TY - JOUR
T1 - Change in the chemical composition of infalling gas forming a disk around a protostar
AU - Sakai, Nami
AU - Sakai, Takeshi
AU - Hirota, Tomoya
AU - Watanabe, Yoshimasa
AU - Ceccarelli, Cecilia
AU - Kahane, Claudine
AU - Bottinelli, Sandrine
AU - Caux, Emmanuel
AU - Demyk, Karine
AU - Vastel, Charlotte
AU - Coutens, Audrey
AU - Taquet, Vianney
AU - Ohashi, Nagayoshi
AU - Takakuwa, Shigehisa
AU - Yen, Hsi Wei
AU - Aikawa, Yuri
AU - Yamamoto, Satoshi
PY - 2014
Y1 - 2014
N2 - IRAS 04368+2557 is a solar-type (low-mass) protostar embedded in a protostellar core (L1527) in the Taurus molecular cloud, which is only 140 parsecs away from Earth, making it the closest large star-forming region. The protostellar envelope has a flattened shape with a diameter of a thousand astronomical units (1 au is the distance from Earth to the Sun), and is infalling and rotating. It also has a protostellar disk with a radius of 90 au (ref. 6), from which a planetary system is expected to form. The interstellar gas, mainly consisting of hydrogen molecules, undergoes a change in density of about three orders of magnitude as it collapses from the envelope into the disk, while being heated from 10 kelvin to over 100 kelvin in the mid-plane, but it has hitherto not been possible to explore changes in chemical composition associated with this collapse. Here we report that the unsaturated hydrocarbon molecule cyclic-C 3 H 2 resides in the infalling rotating envelope, whereas sulphur monoxide (SO) is enhanced in the transition zone at the radius of the centrifugal barrier (100 ± 20 au), which is the radius at which the kinetic energy of the infalling gas is converted to rotational energy. Such a drastic change in chemistry at the centrifugal barrier was not anticipated, but is probably caused by the discontinuous infalling motion at the centrifugal barrier and local heating processes there.
AB - IRAS 04368+2557 is a solar-type (low-mass) protostar embedded in a protostellar core (L1527) in the Taurus molecular cloud, which is only 140 parsecs away from Earth, making it the closest large star-forming region. The protostellar envelope has a flattened shape with a diameter of a thousand astronomical units (1 au is the distance from Earth to the Sun), and is infalling and rotating. It also has a protostellar disk with a radius of 90 au (ref. 6), from which a planetary system is expected to form. The interstellar gas, mainly consisting of hydrogen molecules, undergoes a change in density of about three orders of magnitude as it collapses from the envelope into the disk, while being heated from 10 kelvin to over 100 kelvin in the mid-plane, but it has hitherto not been possible to explore changes in chemical composition associated with this collapse. Here we report that the unsaturated hydrocarbon molecule cyclic-C 3 H 2 resides in the infalling rotating envelope, whereas sulphur monoxide (SO) is enhanced in the transition zone at the radius of the centrifugal barrier (100 ± 20 au), which is the radius at which the kinetic energy of the infalling gas is converted to rotational energy. Such a drastic change in chemistry at the centrifugal barrier was not anticipated, but is probably caused by the discontinuous infalling motion at the centrifugal barrier and local heating processes there.
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U2 - 10.1038/nature13000
DO - 10.1038/nature13000
M3 - Article
AN - SCOPUS:84895927236
VL - 507
SP - 78
EP - 80
JO - Nature
JF - Nature
SN - 0028-0836
IS - 7490
ER -