Volume 627, July 2019
|Number of page(s)||12|
|Section||Interstellar and circumstellar matter|
|Published online||17 July 2019|
A particular carbon-chain-producing region: L1489 starless core★
Department of Astronomy, Peking University,
2 School of Astronomy and Space Sciences, University of Science and Technology of China, 96 Jinzhai Road, Hefei 230026, PR China
3 Purple Mountain Observatory and Key Laboratory of Radio Astronomy, Chinese Academy of Sciences, 8 Yuanhua Road, Nanjing 210034, PR China
4 Shanghai Astronomical Observatory, Chinese Academy of Sciences, Shanghai 200030, PR China
5 Center for Astrophysics, GuangZhou University, Guangzhou 510006, PR China
6 Korea Astronomy and Space Science Institute, 776 Daedeokdae-ro, Yuseong-gu, Daejeon 34055, Korea
7 East Asian Observatory, 660 North A’ohoku Place, Hilo, HI 96720, USA
8 Department of Astronomy, Yunnan University, Kunming 650091, PR China
9 National Astronomical Observatories, Chinese Academy of Sciences, 20A Datun Road, Chaoyang District, Beijing 100101, PR China
10 Department of Physics, The Chinese University of Hong Kong, Shatin, NT, Hong Kong
11 Departamento de Astronomía, Universidad de Concepción, Av. Esteban Iturra s/n, Distrito Universitario, 160-C, Chile
Accepted: 9 May 2019
We detected carbon-chain molecules (CCMs) HC2n+1N (n = 1−3) and C3S in Ku band as well as high-energy excitation lines including C4H N = 9–8, J = 17/2–15/2, 19/2–17/2, and CH3CCH J = 5–4, K = 2 in the 3 mm band toward a starless core called the eastern molecular core (EMC) of L1489 IRS. Maps of all the observed lines were also obtained. Comparisons with a number of early starless cores and the warm carbon-chain chemistry (WCCC) source L1527 show that the column densities of C4H and CH3CCH are close to those of L1527, and the CH3CCH column densities of the EMC and L1527 are slightly higher than those of TMC-1. The EMC and L1527 have similar C3S column densities, but they are much lower than those of all the starless cores, with only 6.5 and 10% of the TMC-1 value, respectively. The emissions of the N-bearing species of the EMC and L1527 are at the medium level of the starless cores. These comparisons show that the CCM emissions in the EMC are similar to those of L1527, though L1527 contains a protostar. Although dark and quiescent, the EMC is warmer and at a later evolutionary stage than classical carbon-chain–producing regions in the cold, dark, quiescent early phase. The PACS, SPIRE, and SCUBA maps evidently show that the L1489 IRS seems to be the heating source of the EMC. Although it is located at the margins of the EMC, its bolometric luminosity and bolometric temperature are relatively high. Above all, the EMC is a rather particular carbon-chain-producing region and is quite significant for CCM science.
Key words: ISM: molecules / ISM: abundances / stars: formation / ISM: jets and outflows
A copy of the reduced datacubes (FITS files) is available at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (22.214.171.124) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/627/A162
© ESO 2019
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