Orbital Decay of the Ultra-hot Jupiter TOI-2109b: Tidal Constraints and Transit-timing Analysis
TOI-2109b is the ultra-hot Jupiter with the shortest orbital period (∼16 hr) yet discovered. At this close distance, strong tidal interactions can produce a significant exchange of angular momentum with the star. Since the orbital period of this planet is shorter than the stellar rotation period, TO...
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2025-01-01
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| Series: | The Astrophysical Journal |
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| Online Access: | https://doi.org/10.3847/1538-4357/ade057 |
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| author | Jaime A. Alvarado-Montes Mario Sucerquia Jorge I. Zuluaga Christian Schwab |
| author_facet | Jaime A. Alvarado-Montes Mario Sucerquia Jorge I. Zuluaga Christian Schwab |
| author_sort | Jaime A. Alvarado-Montes |
| collection | DOAJ |
| description | TOI-2109b is the ultra-hot Jupiter with the shortest orbital period (∼16 hr) yet discovered. At this close distance, strong tidal interactions can produce a significant exchange of angular momentum with the star. Since the orbital period of this planet is shorter than the stellar rotation period, TOI-2109b may be an optimal candidate for studying orbital decay. This process depends on how efficiently the star and the planet dissipate energy, due mainly to interior mechanisms that are poorly constrained in exoplanet systems. In this work, we study for the first time the tidal evolution of TOI-2109b under a formalism of inertial waves (IWs) in convective envelopes and internal gravity waves (IGWs) in stellar radiative regions. We find that uncertainties in the age of TOI-2109 ( t _⋆,age ) significantly affect the rate of orbital evolution, as IWs and IGWs interact differently depending on t _⋆,age . For an “old” host star, we find that TOI-2109b would undergo fast orbital decay. Conversely, if TOI-2109b orbits a “young” host star, a rather slow decay rate for ${Q}_{\star }^{{\prime} }\gt 2.3\times 1{0}^{7}$ would suggest a constant-period orbit. Our calculated mid-transit times and transit-timing variations (TTVs) support a “young” host star with ${Q}_{\star }^{{\prime} }\gt 3.7\times 1{0}^{7}$ , suggesting a decay rate $\dot{P}\sim 4\,{\rm{ms}}\,{{\rm{yr}}}^{-1}$ that could lead to mid-transit-time shifts ≲10 s over three years. Orbital decay and other TTV-inducing effects will be confirmed or ruled out with future higher-quality timing data. The results presented here aim at constraining the current modeling of tides and TTVs for TOI-2109b, helping us further understand light-curve changes associated with the long-term evolution of ultra-short-period planets. |
| format | Article |
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| institution | DOAJ |
| issn | 1538-4357 |
| language | English |
| publishDate | 2025-01-01 |
| publisher | IOP Publishing |
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| series | The Astrophysical Journal |
| spelling | doaj-art-ec251cddd5e946579c3104d1570f48862025-08-20T02:39:19ZengIOP PublishingThe Astrophysical Journal1538-43572025-01-0198816610.3847/1538-4357/ade057Orbital Decay of the Ultra-hot Jupiter TOI-2109b: Tidal Constraints and Transit-timing AnalysisJaime A. Alvarado-Montes0https://orcid.org/0000-0003-0353-9741Mario Sucerquia1https://orcid.org/0000-0002-8065-4199Jorge I. Zuluaga2https://orcid.org/0000-0002-6140-3116Christian Schwab3https://orcid.org/0000-0002-4046-987XAustralian Astronomical Optics, Macquarie University , Balaclava Road, Sydney, NSW 2109, Australia ; jaime.alvaradomontes@mq.edu.au; Astrophysics and Space Technologies Research Centre, Macquarie University , Balaclava Road, Sydney, NSW 2109, AustraliaUniversité Grenoble Alpes , CNRS, IPAG, 38000 Grenoble, FranceSEAP/FACom, Instituto de Física—FCEN, Universidad de Antioquia , Calle 70 No. 52-21, Medellín, ColombiaSchool of Mathematical and Physical Sciences, Macquarie University , Balaclava Road, Sydney, NSW 2109, AustraliaTOI-2109b is the ultra-hot Jupiter with the shortest orbital period (∼16 hr) yet discovered. At this close distance, strong tidal interactions can produce a significant exchange of angular momentum with the star. Since the orbital period of this planet is shorter than the stellar rotation period, TOI-2109b may be an optimal candidate for studying orbital decay. This process depends on how efficiently the star and the planet dissipate energy, due mainly to interior mechanisms that are poorly constrained in exoplanet systems. In this work, we study for the first time the tidal evolution of TOI-2109b under a formalism of inertial waves (IWs) in convective envelopes and internal gravity waves (IGWs) in stellar radiative regions. We find that uncertainties in the age of TOI-2109 ( t _⋆,age ) significantly affect the rate of orbital evolution, as IWs and IGWs interact differently depending on t _⋆,age . For an “old” host star, we find that TOI-2109b would undergo fast orbital decay. Conversely, if TOI-2109b orbits a “young” host star, a rather slow decay rate for ${Q}_{\star }^{{\prime} }\gt 2.3\times 1{0}^{7}$ would suggest a constant-period orbit. Our calculated mid-transit times and transit-timing variations (TTVs) support a “young” host star with ${Q}_{\star }^{{\prime} }\gt 3.7\times 1{0}^{7}$ , suggesting a decay rate $\dot{P}\sim 4\,{\rm{ms}}\,{{\rm{yr}}}^{-1}$ that could lead to mid-transit-time shifts ≲10 s over three years. Orbital decay and other TTV-inducing effects will be confirmed or ruled out with future higher-quality timing data. The results presented here aim at constraining the current modeling of tides and TTVs for TOI-2109b, helping us further understand light-curve changes associated with the long-term evolution of ultra-short-period planets.https://doi.org/10.3847/1538-4357/ade057Hot JupitersTidal frictionTidal interactionExoplanet astronomyTransit timing variation method |
| spellingShingle | Jaime A. Alvarado-Montes Mario Sucerquia Jorge I. Zuluaga Christian Schwab Orbital Decay of the Ultra-hot Jupiter TOI-2109b: Tidal Constraints and Transit-timing Analysis The Astrophysical Journal Hot Jupiters Tidal friction Tidal interaction Exoplanet astronomy Transit timing variation method |
| title | Orbital Decay of the Ultra-hot Jupiter TOI-2109b: Tidal Constraints and Transit-timing Analysis |
| title_full | Orbital Decay of the Ultra-hot Jupiter TOI-2109b: Tidal Constraints and Transit-timing Analysis |
| title_fullStr | Orbital Decay of the Ultra-hot Jupiter TOI-2109b: Tidal Constraints and Transit-timing Analysis |
| title_full_unstemmed | Orbital Decay of the Ultra-hot Jupiter TOI-2109b: Tidal Constraints and Transit-timing Analysis |
| title_short | Orbital Decay of the Ultra-hot Jupiter TOI-2109b: Tidal Constraints and Transit-timing Analysis |
| title_sort | orbital decay of the ultra hot jupiter toi 2109b tidal constraints and transit timing analysis |
| topic | Hot Jupiters Tidal friction Tidal interaction Exoplanet astronomy Transit timing variation method |
| url | https://doi.org/10.3847/1538-4357/ade057 |
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