FAUST I. The hot corino at the heart of the prototypical Class I protostar L1551 IRS5. (21st July 2020)

• Record Type: Journal Article
• Authors: Bianchi, E; 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; Zhang, Y; Zhao, B; Yamamoto, S;
• Is Part Of: Monthly notices of the Royal Astronomical Society. Volume 498:Number 1(2020)
• Page Start: L87
• Page End: L92
• Publication Date: 2020-07-21
• Subjects: astrochemistry -- stars: formation -- ISM: molecules; Astronomy -- Research -- Periodicals; Periodicals; 520.5
• DOI: 10.1093/mnrasl/slaa130
• Languages: English
• ISSNs: 1745-3933

Abstract

ABSTRACT: 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 ( 13 CH3 OH and CH2 DOH), 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 × 10 8 cm −3 ), and emitting size (∼10 au in radius). All CH3 OH and 13 CH3 OH 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.