TY - JOUR
T1 - A chemical view of protostellar-disk formation in L1527
AU - Sakai, Nami
AU - Oya, Yoko
AU - Sakai, Takeshi
AU - Watanabe, Yoshimasa
AU - Hirota, Tomoya
AU - Ceccarelli, Cecilia
AU - Kahane, Claudine
AU - Lopez-Sepulcre, Ana
AU - Lefloch, Bertrand
AU - Vastel, Charlotte
AU - Bottinelli, Sandrine
AU - Caux, Emmanuel
AU - Coutens, Audrey
AU - Aikawa, Yuri
AU - Takakuwa, Shigehisa
AU - Ohashi, Nagayoshi
AU - Yen, Hsi Wei
AU - Yamamoto, Satoshi
PY - 2014/8/20
Y1 - 2014/8/20
N2 - Subarcsecond images of the rotational line emissions of CCH, CS, H 2CO, and CH3OH have been obtained toward the low-mass protostar IRAS 04368+2557 in L1527 as one of the early science projects of the Atacama Large Millimeter/submillimeter Array. The intensity distributions of CCH and CS show a double-peaked structure along the edge-on envelope with a dip toward the protostar position, whereas those of H2CO and CH 3OH are centrally peaked. By analyzing the position-velocity diagrams along the envelope, CCH and CS are found to reside mainly in the envelope, where the gas is infalling with conservation of its angular momentum. They are almost absent inward of the centrifugal barrier (a half of the centrifugal radius). Although H2CO exists in the infalling rotating envelope, it also resides in the disk component inside the centrifugal barrier to some extent. On the other hand, CH3OH seems to exist around the centrifugal barrier and in the disk component. Hence, the drastic chemical change occurs at the centrifugal barrier. A discontinuous infalling motion as well as the gas-grain interaction would be responsible for the chemical change. This result will put an important constraint on initial chemical compositions for chemical evolution of protostellar disks.
AB - Subarcsecond images of the rotational line emissions of CCH, CS, H 2CO, and CH3OH have been obtained toward the low-mass protostar IRAS 04368+2557 in L1527 as one of the early science projects of the Atacama Large Millimeter/submillimeter Array. The intensity distributions of CCH and CS show a double-peaked structure along the edge-on envelope with a dip toward the protostar position, whereas those of H2CO and CH 3OH are centrally peaked. By analyzing the position-velocity diagrams along the envelope, CCH and CS are found to reside mainly in the envelope, where the gas is infalling with conservation of its angular momentum. They are almost absent inward of the centrifugal barrier (a half of the centrifugal radius). Although H2CO exists in the infalling rotating envelope, it also resides in the disk component inside the centrifugal barrier to some extent. On the other hand, CH3OH seems to exist around the centrifugal barrier and in the disk component. Hence, the drastic chemical change occurs at the centrifugal barrier. A discontinuous infalling motion as well as the gas-grain interaction would be responsible for the chemical change. This result will put an important constraint on initial chemical compositions for chemical evolution of protostellar disks.
KW - ISM: abundances
KW - ISM: individual objects (L1527)
KW - ISM: molecules
KW - stars: formation
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U2 - 10.1088/2041-8205/791/2/L38
DO - 10.1088/2041-8205/791/2/L38
M3 - Article
AN - SCOPUS:84905738945
VL - 791
JO - Astrophysical Journal Letters
JF - Astrophysical Journal Letters
SN - 2041-8205
IS - 2
M1 - L38
ER -