Dynamics of the comet 157P/Tritton and its fragments
Abstract
This work examines the dynamics of the comet 157P/Tritton and its fragment 157P-B, observed in 2022. Light curves of the comet in four recent apparitions, especially in 2017, show irregular changes in the comet's brightness. At the same time, the sign of the non-gravitational parameter A 2 changed, which may also indicate an unstable state of the comet's nucleus. Analysis of "O–C" in 2021–2023 suggests that there were two fragments, and each of the two fragments was observed for approximately two weeks with interval between them of 10 days. The time of fragment separation from the main body was estimated as a result of varying the moment of separation and determining at this moment the velocity components of the fragment. It was assumed that the minimum value of the root mean square error corresponds to the separation time. The time of separation of the first fragment from the main body is estimated quite confidently, with an error of tens of days. The most probable date is June 6, 2020, this is approximately three months after the approach to Jupiter and two years before passing through perihelion. The time of separation of the second fragment from the main body is estimated less confidently; it could have occurred over an interval of about 800 days, so two options were considered: separation at the beginning of this interval June 6, 2020, and the end of July 1, 2022. The possibility of separating the second fragment from the first one is also considered. The estimated time of this event is closer to the beginning of the given interval, which indicates that both fragments could have formed almost simultaneously. As of June 6, 2020 the separation velocity of the first fragment was |∆v 1 | = (5.02 ± 0.07) m/s. The angle between the velocity vectors of the main body and the velocity change, θ 1 , is equal to 133.2 ◦ . As of June 6, 2020 the separation velocity of the second fragment was |∆v 2 | = (0.87 ± 0.21) m/s and θ 2 = 96.2 ◦ . If the separation of the second fragment from the main body occurred shortly before the start of its observations July 1, 2022 , then |∆v 2 | = (5.68 ± 0.88) m/s and θ 2 = 164.0 ◦ . The velocity of separation of the second fragment from the first one is not estimated due to a large error. The circumstances of the fragmentation of the comet 157P/Tritton suggest that the most likely cause of fragmentation could be a collision with some small body. This paper is based on a talk presented at VIII Bredikhin conference.
- Publication:
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INASAN Science Reports
- Pub Date:
- December 2023
- DOI:
- 10.51194/INASAN.2023.8.6.007
- Bibcode:
- 2023INASR...8..292K
- Keywords:
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- split comets;
- fragment of comet;
- comet 157P/Tritton