D. [0000-0002-6773-459X]; Inutsuka, S. I. [0000-0003-4366-6518]; Ceccarelli, C. [0000-0001-9664-6292]; Codella, C. [0000-0003-1514-3074]; Chandler, C. [0000-0002-7570-5596]; Sakai, N. [0000-0002-3297-4497]; Aikawa, Y. [0000-0003-3283-6884]; Alves, F. [0000-0002-7945-064X]; Balucani, N. [0000-0001-5121-5683]; Bianchi, E. [0000-0001-9249-7082]; Bouvier, M. [0000-0003-0167-0746]; Caselli, P. [0000-0003-1481-7911]; De Simone, M. [0000-0001-5659-0140]; Feng, S. [0000-0002-4707-8409]; Fontani, F. [0000-0003-0348-3418]; Hama, T. [0000-0002-4991-4044]; Hanawa, T. [0000-0002-7538-581X]; Herbst, E. [0000-0002-4649-2536]; Hirota, T. [0000-0003-1659-095X]; Imai, M. [0000-0002-5342-6262]; Isella, A. [0000-0001-8061-2207]; Jiménez Serra, I. [0000-0003-4493-8714]; Kahane, C. [0000-0003-1691-4686]; Loinard, L. [0000-0002-5635-3345]; López Sepulcre, A. [0000-0002-6729-3640]; Maud, L. T. [0000-0002-7675-3565]; Maureira, M. J. [0000-0002-7026-8163]; Menard, F. [0000-0002-1637-7393]; Miotello, A. [0000-0002-7997-2528]; Moellenbrock, G. [0000-0002-3296-8134]; Oba, Y. [0000-0002-6852-3604]; Ohashi, S. [0000-0002-9661-7958]; Pineda, J. E. [0000-0002-3972-1978]; Rimola, A. [0000-0002-9637-4554]; Sakai, T. [0000-0003-4521-7492]; Segura Cox, D. [0000-0003-3172-6763]; Svoboda, B. [0000-0002-8502-6431]; Taquet, V. [0000-0003-0407-7489]
We have observed the very low-mass Class 0 protostar IRAS 15398−3359 at scales ranging from 50 to 1800 au, as part of the Atacama Large Millimeter/Submillimeter Array Large Program FAUST. We uncover a linear feature, visible in H2CO, SO, and C18O line emission, which extends from the source in a direction almost perpendicular to the known active outflow. Molecular line emission from H2CO, SO, SiO, and CH3OH further reveals an arc-like structure connected to the outer end of the linear feature and separated from the protostar, IRAS 15398−3359, by 1200 au. The arc-like structure is blueshifted with respect to the systemic velocity. A velocity gradient of 1.2 km s−1 over 1200 au along the linear feature seen in the H2CO emission connects the protostar and the arc-like structure kinematically. SO, SiO, and CH3OH are known to trace shocks, and we interpret the arc-like structure as a relic shock region produced by an outflow previously launched by IRAS 15398−3359. The velocity gradient along the linear structure can be explained as relic outflow motion. The origins of the newly observed arc-like structure and extended linear feature are discussed in relation to turbulent motions within the protostellar core and episodic accretion events during the earliest stage of protostellar evolution.