A Fourth Planet in the Kepler-51 System Revealed by Transit Timing Variations

Abstract Kepler-51 is a ≲1 Gyr old Sun-like star hosting three transiting planets with radii ≈6–9 R ⊕ and orbital periods ≈45–130 days. Transit timing variations (TTVs) measured with past Kepler and Hubble Space Telescope (HST) observations have been successfully modeled by considering gravitational interactions between the three transiting planets, yielding low masses and low mean densities (≲0.1 g cm −3 ) for all three planets. However, the transit time of the outermost transiting planet Kepler-51d recently measured by the James Webb Space Telescope 10 yr after the Kepler observations is significantly discrepant from the prediction made by the three-planet TTV model, which we confirmed with ground-based and follow-up HST observations. We show that the departure from the three-planet model is explained by including a fourth outer planet, Kepler-51e, in the TTV model. A wide range of masses (≲ M Jup ) and orbital periods (≲10 yr) are possible for Kepler-51e. Nevertheless, all the coplanar solutions found from our brute-force search imply masses ≲10 M ⊕ for the inner transiting planets. Thus, their densities remain low, though with larger uncertainties than previously estimated. Unlike other possible solutions, the one in which Kepler-51e is around the 2:1 mean motion resonance with Kepler-51d implies low orbital eccentricities (≲0.05) and comparable masses (∼5 M ⊕ ) for all four planets, as is seen in other compact multiplanet systems. This work demonstrates the importance of long-term follow-up of TTV systems for probing longer-period planets in a system.

Authors

Publication Details

Journal
The Astronomical Journal
Published
2024-12-01
DOI
https://doi.org/10.3847/1538-3881/ad83d3
Citations
14
Primary Topic
Stellar, planetary, and galactic studies
Type
article
Field-Weighted Citation Impact
4.64

Funders

Controls
|||
ALL TIME
JAN
FEB
MAR
APR
MAY
JUN
JUL
AUG
SEP
OCT
article

A Fourth Planet in the Kepler-51 System Revealed by Transit Timing Variations

Michael Greklek-McKeon, Éric Girardin, H. V. Şenavcı, Richard Freedman et al.
14 citations
The Astronomical Journal
Stellar, planetary, and galactic studies
4.64
article

A Fourth Planet in the Kepler-51 System Revealed by Transit Timing Variations

Michael Greklek-McKeon, Éric Girardin, H. V. Şenavcı, Richard Freedman, K. Masuda, Gavin Wang, M. Gillon, C. A. Murray, F. J. Pozuelos, Zachory K. Berta-Thompson, F. Murgas, Shreyas Vissapragada, Akihiko Fukui, Ε. Πάλλη, Kevin B. Stevenson, Caleb I. Cañas, Guangwei Fu, Emmanuël Jehin, M. Yılmaz, Luis Welbanks, Heather A. Knutson, Kazumasa Ohno, H. Parviainen, Jessica E. Libby-Roberts, Karen A. Collins, Renyu Hu, Z. Benkhaldoun, G. Marino, Daniel Jontof‐Hutter, Peter Gao, Te Han, John H. Livingston, Khalid Barkaoui, Jerome de Leon, Andrea S. J. Lin, Armen Tokadjian, Paul Benni, Guđmundur Stefánsson, Aaron Bello-Arufe, Suzanne L. Hawley, Yui Kawashima, Caroline Morley, Leslie Hebb, Matthew C. Nixon, Yayaati Chachan, Norio Narita, Suvrath Mahadevan, Eric Agol, E. Esparza-Borges, Allyson Bieryla, Xi Zhang, M. Mori
article en
14 citations

Abstract

Abstract Kepler-51 is a ≲1 Gyr old Sun-like star hosting three transiting planets with radii ≈6–9 R ⊕ and orbital periods ≈45–130 days. Transit timing variations (TTVs) measured with past Kepler and Hubble Space Telescope (HST) observations have been successfully modeled by considering gravitational interactions between the three transiting planets, yielding low masses and low mean densities (≲0.1 g cm −3 ) for all three planets. However, the transit time of the outermost transiting planet Kepler-51d recently measured by the James Webb Space Telescope 10 yr after the Kepler observations is significantly discrepant from the prediction made by the three-planet TTV model, which we confirmed with ground-based and follow-up HST observations. We show that the departure from the three-planet model is explained by including a fourth outer planet, Kepler-51e, in the TTV model. A wide range of masses (≲ M Jup ) and orbital periods (≲10 yr) are possible for Kepler-51e. Nevertheless, all the coplanar solutions found from our brute-force search imply masses ≲10 M ⊕ for the inner transiting planets. Thus, their densities remain low, though with larger uncertainties than previously estimated. Unlike other possible solutions, the one in which Kepler-51e is around the 2:1 mean motion resonance with Kepler-51d implies low orbital eccentricities (≲0.05) and comparable masses (∼5 M ⊕ ) for all four planets, as is seen in other compact multiplanet systems. This work demonstrates the importance of long-term follow-up of TTV systems for probing longer-period planets in a system.

The Astronomical JournalVol. 168(6)
Space Telescope Science Institute, Japan Society for the Promotion of Science
Openalex Percentile: Top 5%
Stellar, planetary, and galactic studies
4.64
DOIOpen Access PDFOpenAlex
AI Navigator

Ask Laika to Summarize, Analyze, and Connect papers live on the map.

Summarize Papers & Methodologies

Extract key findings, datasets, and comparative methods across publications.

Benchmark Rankings & Visual Analytics

Rank top research institutions, authors, funders, topics, and journals by Field-Weighted Citation Impact (FWCI) and paper volume with instant charts.

Connect Distant Disciplines

Bridge topological clusters on the map to find hidden collaborative intersections.