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Title: Thermal starless ammonia core surrounded by CCS in the Orion a cloud

Abstract

We imaged two starless molecular cloud cores, TUKH083 and TUKH122, in the Orion A giant molecular cloud in the CCS and NH{sub 3} emission with the Very Large Array. TUKH122 contains one NH{sub 3} core 'TUKH122-n', which is elongated and has a smooth oval boundary. Where observed, the CCS emission surrounds the NH{sub 3} core. This configuration resembles that of the N{sub 2}H{sup +} and CCS distribution in the Taurus starless core L1544, a well-studied example of a dense prestellar core exhibiting infall motions. The linewidth of TUKH122-n is narrow (0.20 km s{sup –1}) in the NH{sub 3} emission line and therefore dominated by thermal motions. The smooth oval shape of the core boundary and narrow linewidth in N{sub 2}H{sup +} seem to imply that TUKH122-n is dynamically relaxed and quiescent. TUKH122-n is similar to L1544 in the kinetic temperature (10 K), linear size (0.03 pc), and virial mass (∼2 M {sub ☉}). Our results strongly suggest that TUKH122-n is on the verge of star formation. TUKH122-n is embedded in the 0.2 pc massive (virial mass ∼30 M {sub ☉}) turbulent parent core, while the L1544 NH{sub 3} core is embedded in the 0.2 pc less-massive (virial mass ∼10 Mmore » {sub ☉}) thermal parent core. TUKH083 shows complicated distribution in NH{sub 3}, but was not detected in CCS. The CCS emission toward TUKH083 appears to be extended, and is resolved out in our interferometric observations.« less

Authors:
; ; ; ;  [1];  [2]; ;  [3];  [4];  [5]
  1. National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan)
  2. Department of Astronomy, The University of Tokyo, Bunkyo-ku, Tokyo 113-0033 (Japan)
  3. Korea Astronomy and Space Science Institute, Daedeokdaero 776, Yuseong, Daejeon 305-348 (Korea, Republic of)
  4. School of Space Research, Kyung Hee University, Seocheon-Dong, Giheung-Gu, Yongin-Si, Gyeonggi-Do 446-701 (Korea, Republic of)
  5. Department of Physics, The University of Tokyo, Bunkyo-ku, Tokyo 113-0033 (Japan)
Publication Date:
OSTI Identifier:
22356445
Resource Type:
Journal Article
Journal Name:
Astrophysical Journal
Additional Journal Information:
Journal Volume: 789; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0004-637X
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; AMMONIA; CONFIGURATION; DISTRIBUTION; EMISSION; MASS; MOLECULES; STARS

Citation Formats

Tatematsu, Ken'ichi, Hirota, Tomoya, Umemoto, Tomofumi, Kandori, Ryo, Mizuno, Norikazu, Ohashi, Satoshi, Choi, Minho, Kang, Miju, Lee, Jeong-Eun, and Yamamoto, Satoshi, E-mail: k.tatematsu@nao.ac.jp, E-mail: tomoya.hirota@nao.ac.jp, E-mail: umemoto.tomofumi@nao.ac.jp, E-mail: r.kandori@nao.ac.jp, E-mail: norikazu.mizuno@nao.ac.jp, E-mail: satoshi.ohashi@nao.ac.jp, E-mail: minho@kasi.re.kr, E-mail: mjkang@kasi.re.kr, E-mail: jeongeun.lee@khu.ac.kr, E-mail: yamamoto@taurus.phys.s.u-tokyo.ac.jp. Thermal starless ammonia core surrounded by CCS in the Orion a cloud. United States: N. p., 2014. Web. doi:10.1088/0004-637X/789/1/83.
Tatematsu, Ken'ichi, Hirota, Tomoya, Umemoto, Tomofumi, Kandori, Ryo, Mizuno, Norikazu, Ohashi, Satoshi, Choi, Minho, Kang, Miju, Lee, Jeong-Eun, & Yamamoto, Satoshi, E-mail: k.tatematsu@nao.ac.jp, E-mail: tomoya.hirota@nao.ac.jp, E-mail: umemoto.tomofumi@nao.ac.jp, E-mail: r.kandori@nao.ac.jp, E-mail: norikazu.mizuno@nao.ac.jp, E-mail: satoshi.ohashi@nao.ac.jp, E-mail: minho@kasi.re.kr, E-mail: mjkang@kasi.re.kr, E-mail: jeongeun.lee@khu.ac.kr, E-mail: yamamoto@taurus.phys.s.u-tokyo.ac.jp. Thermal starless ammonia core surrounded by CCS in the Orion a cloud. United States. doi:10.1088/0004-637X/789/1/83.
Tatematsu, Ken'ichi, Hirota, Tomoya, Umemoto, Tomofumi, Kandori, Ryo, Mizuno, Norikazu, Ohashi, Satoshi, Choi, Minho, Kang, Miju, Lee, Jeong-Eun, and Yamamoto, Satoshi, E-mail: k.tatematsu@nao.ac.jp, E-mail: tomoya.hirota@nao.ac.jp, E-mail: umemoto.tomofumi@nao.ac.jp, E-mail: r.kandori@nao.ac.jp, E-mail: norikazu.mizuno@nao.ac.jp, E-mail: satoshi.ohashi@nao.ac.jp, E-mail: minho@kasi.re.kr, E-mail: mjkang@kasi.re.kr, E-mail: jeongeun.lee@khu.ac.kr, E-mail: yamamoto@taurus.phys.s.u-tokyo.ac.jp. Tue . "Thermal starless ammonia core surrounded by CCS in the Orion a cloud". United States. doi:10.1088/0004-637X/789/1/83.
@article{osti_22356445,
title = {Thermal starless ammonia core surrounded by CCS in the Orion a cloud},
author = {Tatematsu, Ken'ichi and Hirota, Tomoya and Umemoto, Tomofumi and Kandori, Ryo and Mizuno, Norikazu and Ohashi, Satoshi and Choi, Minho and Kang, Miju and Lee, Jeong-Eun and Yamamoto, Satoshi, E-mail: k.tatematsu@nao.ac.jp, E-mail: tomoya.hirota@nao.ac.jp, E-mail: umemoto.tomofumi@nao.ac.jp, E-mail: r.kandori@nao.ac.jp, E-mail: norikazu.mizuno@nao.ac.jp, E-mail: satoshi.ohashi@nao.ac.jp, E-mail: minho@kasi.re.kr, E-mail: mjkang@kasi.re.kr, E-mail: jeongeun.lee@khu.ac.kr, E-mail: yamamoto@taurus.phys.s.u-tokyo.ac.jp},
abstractNote = {We imaged two starless molecular cloud cores, TUKH083 and TUKH122, in the Orion A giant molecular cloud in the CCS and NH{sub 3} emission with the Very Large Array. TUKH122 contains one NH{sub 3} core 'TUKH122-n', which is elongated and has a smooth oval boundary. Where observed, the CCS emission surrounds the NH{sub 3} core. This configuration resembles that of the N{sub 2}H{sup +} and CCS distribution in the Taurus starless core L1544, a well-studied example of a dense prestellar core exhibiting infall motions. The linewidth of TUKH122-n is narrow (0.20 km s{sup –1}) in the NH{sub 3} emission line and therefore dominated by thermal motions. The smooth oval shape of the core boundary and narrow linewidth in N{sub 2}H{sup +} seem to imply that TUKH122-n is dynamically relaxed and quiescent. TUKH122-n is similar to L1544 in the kinetic temperature (10 K), linear size (0.03 pc), and virial mass (∼2 M {sub ☉}). Our results strongly suggest that TUKH122-n is on the verge of star formation. TUKH122-n is embedded in the 0.2 pc massive (virial mass ∼30 M {sub ☉}) turbulent parent core, while the L1544 NH{sub 3} core is embedded in the 0.2 pc less-massive (virial mass ∼10 M {sub ☉}) thermal parent core. TUKH083 shows complicated distribution in NH{sub 3}, but was not detected in CCS. The CCS emission toward TUKH083 appears to be extended, and is resolved out in our interferometric observations.},
doi = {10.1088/0004-637X/789/1/83},
journal = {Astrophysical Journal},
issn = {0004-637X},
number = 1,
volume = 789,
place = {United States},
year = {2014},
month = {7}
}