New Asteroseismic Constraints on Transiting Planet Systems Observed by TESS

Grunblatt, Samuel; Saunders, Nicholas; Monroe, Tobin

doi:10.5281/zenodo.17437910

New Asteroseismic Constraints on Transiting Planet Systems Observed by TESS

Grunblatt, Samuel; Saunders, Nicholas; Monroe, Tobin

Publisher: Zenodo
DOI: 10.5281/zenodo.17437910
Repository: zenodo.org
Language: en

Abstract

Despite the hundreds of thousands of asteroseismic detections from TESS, very few asteroseismic detections of planet host stars have been made. However, additional data from the extended missions of TESS has made the detection of smaller transiting planets and solar-like asteroseismic signals easier. Here, we report the detection of TOI-7041 b, a hot Jupiter orbiting a red giant star. Our asteroseismic analysis indicates that TOI-7041 has a mass of 1.07±0.07 M⊙ and a radius of 4.10 ± 0.11 R⊙, making it one of the largest stars around which a transiting planet has been discovered with the Transiting Exoplanet Survey Satellite (TESS), and the mission's first oscillating red giant with a transiting planet. TOI-7041 b has an orbital period of 9.691±0.006 days and a low eccentricity of e = 0.04 ± 0.04. We measure a planet radius of 1.02 ± 0.03 RJup with TESS photometry, and a planet mass of 0.36±0.16 MJup (114±51 M⊕) with ground-based radial velocity measurements. TOI-7041 b appears less inflated than similar systems receiving equivalent incident flux, and its circular orbit indicates that it is not undergoing tidal heating due to circularization. The asteroseismic analysis of the host star provides some of the tightest constraints on the stellar properties of a TESS planet host and enables precise characterization of the hot Saturn. We also present two new asteroseismic constraints in two other previously confirmed systems, TOI-2669 and TOI-4551, further improving constraints on planet masses and radii and thus testing theories of planet (re-)inflation. These asteroseismic detections of planet hosts indicate that extended TESS observations of evolved stars will similarly provide a path to improved exoplanet characterization.

Full text

Samuel Grunblatt1, Nicholas Saunders2, Toby Monroe1 1. Department of Physics and Astronomy, University of Alabama, 2. Institute for Astronomy, University of Hawaii New Asteroseismic Constraints on Transiting Planet Systems Observed by TESS A targeted visual search for giant planets transiting giant stars with the giants pipeline (Saunders+ 2022) revealed a shallow (~500 ppm), long-duration (~9 hr) transit signal at a 9.7 day period around evolved target TIC 201175570, later designated TOI-7041. Additional analysis of this light curve with pySYD (Chontos+ 2022) and PBjam (Nielsen+ 2021) revealed solar-like oscillations. Additional detections improve mass, age precision, putting systems in context Key Points The most evolved TESS planetary system discovered to date An uninflated hot Saturn in a multiplanet system? ❖Though thousands of planet candidates and asteroseismic signals have been detected by TESS, only one transiting planet system discovered by TESS had an asteroseismic characterization (HD 221416 b, Huber+ 2019) before this year. ❖Here, we present TOI-7041 b (Saunders+ 2025), a transiting planet found in TESS amenable to asteroseismic characterization. ❖ We also report asteroseismic detections in TOI-2669 b and TOI-4551 b, two other transiting planets previously confirmed by TESS (Grunblatt+ 2022, Pereira+ 2024), quadrupling the size of this uniquely well-characterized TESS planet population. We then confirmed this system with RV followup from CHIRON, FEROS, and PFS. Using exoplanet (Foreman-Mackey+ 2018), we modeled the available data for this system to determine the planet mass and radius. References 1. Saunders, N., Grunblatt, S., Huber, D., Ong, J., Schlaufman, K., et al. “TESS Giants Transiting Giants. VII. A Hot Saturn Orbiting an Oscillating Red Giant Star,” AJ, 169, 75, 2025. 2. Pereira, F., Grunblatt, S., Psaridi, A., Campante, T., Cunha, M., et al. “TESS giants transiting giants V - two hot Jupiters orbiting red giant hosts,” MNRAS, 527, 6332, 2024. 3. Grunblatt, S., Saunders, N., Sun, M., Chontos, A., Soares-Furtado, M., et al. "TESS Giants Transiting Giants. II. The Hottest Jupiters Orbiting Evolved Stars,” AJ, 163, 120, 2022. By leveraging TESS Extended Mission data of evolved systems confirmed previously revealed asteroseismic signals that were not detected during system confirmation. Solar-like oscillations can now be detected in the TOI-2669 (left) and TOI-4551 (right) systems. Using pySYD, we measured νmax and Δν in these systems. We then used isoclassify to redetermine stellar radii, masses, and ages. Using isoclassify (Huber+ 2017) to combine asteroseismic, spectroscopic and photometric constraints, we measure a stellar radius of 4.10 +/- 0.11 RSun, making this the most evolved TESS planet host found to date. RV measurements revealed an additional periodic signal, suggestive of an outer planetary companion with a ~150-day orbital period. Rp = 1.02 +/- 0.02 RJup Mp = 0.36 +/- 0.16 MJup These asteroseismic constraints reveal that previous masses were overestimated by 10-20%, and ages reported were underestimated by 30-50%. This suggests these systems are closer analogs to the future of the Solar System than previously believed. Link to TOI-7041 b paper: https://arxiv.org/abs/2410.11037 (or use QR code above!) Despite TOI-7041 b’s almost identical mass and incident flux to previously discovered evolved planets, its radius suggests it is not an inflated planet. Poster #116!