The Origin of Universality in the Inner Edges of Planetary Systems
The characteristic orbital period of the innermost objects within the galactic census of planetary and satellite systems appears to be nearly universal, with P on the order of a few days. This paper presents a theoretical framework that provides a simple explanation for this phenomenon. By consideri...
| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
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IOP Publishing
2023-01-01
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| Series: | The Astrophysical Journal Letters |
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| Online Access: | https://doi.org/10.3847/2041-8213/acdb5d |
| _version_ | 1797699505803493376 |
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| author | Konstantin Batygin Fred C. Adams Juliette Becker |
| author_facet | Konstantin Batygin Fred C. Adams Juliette Becker |
| author_sort | Konstantin Batygin |
| collection | DOAJ |
| description | The characteristic orbital period of the innermost objects within the galactic census of planetary and satellite systems appears to be nearly universal, with P on the order of a few days. This paper presents a theoretical framework that provides a simple explanation for this phenomenon. By considering the interplay between disk accretion, magnetic field generation by convective dynamos, and Kelvin–Helmholtz contraction, we derive an expression for the magnetospheric truncation radius in astrophysical disks and find that the corresponding orbital frequency is independent of the mass of the host body. Our analysis demonstrates that this characteristic frequency corresponds to a period of P ∼ 3 days although intrinsic variations in system parameters are expected to introduce a factor of a ∼2–3 spread in this result. Standard theory of orbital migration further suggests that planets should stabilize at an orbital period that exceeds disk truncation by a small margin. Cumulatively, our findings predict that the periods of close-in bodies should span P ∼ 2–12 days—a range that is consistent with observations. |
| first_indexed | 2024-03-12T04:09:47Z |
| format | Article |
| id | doaj.art-5f2965c61eae48e79c014f3783eeffc0 |
| institution | Directory Open Access Journal |
| issn | 2041-8205 |
| language | English |
| last_indexed | 2024-03-12T04:09:47Z |
| publishDate | 2023-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | The Astrophysical Journal Letters |
| spelling | doaj.art-5f2965c61eae48e79c014f3783eeffc02023-09-03T11:06:45ZengIOP PublishingThe Astrophysical Journal Letters2041-82052023-01-019511L1910.3847/2041-8213/acdb5dThe Origin of Universality in the Inner Edges of Planetary SystemsKonstantin Batygin0https://orcid.org/0000-0002-7094-7908Fred C. Adams1https://orcid.org/0000-0002-8167-1767Juliette Becker2https://orcid.org/0000-0002-7733-4522Division of Geological and Planetary Sciences, California Institute of Technology , Pasadena, CA 91125, USAPhysics Department, University of Michigan , Ann Arbor, MI 48109, USA; Astronomy Department, University of Michigan , Ann Arbor, MI 48109, USADivision of Geological and Planetary Sciences, California Institute of Technology , Pasadena, CA 91125, USAThe characteristic orbital period of the innermost objects within the galactic census of planetary and satellite systems appears to be nearly universal, with P on the order of a few days. This paper presents a theoretical framework that provides a simple explanation for this phenomenon. By considering the interplay between disk accretion, magnetic field generation by convective dynamos, and Kelvin–Helmholtz contraction, we derive an expression for the magnetospheric truncation radius in astrophysical disks and find that the corresponding orbital frequency is independent of the mass of the host body. Our analysis demonstrates that this characteristic frequency corresponds to a period of P ∼ 3 days although intrinsic variations in system parameters are expected to introduce a factor of a ∼2–3 spread in this result. Standard theory of orbital migration further suggests that planets should stabilize at an orbital period that exceeds disk truncation by a small margin. Cumulatively, our findings predict that the periods of close-in bodies should span P ∼ 2–12 days—a range that is consistent with observations.https://doi.org/10.3847/2041-8213/acdb5dPlanet formationExoplanet formationCircumstellar disksMagnetohydrodynamics |
| spellingShingle | Konstantin Batygin Fred C. Adams Juliette Becker The Origin of Universality in the Inner Edges of Planetary Systems The Astrophysical Journal Letters Planet formation Exoplanet formation Circumstellar disks Magnetohydrodynamics |
| title | The Origin of Universality in the Inner Edges of Planetary Systems |
| title_full | The Origin of Universality in the Inner Edges of Planetary Systems |
| title_fullStr | The Origin of Universality in the Inner Edges of Planetary Systems |
| title_full_unstemmed | The Origin of Universality in the Inner Edges of Planetary Systems |
| title_short | The Origin of Universality in the Inner Edges of Planetary Systems |
| title_sort | origin of universality in the inner edges of planetary systems |
| topic | Planet formation Exoplanet formation Circumstellar disks Magnetohydrodynamics |
| url | https://doi.org/10.3847/2041-8213/acdb5d |
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