Chemical and Physical Characterization of the Isolated Protostellar Source CB68: FAUST IV
Chemical and Physical Characterization of the Isolated Protostellar Source CB68: FAUST IV
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DOI：
10.3847/1538-4357/ac77e7
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发表时间：
2022-06
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通讯作者：
M. Imai;Y. Oya;B. Svoboda;H. Liu;B. Lefloch;S. Viti;Yichen Zhang;C. Ceccarelli;C. Codella;C. Chandler;N. Sakai;Y. Aikawa;F. Alves;N. Balucani;E. Bianchi;M. Bouvier;G. Busquet;P. Caselli;E. Caux;S. Charnley;S. Choudhury;N. Cuello;M. D. Simone;F. Dulieu;Aurora Durán;L. Evans;C. Favre;D. Fedele;S. Feng;F. Fontani;L. Francis;T. Hama;T. Hanawa;E. Herbst;S. Hirano;T. Hirota;A. Isella;I. Jímenez-Serra;D. Johnstone;C. Kahane;R. Le Gal;L. Loinard;A. López-Sepulcre;L. Maud;M. Maureira;F. Ménard;S. Mercimek;A. Miotello;G. Moellenbrock;S. Mori;N. Murillo;Riouhei Nakatani;H. Nomura;Y. Oba;R. O’Donoghue;S. Ohashi;Y. Okoda;J. Ospina-Zamudio;J. Pineda;L. Podio;A. Rimola;T. Sakai;D. Segura-Cox;Y. Shirley;V. Taquet;L. Testi;C. Vastel;N. Watanabe;Yoshimasa Watanabe;A. Witzel;C. Xue;B. Zhao;S. Yamamoto
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作者：
M. Imai;Y. Oya;B. Svoboda;H. Liu;B. Lefloch;S. Viti;Yichen Zhang;C. Ceccarelli;C. Codella;C. Chandler;N. Sakai;Y. Aikawa;F. Alves;N. Balucani;E. Bianchi;M. Bouvier;G. Busquet;P. Caselli;E. Caux;S. Charnley;S. Choudhury;N. Cuello;M. D. Simone;F. Dulieu;Aurora Durán;L. Evans;C. Favre;D. Fedele;S. Feng;F. Fontani;L. Francis;T. Hama;T. Hanawa;E. Herbst;S. Hirano;T. Hirota;A. Isella;I. Jímenez-Serra;D. Johnstone;C. Kahane;R. Le Gal;L. Loinard;A. López-Sepulcre;L. Maud;M. Maureira;F. Ménard;S. Mercimek;A. Miotello;G. Moellenbrock;S. Mori;N. Murillo;Riouhei Nakatani;H. Nomura;Y. Oba;R. O’Donoghue;S. Ohashi;Y. Okoda;J. Ospina-Zamudio;J. Pineda;L. Podio;A. Rimola;T. Sakai;D. Segura-Cox;Y. Shirley;V. Taquet;L. Testi;C. Vastel;N. Watanabe;Yoshimasa Watanabe;A. Witzel;C. Xue;B. Zhao;S. Yamamoto
到目前为止，低质量原恒星源的化学多样性已得到认可，并且环境效应被认为是其成因。在此背景下，对不受附近天体影响的孤立原恒星源的观测尤为重要。在此，我们基于作为大型项目FAUST一部分所进行的、空间分辨率约为70天文单位的1.3毫米阿塔卡马大型毫米波/亚毫米波阵列观测，报告了博克球状体CB 68中低质量0级原恒星源IRAS 16544 - 1604的化学和物理结构。在原恒星方向探测到了三种星际饱和复杂有机分子（iCOMs），即甲醇（CH₃OH）、甲酸甲酯（HCOOCH₃）和二甲醚（CH₃OCH₃）。甲醇的转动温度和发射区域大小分别推导出为131±11开尔文和约10天文单位。在紧邻原恒星处探测到iCOMs表明CB 68包含一个热晕（hot corino）。C¹⁸O、CH₃OH和OCS谱线的运动学结构可以用一个吸积 - 旋转包层模型来解释，原恒星质量和离心屏障半径分别估计为0.08 - 0.30倍太阳质量和小于30天文单位。离心屏障的小半径似乎与iCOMs的小发射区域有关。此外，我们探测到了与原恒星相关的环丙烯基（c - C₃H₂）和乙炔基（CCH）的发射谱线，揭示了在1000天文单位尺度上的暖碳链化学。因此我们发现CB 68的化学结构可以用一种混合化学来描述。我们还将分子丰度与其他热晕源中的分子丰度以及已报道的化学模型进行了比较讨论。
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.