Chemical and Physical Characterization of the Isolated Protostellar Source CB68: FAUST IV

Muneaki Imai , Yoko Oya , Brian Svoboda , Hauyu Baobab Liu (1) , Bertrand Lefloch (2) , Serena Viti , Yichen Zhang , Cecilia Ceccarelli (2) , Claudio Codella (2) , Claire Chandler , Nami Sakai (3) , Yuri Aikawa (4) , Felipe Alves (5) , Nadia Balucani (6) , Eleonora Bianchi (2) , Mathilde Bouvier (2) , Gemma Busquet (2) , Paola Caselli (7) , Emmanuel Caux (8, 9) , Steven Charnley , Spandan Choudhury , Nicolas Cuello , Marta De Simone , Francois Dulieu (10) , Aurora Durán , Lucy Evans , Cécile Favre (2) , Davide Fedele , Siyi Feng , Francesco Fontani , Logan Francis , Tetsuya Hama , Tomoyuki Hanawa , Eric Herbst , Shingo Hirano , Tomoya Hirota , Andrea Isella , Izaskun Jímenez-Serra , Doug Johnstone , Claudine Kahane (2) , Romane Le Gal (2) , Laurent Loinard , Ana López-Sepulcre , Luke Maud , María José Maureira , Francois Menard (2) , Seyma Mercimek , Anna Miotello , George Moellenbrock , Shoji Mori , Nadia Murillo , Riouhei Nakatani , Hideko Nomura , Yasuhiro Oba , Ross O’donoghue , Satoshi Ohashi , Yuki Okoda , Juan Ospina-Zamudio (2) , Jaime Pineda , Linda Podio , Albert Rimola , Takeshi Sakai , Dominique Segura-Cox , Yancy Shirley , Vianney Taquet , Leonardo Testi , Charlotte Vastel , Naoki Watanabe , Yoshimasa Watanabe , Arezu Witzel (2) , Ci Xue , Bo Zhao , Satoshi Yamamoto

1 ASIAA - Academia Sinica Institute of Astronomy and Astrophysics
2 IPAG - Institut de Planétologie et d'Astrophysique de Grenoble
3 RIKEN - RIKEN - Institute of Physical and Chemical Research [Japon]
4 Department of Astronomy [Tokyo]
5 MPE - Max Planck Institute for Extraterrestrial Physics
6 UNIPG - Università degli Studi di Perugia = University of Perugia
7 MPE - Max-Planck-Institut für Extraterrestrische Physik
8 CNES - Centre National d'Études Spatiales [Toulouse]
9 IRAP - Institut de recherche en astrophysique et planétologie
10 LERMA - LERMA Cergy

Abstract The chemical diversity of low-mass protostellar sources has so far been recognized, and environmental effects are invoked as its origin. In this context, observations of isolated protostellar sources without the influence of nearby objects are of particular importance. Here, we report the chemical and physical structures of the low-mass Class 0 protostellar source IRAS 16544−1604 in the Bok globule CB 68, based on 1.3 mm Atacama Large Millimeter/submillimeter Array observations at a spatial resolution of ∼70 au that were conducted as part of the large program FAUST. Three interstellar saturated complex organic molecules (iCOMs), CH3OH, HCOOCH3, and CH3OCH3, are detected toward the protostar. The rotation temperature and the emitting region size for CH3OH are derived to be 131 ± 11 K and ∼10 au, respectively. The detection of iCOMs in close proximity to the protostar indicates that CB 68 harbors a hot corino. The kinematic structure of the C18O, CH3OH, and OCS lines is explained by an infalling–rotating envelope model, and the protostellar mass and the radius of the centrifugal barrier are estimated to be 0.08–0.30 M ⊙ and <30 au, respectively. The small radius of the centrifugal barrier seems to be related to the small emitting region of iCOMs. In addition, we detect emission lines of c-C3H2 and CCH associated with the protostar, revealing a warm carbon-chain chemistry on a 1000 au scale. We therefore find that the chemical structure of CB 68 is described by a hybrid chemistry. The molecular abundances are discussed in comparison with those in other hot corino sources and reported chemical models.

Domaines: Astrophysique stellaire et solaire [astro-ph.SR]

Muneaki Imai, Yoko Oya, Brian Svoboda, Hauyu Baobab Liu, Bertrand Lefloch, et al.. Chemical and Physical Characterization of the Isolated Protostellar Source CB68: FAUST IV. The Astrophysical Journal, 2022, 934 (1), pp.70. ⟨10.3847/1538-4357/ac77e7⟩. ⟨hal-03797309⟩