The Fraction of Polar-aligned Circumbinary Disks
Circumbinary gas disks that are misaligned to the binary orbital plane evolve toward either a coplanar or a polar-aligned configuration with respect to the binary host. The preferred alignment depends on the dynamics of the disk: whether it undergoes librating or circulating nodal precession, with l...
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| Language: | English |
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IOP Publishing
2025-01-01
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| Series: | The Astronomical Journal |
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| Online Access: | https://doi.org/10.3847/1538-3881/adde5d |
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| author | Ted M. Johnson Rebecca G. Martin Stephen Lepp Stephen H. Lubow |
| author_facet | Ted M. Johnson Rebecca G. Martin Stephen Lepp Stephen H. Lubow |
| author_sort | Ted M. Johnson |
| collection | DOAJ |
| description | Circumbinary gas disks that are misaligned to the binary orbital plane evolve toward either a coplanar or a polar-aligned configuration with respect to the binary host. The preferred alignment depends on the dynamics of the disk: whether it undergoes librating or circulating nodal precession, with librating disks evolving to polar inclinations and circulating disks evolving to coplanar. We quantify the fraction of binary star systems whose disks are expected to have polar orbits f _polar , extending previous work to include disks with nonzero mass. Our results suggest that, for low mass disks, the polar fraction is highly sensitive to the distribution of binary eccentricity, with a higher fraction expected for higher binary eccentricities, f _polar ∼ e _b . However, for massive disks, the fraction is independent of the binary eccentricity and f _polar ≈ 0.37. The value of f _polar is always reduced in a population with a greater preference for low initial mutual inclination. We also explore the consequences of the finite lifetime and nonzero radial extent of a real disk, both of which affect a disk’s ability to complete its evolution to a stationary configuration. Our findings can be used to make predictions given populations with well-understood distributions of binary eccentricity, initial mutual inclination, and disk angular momentum. |
| format | Article |
| id | doaj-art-47c746d464bf45db9bcf05299020e4ea |
| institution | Kabale University |
| issn | 1538-3881 |
| language | English |
| publishDate | 2025-01-01 |
| publisher | IOP Publishing |
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| series | The Astronomical Journal |
| spelling | doaj-art-47c746d464bf45db9bcf05299020e4ea2025-08-20T03:33:31ZengIOP PublishingThe Astronomical Journal1538-38812025-01-0117027710.3847/1538-3881/adde5dThe Fraction of Polar-aligned Circumbinary DisksTed M. Johnson0https://orcid.org/0000-0002-1570-2203Rebecca G. Martin1https://orcid.org/0000-0003-2401-7168Stephen Lepp2https://orcid.org/0000-0003-2270-1310Stephen H. Lubow3https://orcid.org/0000-0002-4636-7348Nevada Center for Astrophysics, University of Nevada , Las Vegas, 4505 South Maryland Parkway, Las Vegas, NV 89154, USA ; ted.johnson@unlv.edu; Department of Physics and Astronomy, University of Nevada , Las Vegas, 4505 South Maryland Parkway, Las Vegas, NV 89154, USANevada Center for Astrophysics, University of Nevada , Las Vegas, 4505 South Maryland Parkway, Las Vegas, NV 89154, USA ; ted.johnson@unlv.edu; Department of Physics and Astronomy, University of Nevada , Las Vegas, 4505 South Maryland Parkway, Las Vegas, NV 89154, USANevada Center for Astrophysics, University of Nevada , Las Vegas, 4505 South Maryland Parkway, Las Vegas, NV 89154, USA ; ted.johnson@unlv.edu; Department of Physics and Astronomy, University of Nevada , Las Vegas, 4505 South Maryland Parkway, Las Vegas, NV 89154, USASpace Telescope Science Institute , 3700 San Martin Drive, Baltimore, MD 21218, USACircumbinary gas disks that are misaligned to the binary orbital plane evolve toward either a coplanar or a polar-aligned configuration with respect to the binary host. The preferred alignment depends on the dynamics of the disk: whether it undergoes librating or circulating nodal precession, with librating disks evolving to polar inclinations and circulating disks evolving to coplanar. We quantify the fraction of binary star systems whose disks are expected to have polar orbits f _polar , extending previous work to include disks with nonzero mass. Our results suggest that, for low mass disks, the polar fraction is highly sensitive to the distribution of binary eccentricity, with a higher fraction expected for higher binary eccentricities, f _polar ∼ e _b . However, for massive disks, the fraction is independent of the binary eccentricity and f _polar ≈ 0.37. The value of f _polar is always reduced in a population with a greater preference for low initial mutual inclination. We also explore the consequences of the finite lifetime and nonzero radial extent of a real disk, both of which affect a disk’s ability to complete its evolution to a stationary configuration. Our findings can be used to make predictions given populations with well-understood distributions of binary eccentricity, initial mutual inclination, and disk angular momentum.https://doi.org/10.3847/1538-3881/adde5dBinary starsStellar accretion disksN-body simulations |
| spellingShingle | Ted M. Johnson Rebecca G. Martin Stephen Lepp Stephen H. Lubow The Fraction of Polar-aligned Circumbinary Disks The Astronomical Journal Binary stars Stellar accretion disks N-body simulations |
| title | The Fraction of Polar-aligned Circumbinary Disks |
| title_full | The Fraction of Polar-aligned Circumbinary Disks |
| title_fullStr | The Fraction of Polar-aligned Circumbinary Disks |
| title_full_unstemmed | The Fraction of Polar-aligned Circumbinary Disks |
| title_short | The Fraction of Polar-aligned Circumbinary Disks |
| title_sort | fraction of polar aligned circumbinary disks |
| topic | Binary stars Stellar accretion disks N-body simulations |
| url | https://doi.org/10.3847/1538-3881/adde5d |
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