Discovery and dynamics of a Sedna-like object with a perihelion of 66 au

Trans-Neptunian objects (TNOs) with large perihelion distances (q > 60 au) and semi-major axes (a > 200 au) provide insights into the early evolution of the Solar System and the existence of a hypothetical distant planet. These objects are challenging to observe, and thus their detections are still rare, yet they play a crucial role in constraining models of Solar System formation. Here we report the discovery of a Sedna-like TNO, 2023 KQ14, nicknamed ‘Ammonite’, with q = 66 au, a = 252 au and inclination i = 11°. The orbit of Ammonite does not align with those of the other Sedna-like objects and fills the previously unexplained ‘q-gap’ in the observed distribution of distant Solar System objects. Simulations demonstrate that Ammonite is dynamically stable over 4.5 Gyr. Our analysis suggests that Ammonite and the other Sedna-like objects may have shared a primordial orbital clustering around 4.2 Ga. Furthermore, the stable orbit of Ammonite favours larger orbits (~500 au) rather than closer ones for a large hypothetical planet in present-day trans-Neptunian space. The discovery of 2023 KQ14, a Sedna-like object with a perihelion of 66 au, fills a gap in the known population. Its orbit does not align with other Sedna-like objects, shedding light on the diversity and dynamical history of the outer Solar System.

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Publication Details

Journal
Nature Astronomy
Published
2025-07-14
DOI
https://doi.org/10.1038/s41550-025-02595-7
Citations
4
Primary Topic
Astro and Planetary Science
Type
article
Field-Weighted Citation Impact
4.62

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article

Discovery and dynamics of a Sedna-like object with a perihelion of 66 au

Ji‐Lin Zhou, Fumi Yoshida, Zhong-Yi Lin, Brett Gladman et al.
4 citations
Nature Astronomy
Astro and Planetary Science
4.62
article

Discovery and dynamics of a Sedna-like object with a perihelion of 66 au

Ji‐Lin Zhou, Fumi Yoshida, Zhong-Yi Lin, Brett Gladman, Hui Zhang, Mike Alexandersen, Michele T. Bannister, Samantha Lawler, Lowell Peltier, Ying-Tung Chen, Surhud More, Myungjin Kim, Haibin Zhao, Tsuyoshi Terai, Keiji Ohtsuki, Patryk Sofia Lykawka, Chan-Kao Chang, Wesley C. Fraser, M. J. Lehner, Shiang‐Yu Wang, J. J. Kavelaars, Youngmin JeongAhn, Marco A. Muñoz-Gutiérrez, Rosemary E. Pike, Seitaro Urakawa, Hong-Kyu Moon, Takashi Itô, Yukun Huang, A. Paula Granados Contreras, Jian Li, Young‐Jun Choi, Jianghui Ji, Edward Ashton
article en
4 citations

Abstract

Trans-Neptunian objects (TNOs) with large perihelion distances (q > 60 au) and semi-major axes (a > 200 au) provide insights into the early evolution of the Solar System and the existence of a hypothetical distant planet. These objects are challenging to observe, and thus their detections are still rare, yet they play a crucial role in constraining models of Solar System formation. Here we report the discovery of a Sedna-like TNO, 2023 KQ14, nicknamed ‘Ammonite’, with q = 66 au, a = 252 au and inclination i = 11°. The orbit of Ammonite does not align with those of the other Sedna-like objects and fills the previously unexplained ‘q-gap’ in the observed distribution of distant Solar System objects. Simulations demonstrate that Ammonite is dynamically stable over 4.5 Gyr. Our analysis suggests that Ammonite and the other Sedna-like objects may have shared a primordial orbital clustering around 4.2 Ga. Furthermore, the stable orbit of Ammonite favours larger orbits (~500 au) rather than closer ones for a large hypothetical planet in present-day trans-Neptunian space. The discovery of 2023 KQ14, a Sedna-like object with a perihelion of 66 au, fills a gap in the known population. Its orbit does not align with other Sedna-like objects, shedding light on the diversity and dynamical history of the outer Solar System.

Nature AstronomyVol. 9(9)
Herzberg Institute of Astrophysics (CA), Institute of Astronomy and Astrophysics, Academia Sinica (TW), University of British Columbia (CA), University of Canterbury (NZ), University of Occupational and Environmental Health Japan (JP), University of Regina (CA), University of Atacama (CL), University of Victoria (CA), National Central University (TW), Shanghai Astronomical Observatory (CN), Korea Astronomy and Space Science Institute (KR), Japan Spaceguard Association (JP), Purple Mountain Observatory (CN), Kavli Institute for the Physics and Mathematics of the Universe (JP), Center for Astrophysics Harvard & Smithsonian (US), Campion College (CA), National Astronomical Observatory of Japan (JP), Inter-University Centre for Astronomy and Astrophysics (IN), Kobe University (JP), University of Pennsylvania (US), Chiba Institute of Technology (JP), Nanjing University (CN), Kindai University (JP)
National Natural Science Foundation of China, Ministry of Science and Technology, Taiwan, Centre National de la Recherche Scientifique, National Astronomical Observatory of Japan, National Science and Technology Council, Japan Society for the Promotion of Science
Openalex Percentile: Top 5%
Astro and Planetary Science
4.62
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