HARPS-N Reveals a Well-aligned Orbit for the Highly Eccentric Warm Jupiter TOI-4127 b

Abstract

While many hot Jupiter systems have a measured obliquity, few warm Jupiter systems do. The longer orbital periods and transit durations of warm Jupiters make it more difficult to measure the obliquities of their host stars. However, the longer periods also mean any misalignments persist due to the longer tidal realignment timescales. As a result, measuring these obliquities is necessary to understand how these types of planets form and how their formation and evolution differ from that of hot Jupiters. Here, we report the measurement of the Rossiter-McLaughlin effect for the TOI-4127 system using the HARPS-N spectrograph. We model the system using our new HARPS-N radial velocity measurements in addition to archival TESS photometry and NEID and SOPHIE radial velocities. We find that the host star is well-aligned with the highly eccentric (e=0.75) warm Jupiter TOI-4127 b, with a sky-projected obliquity $\lambda ={4^{\circ }}_{-16^{\circ }}^{+17^{\circ }}$. This makes TOI-4127 one of the most eccentric well-aligned systems to date and one of the longest period systems with a measured obliquity. Conclusions. The origin of its highly eccentric yet well-aligned orbit remains a mystery, however, and we investigate possible scenarios that could explain it. While typical in-situ formation and disk migration scenarios cannot explain this system, certain scenarios involving resonant interactions between the planet and protoplanetary disc could. Similarly, specific cases of planet-planet scattering or Kozai-Lidov oscillations can result in a highly-eccentric and well-aligned orbit. Coplanar high-eccentricity migration could also explain this system. However, both this mechanism and Kozai-Lidov oscillations require an additional planet in the system that has not yet been detected.

arXiv commentSubmitted to A&A

References in corpus (36)

• Gaia Data Release 3: Summary of the content and survey properties
• The Transiting Exoplanet Survey Satellite
• Gaia Data Release 2: The astrometric solution
• Shrinking binary and planetary orbits by Kozai cycles with tidal friction
• Kepler Presearch Data Conditioning II - A Bayesian Approach to Systematic Error Correction
• Kepler Presearch Data Conditioning I - Architecture and Algorithms for Error Correction in Kepler Light Curves
• Hot Stars with Hot Jupiters Have High Obliquities
• The TESS Input Catalog and Candidate Target List
• Obliquities of Hot Jupiter host stars: Evidence for tidal interactions and primordial misalignments
• The CORALIE survey for southern extra-solar planets VII. Two short-period Saturnian companions to HD108147 and HD168746
• Homogeneous studies of transiting extrasolar planets. IV. Thirty systems with space-based light curves
• RadVel: The Radial Velocity Modeling Toolkit
• The Rossiter-McLaughlin effect and analytic radial velocity curves for transiting extrasolar planetary systems
• Precision Stellar Characterization of FGKM Stars using an Empirical Spectral Library
• Determining stellar macroturbulence using asteroseismic rotational velocities from Kepler
• PyTransit: Fast and Easy Exoplanet Transit Modelling in Python
• Warm Jupiters are less lonely than hot Jupiters: close neighbours
• Hot Jupiters from Coplanar High-eccentricity Migration
• Improved Modeling of the Rossiter-McLaughlin Effect for Transiting Exoplanets
• ELLC - a fast, flexible light curve model for detached eclipsing binary stars and transiting exoplanets
• Warm Jupiters from secular planet-planet interactions
• The In Situ Formation of Giant Planets at Short Orbital Periods
• Scattering outcomes of close-in planets: constraints on planet migration
• Astrometric Identification of Nearby Binary Stars I: Predicted Astrometric Signals
• Spin-orbit misalignment in the HD80606 planetary system
• A backward-spinning star with two coplanar planets
• Evidence for Hidden Nearby Companions to Hot Jupiters
• A Tendency Toward Alignment in Single-Star Warm Jupiter Systems
• Characterizing Undetected Stellar Companions with Combined Datasets
• Characterization of the HD 17156 planetary system
• Ponderings on the Possible Preponderance of Perpendicular Planets
• Obliquities of Exoplanet Host Stars: 19 New and Updated Measurements, and Trends in the Sample of 205 Measurements
• Revisiting migration in a disc cavity to explain the high eccentricities of warm Jupiters
• The Aligned Orbit of the Eccentric Proto Hot Jupiter TOI-3362b
• A High-Eccentricity Warm Jupiter Orbiting TOI-4127
• Eccentricity Growth of Massive Planets inside Cavities of Protoplanetary Discs