中国物理B ›› 2025, Vol. 34 ›› Issue (6): 69701-069701.doi: 10.1088/1674-1056/adbedc

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JCMT observations of CO, SO2, and a U-line in circumstellar envelopes of four O-rich AGB stars

Yanan Feng(冯亚楠)1,2, Xiaohu Li(李小虎)1,3,4,†, Sheng-Li Qin(秦胜利)5, Tom J. Millar6, Ryszard Szczerba1,3, Zhenzhen Miao(苗珍珍)1,3, and Juan Tuo(庹娟)1,3   

  1. 1 Xinjiang Astronomical Observatory, Chinese Academy of Sciences, Xinjiang Uygur Autonomous Region, Urumqi 830011, China;
    2 University of Chinese Academy of Sciences, Beijing 100049, China;
    3 Xinjiang Key Laboratory of Radio Astrophysics, Xinjiang Uygur Autonomous Region, Urumqi 830011, China;
    4 State Key Laboratory of Radio Astronomy and Technology, Chinese Academy of Sciences, Beijing 100101, China;
    5 Department of Astronomy, Yunnan University, Kunming 650091, China;
    6 Astrophysics Research Centre, School of Mathematics and Physics, Queen's University Belfast, Belfast, BT7 1NN, UK
  • 收稿日期:2024-11-16 修回日期:2025-02-20 接受日期:2025-03-11 出版日期:2025-05-16 发布日期:2025-06-12
  • 通讯作者: Xiaohu Li E-mail:xiaohu.li@xao.ac.cn
  • 基金资助:
    Science Foundation of Xinjiang Uygur Autonomous Region, China (Grant No. 2024D01E37) and the National Natural Science Foundation of China (Grant No. 12473025).TJM’s Research at QUB supported by grant number ST/T000198/1 from the STFC, Zhenzhen Miao thanks the sponsored by Natural Science Foundation of Xinjiang Uygur Autonomous Region, China (Grant No. 2022D01B221), and Sheng-Li Qin thanks the Xinjiang Tianchi Talent Project (2019). The James Clerk Maxwell Telescope is operated by the East Asian Observatory on behalf of the National Astronomical Observatory of Japan, Academia Sinica Institute of Astronomy and Astrophysics, the Korea Astronomy and Space Science Institute, the National Astronomical Research Institute of Thailand, Center for Astronomical Mega-Science as well as the National Key Research and Development Program of China (Grant No. 2017YFA0402700). Additional funding support is provided by the Science and Technology Facilities Council of the United Kingdom and participating universities and organizations in the United Kingdom and Canada. This work was supported by the JCMT M22BP013 project.

JCMT observations of CO, SO2, and a U-line in circumstellar envelopes of four O-rich AGB stars

Yanan Feng(冯亚楠)1,2, Xiaohu Li(李小虎)1,3,4,†, Sheng-Li Qin(秦胜利)5, Tom J. Millar6, Ryszard Szczerba1,3, Zhenzhen Miao(苗珍珍)1,3, and Juan Tuo(庹娟)1,3   

  1. 1 Xinjiang Astronomical Observatory, Chinese Academy of Sciences, Xinjiang Uygur Autonomous Region, Urumqi 830011, China;
    2 University of Chinese Academy of Sciences, Beijing 100049, China;
    3 Xinjiang Key Laboratory of Radio Astrophysics, Xinjiang Uygur Autonomous Region, Urumqi 830011, China;
    4 State Key Laboratory of Radio Astronomy and Technology, Chinese Academy of Sciences, Beijing 100101, China;
    5 Department of Astronomy, Yunnan University, Kunming 650091, China;
    6 Astrophysics Research Centre, School of Mathematics and Physics, Queen's University Belfast, Belfast, BT7 1NN, UK
  • Received:2024-11-16 Revised:2025-02-20 Accepted:2025-03-11 Online:2025-05-16 Published:2025-06-12
  • Contact: Xiaohu Li E-mail:xiaohu.li@xao.ac.cn
  • Supported by:
    Science Foundation of Xinjiang Uygur Autonomous Region, China (Grant No. 2024D01E37) and the National Natural Science Foundation of China (Grant No. 12473025).TJM’s Research at QUB supported by grant number ST/T000198/1 from the STFC, Zhenzhen Miao thanks the sponsored by Natural Science Foundation of Xinjiang Uygur Autonomous Region, China (Grant No. 2022D01B221), and Sheng-Li Qin thanks the Xinjiang Tianchi Talent Project (2019). The James Clerk Maxwell Telescope is operated by the East Asian Observatory on behalf of the National Astronomical Observatory of Japan, Academia Sinica Institute of Astronomy and Astrophysics, the Korea Astronomy and Space Science Institute, the National Astronomical Research Institute of Thailand, Center for Astronomical Mega-Science as well as the National Key Research and Development Program of China (Grant No. 2017YFA0402700). Additional funding support is provided by the Science and Technology Facilities Council of the United Kingdom and participating universities and organizations in the United Kingdom and Canada. This work was supported by the JCMT M22BP013 project.

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摘要： The circumstellar envelopes (CSE) of asymptotic giant branch (AGB) stars are abundant in molecular emissions, offering valuable insights into the physical and chemical conditions of these evolving stars. In this paper, we report observations of two molecules (CO and SO$_2$) toward four O-rich AGB stars using the James Clerk Maxwell Telescope (JCMT). We detected an unusual SO$_2$ spectral feature comprising both broad and narrow components in IK Tau and AP Lyn. The broad line profiles may originate from thermal molecular emission, while the narrow profiles could come from other species (or masers) or astrophysical phenomena occurring within the CSEs of the AGB stars, such as episodic mass loss, bipolar outflows, or emissions associated with the complex physical processes near the central star. The narrow lines of SO$_2$ may also arise from vibrationally excited emissions. Additionally, we observed the same U-line in both TX Cam and IK Tau, which may originate from the molecule N$^{17}$O. We analyzed the identified molecular lines using rotational diagrams to determine their excitation temperatures, column densities, and fractional abundances. This information aids in the constructing of reliable astrochemical models for a more detailed examination of the target stars. The narrow component of the SO$_2$ line suggests unusual astrophysical phenomena, making IK Tau and AP Lyn particularly intriguing for further investigation to fully understand the physical processes at play in these sources.

关键词: asymptotic giant branch, circumstellar envelopes, SO$_2$

Abstract: The circumstellar envelopes (CSE) of asymptotic giant branch (AGB) stars are abundant in molecular emissions, offering valuable insights into the physical and chemical conditions of these evolving stars. In this paper, we report observations of two molecules (CO and SO$_2$) toward four O-rich AGB stars using the James Clerk Maxwell Telescope (JCMT). We detected an unusual SO$_2$ spectral feature comprising both broad and narrow components in IK Tau and AP Lyn. The broad line profiles may originate from thermal molecular emission, while the narrow profiles could come from other species (or masers) or astrophysical phenomena occurring within the CSEs of the AGB stars, such as episodic mass loss, bipolar outflows, or emissions associated with the complex physical processes near the central star. The narrow lines of SO$_2$ may also arise from vibrationally excited emissions. Additionally, we observed the same U-line in both TX Cam and IK Tau, which may originate from the molecule N$^{17}$O. We analyzed the identified molecular lines using rotational diagrams to determine their excitation temperatures, column densities, and fractional abundances. This information aids in the constructing of reliable astrochemical models for a more detailed examination of the target stars. The narrow component of the SO$_2$ line suggests unusual astrophysical phenomena, making IK Tau and AP Lyn particularly intriguing for further investigation to fully understand the physical processes at play in these sources.

Key words: asymptotic giant branch, circumstellar envelopes, SO$_2$

中图分类号:  (Circumstellar shells, clouds, and expanding envelopes; circumstellar masers)

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