Discerning Exoplanet Migration Models Using Spin-Orbit Measurements

Abstract

We investigate the current sample of exoplanet spin-orbit measurements to determine whether a dominant planet migration channel can be identified, and at what confidence. We use the predictions of Kozai migration plus tidal friction (Fabrycky and Tremaine 2007) and planet-planet scattering (Nagasawa et al. 2008) as our misalignment models, and we allow for a fraction of intrinsically aligned systems, explainable by disk migration. Bayesian model comparison demonstrates that the current sample of 32 spin-orbit measurements strongly favors a two-mode migration scenario combining planet-planet scattering and disk migration over a single-mode Kozai migration scenario. Our analysis indicates that between 34% and 76% of close-in planets (95% confidence) migrated via planet-planet scattering. Separately analyzing the subsample of 12 stars with T_eff > 6250 K---which Winn et al. (2010) predict to be the only type of stars to maintain their primordial misalignments---we find that the data favor a single-mode scattering model over Kozai with 81% confidence. We also assess the number of additional hot star spin-orbit measurements that will likely be necessary to provide a more confident model selection, finding that an additional 20-30 measurements has a >50% chance of resulting in a 95%-confident model selection, if the current model selection is correct. While we test only the predictions of particular Kozai and scattering migration models in this work, our methods may be used to test the predictions of any other spin-orbit misaligning mechanism.

9 pages, 8 figures, ApJ responded to referee

References in corpus (14)

• Dynamical Outcomes of Planet-Planet Scattering
• Hot Stars with Hot Jupiters Have High Obliquities
• Formation of Hot Planets by a combination of planet scattering, tidal circularization, and Kozai mechanism
• Origins of Eccentric Extrasolar Planets: Testing the Planet-Planet Scattering Model
• Spin-orbit angle measurements for six southern transiting planets; New insights into the dynamical origins of hot Jupiters
• Prospects for the Characterization and Confirmation of Transiting Exoplanets via the Rossiter-McLaughlin Effect
• Evidence of Possible Spin-Orbit Misalignment Along the Line of Sight in Transiting Exoplanet Systems
• Tidal Evolution of Close-in Planets
• Misaligned spin-orbit in the XO-3 planetary system?
• Hot Jupiters in binary star systems
• The Transit Light Curve Project. V. System Parameters and Stellar Rotation Period of HD 189733
• Measurement of the Spin-Orbit Alignment in the Exoplanetary System HD 189733
• On the Spin-Orbit Misalignment of the XO-3 Exoplanetary System
• The Rossiter-McLaughlin Effect of the Transiting Exoplanet XO-4b

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