RV and TTV Measurements of Two Transiting Long-Period Giants around TOI-4600
Tong Hu, Zitao Lin, Sharon X. Wang, Mu-Tian Wang, Ismael Mireles + 25 more
TLDR
New observations refine parameters and detect significant transit timing variations for the long-period giant exoplanets TOI-4600b and c.
Key contributions
- Refined orbital parameters (masses, eccentricities) for exoplanets TOI-4600b and c using new TESS and RV data.
- Precisely measured TOI-4600b's mass (74.7 Mₓ) and eccentricity (0.153), and TOI-4600c's mass (212.5 Mₓ) and eccentricity (0.219).
- Discovered significant transit timing variations (~1 hour semi-amplitude) for both TOI-4600b and TOI-4600c.
- Identified TOI-4600b and c as promising JWST targets for studying temperate/cold Jupiter atmospheres.
Why it matters
These updated parameters and TTV ephemerides are crucial for future photometric, spectroscopic, and dynamical studies of the TOI-4600 system. The planets are also identified as prime JWST targets for characterizing the atmospheres of rare temperate and cold Jupiters. This work advances our understanding of long-period giant exoplanets.
Original Abstract
TOI-4600b and c, originally identified by the Transiting Exoplanet Survey Satellite (TESS) and reported by I. Mireles et al. (2023), are a rare pair of transiting long-period giant planets ($\rm P_b=82.7$ days, $\rm P_c=482.8$ days) orbiting an early K dwarf. In this work, we refine the orbital parameters of the TOI-4600 system by combining new TESS photometry, ground-based transit follow-up, and radial velocity (RV) observations from MAROON-X. We obtain improved constraints on planetary masses and eccentricities, and update other parameters, such as the stellar age. For TOI-4600b, we measure a mass of $M_p = 74.7^{+4.7}_{-4.4}\,M_{\oplus}$ and an eccentricity of $e=0.153^{+0.020}_{-0.018}$, and $M_p = 212.53^{+13.26}_{-13.03}\,M_{\oplus}$ and $e=0.219^{+0.015}_{-0.018}$ for TOI-4600c. We find significant transit timing variations (TTV) in both planets, with semi-amplitudes of approximately $1$\,hr. We derive Transit Spectroscopy Metric values of 16.87 for TOI-4600b and 10.09 for TOI-4600c, indicating that both planets are promising JWST targets for studying the atmospheres of temperate and cold Jupiters, a relatively poorly characterized sample thus far. These updated parameters and TTV ephemerides are important for planning and interpreting future photometric, spectroscopic, and dynamical studies of the TOI-4600 system.
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