Giant Outer Transiting Exoplanet Mass (GOT 'EM) Survey. VI: Confirmation of a Long-Period Giant Planet Discovered with a Single TESS Transit

Abstract

We report the discovery and confirmation of TOI-4465 b, a $1.25_{-0.07}^{+0.08}{R}_J$, $5.89\pm 0.26M_J$ giant planet orbiting a G dwarf star at $d\simeq$ 122 pc. The planet was detected as a single-transit event in data from Sector 40 of the Transiting Exoplanet Survey Satellite (TESS) mission. Radial velocity (RV) observations of TOI-4465 showed a planetary signal with an orbital period of $\sim$102 days, and an orbital eccentricity of $e=0.24\pm 0.01$. TESS re-observed TOI-4465 in Sector 53 and Sector 80, but did not detect another transit of TOI-4465 b, as the planet was not expected to transit during these observations based on the RV period. A global ground-based photometry campaign was initiated to observe another transit of TOI-4465 b after the RV period determination. The $\sim$12 hour-long transit event was captured from multiple sites around the world, and included observations from 24 citizen scientists, confirming the orbital period as $\sim$102 days. TOI-4465 b is a relatively dense ($3.73\pm 0.53g/c{\mathrm{m}}^3$), temperate (375-478 K) giant planet. Based on giant planet structure models, TOI-4465 b appears to be enriched in heavy elements at a level consistent with late-stage accretion of icy planetesimals. Additionally, we explore TOI-4465 b's potential for atmospheric characterization, and obliquity measurement. Increasing the number of long-period planets by confirming single-transit events is crucial for understanding the frequency and demographics of planet populations in the outer regions of planetary systems.

31 pages, 13 figures, 12 tables. Accepted for publication in The Astronomical Journal

References in corpus (39)

• The Transiting Exoplanet Survey Satellite
• Estimating distances from parallaxes. V: Geometric and photogeometric distances to 1.47 billion stars in Gaia Early Data Release 3
• Improved Age Estimation for Solar-Type Dwarfs Using Activity-Rotation Diagnostics
• Accurate, Empirical Radii and Masses of Planets and their Host Stars with Gaia Parallaxes
• The TESS Objects of Interest Catalog from the TESS Prime Mission
• The imprint of exoplanet formation history on observable present-day spectra of hot Jupiters
• Gaia Early Data Release 3: The Gaia Catalogue of Nearby Stars
• Precision Stellar Characterization of FGKM Stars using an Empirical Spectral Library
• Origin of water in the inner Solar System: Planetesimals scattered inward during Jupiter and Saturn's rapid gas accretion
• Parallax Systematics and Photocenter Motions of Benchmark Eclipsing Binaries in Gaia EDR3
• The Kepler Follow-Up Observation Program. I. A Catalog of Companions to Kepler Stars from High-Resolution Imaging
• Photo-astrometric distances, extinctions, and astrophysical parameters for Gaia EDR3 stars brighter than G=18.5
• Eclipsing Binary Stars as Benchmarks for Trigonometric Parallaxes in the Gaia Era
• Empirical, Accurate Masses and Radii of Single Stars with TESS and Gaia
• Cool Jupiters greatly outnumber their toasty siblings: Occurrence rates from the Anglo-Australian Planet Search
• Beyond Equilibrium Temperature: How the Atmosphere/Interior Connection Affects the Onset of Methane, Ammonia, and Clouds in Warm Transiting Giant Planets
• Observational evidence for two distinct giant planet populations
• The Solar Neighborhood XLIX: Nine Giant Planets Orbiting Nearby K Dwarfs, and the CHIRON Spectrograph's Radial Velocity Performance
• Speckle Observations of TESS Exoplanet Host Stars. II. Stellar Companions at 1-1000 AU and Implications for Small Planet Detection
• Heavy metal rules. I. Exoplanet incidence and metallicity
• Sulfur Hazes in Giant Exoplanet Atmospheres: Impacts on Reflected Light Spectra
• Assessment of [Fe/H] determinations for FGK stars in spectroscopic surveys
• Planetesimal Capture in the Disk Instability Model
• A Tendency Toward Alignment in Single-Star Warm Jupiter Systems
• The Densities of Planets in Multiple Stellar Systems
• Empirical temperature- and extinction-dependent extinction coefficients for the GALEX, Pan-STARRS1, Gaia, SDSS, 2MASS, and WISE passbands
• Stellar ages, masses, extinctions and orbital parameters based on spectroscopic parameters of Gaia DR3
• Simultaneous TESS and NGTS Transit Observations of WASP-166b
• Unresolved Binary Exoplanet Host Stars Fit as Single Stars: Effects on the Stellar Parameters
• Connecting substellar and stellar formation. The role of the host star's metallicity
• Investigating the Planet-Metallicity Correlation for Hot Jupiters
• The Kepler-11 system: evolution of the stellar high-energy emission and {initial planetary} atmospheric mass fractions
• The TESS-Keck Survey. VIII. Confirmation of a Transiting Giant Planet on an Eccentric 261 day Orbit with the Automated Planet Finder Telescope
• No Timing Variations Observed in Third Transit of Snow-Line Exoplanet Kepler-421b
• Multiple Populations of Extrasolar Gas Giants
• Resolving period aliases for TESS monotransits recovered during the extended mission
• Kepler Transit Depths Contaminated by a Phantom Star
• Giant Outer Transiting Exoplanet Mass (GOT 'EM) Survey: III. Recovery and Confirmation of a Temperate, Mildly Eccentric, Single-Transit Jupiter Orbiting TOI-2010
• Revised Properties and Dynamical History for the HD 17156 System

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