Testing Tidal Theory Using Gaia Binaries: The Red Giant Branch
Tidal interaction is a major ingredient in the theory of binary evolution. Here, we study tidal circularization in binaries with red giant primaries. We compute the tidal evolution for binaries as their primary stars evolve along the red giant branch, under dissipation of dynamical tides in the conv...
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IOP Publishing
2025-01-01
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| Series: | The Astrophysical Journal |
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| Online Access: | https://doi.org/10.3847/1538-4357/adc37e |
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| author | Janosz W. Dewberry Yanqin Wu |
| author_facet | Janosz W. Dewberry Yanqin Wu |
| author_sort | Janosz W. Dewberry |
| collection | DOAJ |
| description | Tidal interaction is a major ingredient in the theory of binary evolution. Here, we study tidal circularization in binaries with red giant primaries. We compute the tidal evolution for binaries as their primary stars evolve along the red giant branch, under dissipation of dynamical tides in the convective envelope. We then compare this evolution with a sample of ∼30,000 red giant binaries reported by Gaia DR3. These binaries clearly show the expected gradual advance of tidal circularization, as the primary expands. But some tension with theory remains. While our calculations always predict a critical separation for tidal circularization at about 3−4 times the stellar radii, binaries with less evolved giants are observed to be circularized out to about twice as far. They also exhibit an overly extended “cool island,” a collection of circular orbits that reach a couple of times beyond the circularization limit. These discrepancies are reminiscent of, but less severe than, the situation for main-sequence binaries. We also find that tides can spin giant stars up to rotation rates that should affect their mass-loss. Additionally, many binaries may begin mass transfer while still eccentric. |
| format | Article |
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| institution | OA Journals |
| issn | 1538-4357 |
| language | English |
| publishDate | 2025-01-01 |
| publisher | IOP Publishing |
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| series | The Astrophysical Journal |
| spelling | doaj-art-e1f0aeb9db6f4fde8c33bd2d3355bde82025-08-20T02:16:05ZengIOP PublishingThe Astrophysical Journal1538-43572025-01-01984213710.3847/1538-4357/adc37eTesting Tidal Theory Using Gaia Binaries: The Red Giant BranchJanosz W. Dewberry0https://orcid.org/0000-0001-9420-5194Yanqin Wu1https://orcid.org/0000-0003-0511-0893Canadian Institute for Theoretical Astrophysics , 60 St. George Street, Toronto, ON M5S 3H8, CanadaDepartment of Astronomy & Astrophysics, University of Toronto , CanadaTidal interaction is a major ingredient in the theory of binary evolution. Here, we study tidal circularization in binaries with red giant primaries. We compute the tidal evolution for binaries as their primary stars evolve along the red giant branch, under dissipation of dynamical tides in the convective envelope. We then compare this evolution with a sample of ∼30,000 red giant binaries reported by Gaia DR3. These binaries clearly show the expected gradual advance of tidal circularization, as the primary expands. But some tension with theory remains. While our calculations always predict a critical separation for tidal circularization at about 3−4 times the stellar radii, binaries with less evolved giants are observed to be circularized out to about twice as far. They also exhibit an overly extended “cool island,” a collection of circular orbits that reach a couple of times beyond the circularization limit. These discrepancies are reminiscent of, but less severe than, the situation for main-sequence binaries. We also find that tides can spin giant stars up to rotation rates that should affect their mass-loss. Additionally, many binaries may begin mass transfer while still eccentric.https://doi.org/10.3847/1538-4357/adc37eBinary starsTidesHydrodynamicsStellar evolution |
| spellingShingle | Janosz W. Dewberry Yanqin Wu Testing Tidal Theory Using Gaia Binaries: The Red Giant Branch The Astrophysical Journal Binary stars Tides Hydrodynamics Stellar evolution |
| title | Testing Tidal Theory Using Gaia Binaries: The Red Giant Branch |
| title_full | Testing Tidal Theory Using Gaia Binaries: The Red Giant Branch |
| title_fullStr | Testing Tidal Theory Using Gaia Binaries: The Red Giant Branch |
| title_full_unstemmed | Testing Tidal Theory Using Gaia Binaries: The Red Giant Branch |
| title_short | Testing Tidal Theory Using Gaia Binaries: The Red Giant Branch |
| title_sort | testing tidal theory using gaia binaries the red giant branch |
| topic | Binary stars Tides Hydrodynamics Stellar evolution |
| url | https://doi.org/10.3847/1538-4357/adc37e |
| work_keys_str_mv | AT janoszwdewberry testingtidaltheoryusinggaiabinariestheredgiantbranch AT yanqinwu testingtidaltheoryusinggaiabinariestheredgiantbranch |