Detection of OH Maser Emission in the 71 yr Periodic Comet 12P/Pons-Brooks Using the 40 m Thai National Radio Telescope
Abstract Although the optical cometary database is extensive, the radio database is limited. The 18 cm OH maser observations of comets allow us to determine (i) the production rate of OH ( Q OH ) and (ii) the water expansion velocity, for each comet. To reveal the physical properties of the periodic comet 12P/Pons-Brooks, we conducted the OH maser observations of the comet using the 40 m Thai National Radio Telescope on 2024 March 22, 27, and 29, before the perihelion passage on 2024 April 21. We successfully detected 1665 and 1667 MHz OH maser emissions from the comet. The average OH production rates of 12P/Pons-Brooks were determined as 4.28 ± 0.30 × 10 29 s −1 , 5.21 ± 0.42 × 10 29 s −1 , and 3.36 ± 0.43 × 10 29 s −1 for March 22, 27, and 29, respectively. Combining our results with previous estimates, we find that the OH production rate of 12P/Pons-Brooks shows some fluctuations on timescales of a few days, but gradually increases on longer timescales as the comet approaches the last perihelion. The water expansion velocities of the comet were determined to be 1.55 ± 0.14, 1.55 ± 0.35, and 2.02 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msubsup> <mml:mrow/> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>0.45</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>+</mml:mo> <mml:mn>0.47</mml:mn> </mml:mrow> </mml:msubsup> </mml:math> km s −1 for the observations on March 22, 27, and 29, respectively. The reason why the errors are different is because the signal-to-noise ratio is different for each OH maser emission. All expansion velocities are consistent with the individual results of the heuristic law within errors.
Authors
- B. Pimpanuwat (ORCID: https://orcid.org/0000-0001-8782-0754)
- Nattapong Duangrit (ORCID: https://orcid.org/0000-0003-2617-8627)
- Kamorn Bandudej
- E D Barr (ORCID: https://orcid.org/0000-0001-8715-9628)
- P. de Vicente (ORCID: https://orcid.org/0000-0002-5902-5005)
- Songklod Punyawarin
- B. Hutawarakorn Kramer (ORCID: https://orcid.org/0000-0001-8168-5141)
- Nawamin Intrarat
- Jason Wu (ORCID: https://orcid.org/0000-0003-3536-4368)
- Boonrucksar Soonthornthum (ORCID: https://orcid.org/0000-0001-5511-7183)
- Dan Singwong
- Apichat Leckngam
- Chen Yuan (ORCID: https://orcid.org/0000-0001-8560-5487)
- S. Poshyachinda
- N Prasert
- W. Rujopakarn (ORCID: https://orcid.org/0000-0002-0303-499X)
- G. Wieching (ORCID: https://orcid.org/0000-0002-2758-1840)
- T. Winchen (ORCID: https://orcid.org/0000-0002-5756-4304)
- Hideyuki Kobayashi (ORCID: https://orcid.org/0000-0001-8066-1631)
- Phrudth Jaroenjittichai (ORCID: https://orcid.org/0000-0002-9676-5424)
- Nattawit Chanwedchasart
- Nobuyuki Sakai (ORCID: https://orcid.org/0000-0002-5814-0554)
- Koichiro Sugiyama (ORCID: https://orcid.org/0000-0002-6033-5000)
- Lalida Tantiparimongkol
- Spiro George Sarris
- Niclas Esser
- Chayanin Larkaew
- Attapon Bunwong
- Wijitra Potakum
- Kitipoom Kanjana
- Teep Chairin
- Chalunthon Nuchur
- Haseng Sani
- Pathit Chatuphot
- Prachayapan Jiraya
- Saharat Sathipjan
- Adirake Eakwan
- Settasak Naewchan
- Pichate Pha-Kham
- Siritida Duangbuppha
- Thodsawat Chaichana
- Panupan Doomcome
- Anya Poonnawatt
- Warakorn Noisapung
- Pathorn Sathapornvajana
- Naphat Yawilerng
- Thita Dilokthanakul
- Kritsada Angkaew
- Nattawut Chaiwongwan
- Jittimat Khanchaiyapoom
- Natthaphong Kruekoch
- Nonwarit Borvornsareepirom
- Sothaya Prathumsub
- Natee PongTeerarat
- Nonnadda Silamai
- Nutdanai Hantankul
- Thanadon Paksin
- Ornjira Krataithong
Institutions
- Yebes Observatory (ES)
- Max Planck Institute for Radio Astronomy (DE)
- National Astronomical Observatory of Japan (JP)
- National Astronomical Research Institute of Thailand (TH)
Publication Details
- Journal
- The Planetary Science Journal
- Published
- 2025-11-01
- DOI
- https://doi.org/10.3847/psj/ae0e19
- Primary Topic
- Astro and Planetary Science
- Type
- article
- Field-Weighted Citation Impact
- 0.00