ALMA Observations of Vibrationally Excited HC{sub 3}N Lines Toward Orion KL

Journal Article · Wed Mar 01 04:00:00 EST 2017 · Astrophysical Journal

DOI:https://doi.org/10.3847/1538-4357/AA5C81· OSTI ID:22869280

Peng, Yaping; Qin, Sheng-Li; Zhang, Li; Rong, Jia-Lei ^[1]; Schilke, Peter; Sánchez-Monge, Álvaro; Möller, Thomas ^[2]; Wu, Yuefang ^[3]; Liu, Tie ^[4]; Li, Di; Luo, Gan ^[5]; Liu, Sheng-Yuan ^[6]; Feng, Siyi ^[7]; Liu, Ying ^[8]

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1. Department of Astronomy, Yunnan University, and Key Laboratory of Astroparticle Physics of Yunnan Province, Kunming, 650091 (China)
2. I. Physikalisches Institut, Universität zu Köln, Zülpicher Str. 77, D-50937 Köln (Germany)
3. Department of Astronomy, Peking University, Beijing, 100871 (China)
4. Korea Astronomy and Space Science Institute 776, Daedeokdaero, Yuseong-gu, Daejeon 305-348 (Korea, Republic of)
5. National Astronomical Observatories, Chinese Academy of Science, Chaoyang District, Datun Road 20A, Beijing (China)
6. Institute of Astronomy and Astrophysics, Academia Sinica, Taipei, Taiwan (China)
7. Max-Planck-Institut für Extraterrestrische Physik, Giessenbachstrasse 1, D-85748, Garching (Germany)
8. Department of Physics and Hebei Advanced Thin Film Laboratory, Hebei Normal University, Shijiazhuang 050024 (China)

We present high spatial resolution ALMA observations of vibrational transitions of HC{sub 3}N toward Orion KL in the 214–247 GHz frequency band. 41 transitions of HC{sub 3}N in 7 vibrationally excited states, and 23 transitions of {sup 13}C isotopologues of HC{sub 3}N in 2 vibrational states are detected. The line images show that vibrationally excited HC{sub 3}N lines originate mainly from the hot core of Orion and IRc7. The images of HC{sub 3}N vibrationally excited lines show that the line emission peaks associated with the hot core move from south to northeast as E{sub u} increases. Based on multiple transitions of each vibrationally excited state, we performed local thermodynamic equilibrium calculations in the XCLASS suite toward the hot core and IRc7 positions. Generally, transitions in highly excited states have higher rotational temperatures and lower column densities. The rotational temperatures and column densities of the hot core range from 93 to 321 K, and from 1.0×10{sup 14} to 4.9×10{sup 16} cm{sup −2}, respectively. Lower rotational temperatures ranging from 88 to 186 K and column densities from 1.0×10{sup 14} to 3.2×10{sup 16} cm{sup −2} are obtained toward IRc7. The facts that the hot core emission peaks of vibrationally excited HC{sub 3}N lines move from south to northeast with increasing E{sub u}, and that higher-energy HC{sub 3}N lines have higher rotational temperatures and lower column densities, appear to support that the hot core is externally heated. The emission peaks are moving along the major axis of the SiO outflow, which may indicate that higher-energy HC{sub 3}N transitions are excited by interaction between pre-existing dense medium and shocks generated by SiO outflows.

• OSTI ID: 22869280
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 1 Vol. 837; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
ABUNDANCE
AUGMENTATION
CARBON 13
DENSITY
EMISSION
INTERACTIONS
LTE
MOLECULES
NITRILES
SPATIAL RESOLUTION
STARS
THERMODYNAMICS
VIBRATIONAL STATES