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ヒグチ アリカ
Higuchi Arika
樋口 有理可 所属 京都産業大学 理学部 宇宙物理・気象学科 職種 准教授 |
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| 言語種別 | 英語 |
| 発行・発表の年月 | 2019/11/11 |
| 形態種別 | 研究論文 |
| 査読 | 査読あり |
| 標題 | Hyperbolic Orbits in the Solar System: Interstellar Origin or Perturbed Oort Cloud Comets? |
| 執筆形態 | その他 |
| 掲載誌名 | Monthly Notices of the Royal Astronomical Society |
| 出版社・発行元 | Oxford University Press (OUP) |
| 担当区分 | 筆頭著者,責任著者 |
| 著者・共著者 | Arika Higuchi,Eiichiro Kokubo |
| 概要 | <title>Abstract</title>
We study the dynamical properties of objects in hyperbolic orbits passing through the inner Solar system in the context of two different potential sources: interstellar space and the Oort cloud. We analytically derive the probability distributions of eccentricity, e, and perihelion distance, q, for each source and estimate the numbers of objects produced per unit of time as a function of these quantities. By comparing the numbers from the two sources, we assess which origin is more likely for a hyperbolic object having a given eccentricity and perihelion distance. We find that the likelihood that a given hyperbolic object is of interstellar origin increases with decreasing eccentricity and perihelion. Conversely, the likelihood that a hyperbolic object has been scattered from the Oort cloud by a passing star increases with decreasing eccentricity and increasing perihelion. By carefully considering their orbital elements, we conclude that both 1I/2017 U1 ’Oumuamua (e ≃ 1.2 and q ≃ 0.26 au) and 2I/2019 Q4 Borisov (e ≃ 3.3 and q ≃ 2 au) are most likely of interstellar origin, not scattered from the Oort cloud. However, we also find that Oort cloud objects can be scattered into hyperbolic orbits like those of the two known examples, by sub-stellar and even sub-Jovian mass perturbers. This highlights the need for better characterization of the low mass end of the free-floating brown dwarf and planet population. |
| DOI | 10.1093/mnras/stz3153 |
| ISSN | 0035-8711/1365-2966 |
| PermalinkURL | http://academic.oup.com/mnras/advance-article-pdf/doi/10.1093/mnras/stz3153/30648311/stz3153.pdf |