FAST Observations of Four Comets to Search for the Molecular Line Emissions between 1.0 and 1.5 GHz Frequencies

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Main Authors: Chen, Long-Fei, Tsai, Chao-Wei, Li, Jian-Yang, Yang, Bin, Li, Di, Duan, Yan, Hsia, Chih-Hao, Pan, Zhichen, Qian, Lei, Quan, Donghui, Jiang, Xue-Jian, Li, Xiaohu, Zhao, Ruining, Zuo, Pei
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Published: 2024
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author Chen, Long-Fei
Tsai, Chao-Wei
Li, Jian-Yang
Yang, Bin
Li, Di
Duan, Yan
Hsia, Chih-Hao
Pan, Zhichen
Qian, Lei
Quan, Donghui
Jiang, Xue-Jian
Li, Xiaohu
Zhao, Ruining
Zuo, Pei
author_facet Chen, Long-Fei
Tsai, Chao-Wei
Li, Jian-Yang
Yang, Bin
Li, Di
Duan, Yan
Hsia, Chih-Hao
Pan, Zhichen
Qian, Lei
Quan, Donghui
Jiang, Xue-Jian
Li, Xiaohu
Zhao, Ruining
Zuo, Pei
contents We used the Five-hundred-meter Aperture Spherical radio Telescope (FAST) to search for the molecular emissions in the L-band between 1.0 and 1.5 GHz toward four comets, C/2020 F3 (NEOWISE), C/2020 R4 (ATLAS), C/2021 A1 (Leonard), and 67P/Churyumov-Gerasimenko during or after their perihelion passages. Thousands of molecular transition lines fall in this low-frequency range, many attributed to complex organic or prebiotic molecules. We conducted a blind search for the possible molecular lines in this frequency range in those comets and could not identify clear signals of molecular emissions in the data. Although several molecules have been detected at high frequencies of great than 100 GHz in comets, our results confirm that it is challenging to detect molecular transitions in the L-band frequency ranges. The non-detection of L-band molecular lines in the cometary environment could rule out the possibility of unusually strong lines, which could be caused by the masers or non-LTE effects. Although the line strengths are predicted to be weak, for FAST, using the ultra-wide bandwidth receiver and improving the radio frequency interference environments would enhance the detectability of those molecular transitions at low frequencies in the future.
format Preprint
id arxiv_https___arxiv_org_abs_2409_06227
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle FAST Observations of Four Comets to Search for the Molecular Line Emissions between 1.0 and 1.5 GHz Frequencies
Chen, Long-Fei
Tsai, Chao-Wei
Li, Jian-Yang
Yang, Bin
Li, Di
Duan, Yan
Hsia, Chih-Hao
Pan, Zhichen
Qian, Lei
Quan, Donghui
Jiang, Xue-Jian
Li, Xiaohu
Zhao, Ruining
Zuo, Pei
Earth and Planetary Astrophysics
We used the Five-hundred-meter Aperture Spherical radio Telescope (FAST) to search for the molecular emissions in the L-band between 1.0 and 1.5 GHz toward four comets, C/2020 F3 (NEOWISE), C/2020 R4 (ATLAS), C/2021 A1 (Leonard), and 67P/Churyumov-Gerasimenko during or after their perihelion passages. Thousands of molecular transition lines fall in this low-frequency range, many attributed to complex organic or prebiotic molecules. We conducted a blind search for the possible molecular lines in this frequency range in those comets and could not identify clear signals of molecular emissions in the data. Although several molecules have been detected at high frequencies of great than 100 GHz in comets, our results confirm that it is challenging to detect molecular transitions in the L-band frequency ranges. The non-detection of L-band molecular lines in the cometary environment could rule out the possibility of unusually strong lines, which could be caused by the masers or non-LTE effects. Although the line strengths are predicted to be weak, for FAST, using the ultra-wide bandwidth receiver and improving the radio frequency interference environments would enhance the detectability of those molecular transitions at low frequencies in the future.
title FAST Observations of Four Comets to Search for the Molecular Line Emissions between 1.0 and 1.5 GHz Frequencies
topic Earth and Planetary Astrophysics
url https://arxiv.org/abs/2409.06227