The Astronomical Journal (Jan 2024)
A Fourth Planet in the Kepler-51 System Revealed by Transit Timing Variations
- Kento Masuda,
- Jessica E. Libby-Roberts,
- John H. Livingston,
- Kevin B. Stevenson,
- Peter Gao,
- Shreyas Vissapragada,
- Guangwei Fu,
- Te Han,
- Michael Greklek-McKeon,
- Suvrath Mahadevan,
- Eric Agol,
- Aaron Bello-Arufe,
- Zachory Berta-Thompson,
- Caleb I. Cañas,
- Yayaati Chachan,
- Leslie Hebb,
- Renyu Hu,
- Yui Kawashima,
- Heather A. Knutson,
- Caroline V. Morley,
- Catriona A. Murray,
- Kazumasa Ohno,
- Armen Tokadjian,
- Xi Zhang,
- Luis Welbanks,
- Matthew C. Nixon,
- Richard Freedman,
- Norio Narita,
- Akihiko Fukui,
- Jerome P. de Leon,
- Mayuko Mori,
- Enric Palle,
- Felipe Murgas,
- Hannu Parviainen,
- Emma Esparza-Borges,
- Daniel Jontof-Hutter,
- Karen A. Collins,
- Paul Benni,
- Khalid Barkaoui,
- Francisco J. Pozuelos,
- Michaël Gillon,
- Emmanuël Jehin,
- Zouhair Benkhaldoun,
- Suzanne Hawley,
- Andrea S. J. Lin,
- Guđmundur Stefánsson,
- Allyson Bieryla,
- Mesut Yilmaz,
- Hakan Volkan Senavci,
- Eric Girardin,
- Giuseppe Marino,
- Gavin Wang
Affiliations
- Kento Masuda
- ORCiD
- Department of Earth and Space Science, Osaka University , Osaka 560-0043, Japan ; [email protected]
- Jessica E. Libby-Roberts
- ORCiD
- Department of Astronomy & Astrophysics, 525 Davey Laboratory, The Pennsylvania State University , University Park, PA 16802, USA; Center for Exoplanets and Habitable Worlds, 525 Davey Laboratory, The Pennsylvania State University , University Park, PA 16802, USA
- John H. Livingston
- ORCiD
- Astrobiology Center , 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan; National Astronomical Observatory of Japan , 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan; Astronomical Science Program, Graduate University for Advanced Studies , SOKENDAI, 2-21-1, Osawa, Mitaka, Tokyo, 181-8588, Japan
- Kevin B. Stevenson
- ORCiD
- JHU Applied Physics Laboratory , 11100 Johns Hopkins Road, Laurel, MD 20723, USA
- Peter Gao
- ORCiD
- Carnegie Science Earth and Planets Laboratory , 5241 Broad Branch Road, NW, Washington, DC 20015, USA
- Shreyas Vissapragada
- ORCiD
- Carnegie Science Observatories , 813 Santa Barbara Street, Pasadena, CA 91101, USA
- Guangwei Fu
- ORCiD
- Department of Physics and Astronomy, Johns Hopkins University , Baltimore, MD, USA
- Te Han
- ORCiD
- Department of Physics & Astronomy, The University of California , Irvine, Irvine, CA 92697, USA
- Michael Greklek-McKeon
- ORCiD
- Division of Geological and Planetary Sciences, California Institute of Technology , Pasadena, CA 91125, USA
- Suvrath Mahadevan
- ORCiD
- Department of Astronomy & Astrophysics, 525 Davey Laboratory, The Pennsylvania State University , University Park, PA 16802, USA; Center for Exoplanets and Habitable Worlds, 525 Davey Laboratory, The Pennsylvania State University , University Park, PA 16802, USA
- Eric Agol
- ORCiD
- Department of Astronomy, University of Washington , Seattle, WA 98195, USA
- Aaron Bello-Arufe
- ORCiD
- Jet Propulsion Laboratory, California Institute of Technology , Pasadena, CA 91011, USA
- Zachory Berta-Thompson
- ORCiD
- Department of Astrophysical and Planetary Sciences, University of Colorado Boulder , Boulder, CO 80309, USA
- Caleb I. Cañas
- ORCiD
- NASA Goddard Space Flight Center , 8800 Greenbelt Road, Greenbelt, MD 20771, USA
- Yayaati Chachan
- ORCiD
- Department of Physics and Trottier Space Institute, McGill University , 3600 rue University, H3A 2T8 Montréal, QC, Canada; Trottier Institute for Research on Exoplanets (iREx), Université de Montréal , QC, H3C 3J7, Canada
- Leslie Hebb
- ORCiD
- Hobart and William Smith Colleges , Geneva, NY 14456, USA; Cornell University , Ithaca, NY 14853, USA
- Renyu Hu
- ORCiD
- Division of Geological and Planetary Sciences, California Institute of Technology , Pasadena, CA 91125, USA; Jet Propulsion Laboratory, California Institute of Technology , Pasadena, CA 91011, USA
- Yui Kawashima
- ORCiD
- Frontier Research Institute for Interdisciplinary Sciences, Tohoku University , 6-3 Aramaki aza Aoba, Aoba-ku, Sendai, Miyagi 980-8578, Japan; Department of Geophysics, Graduate School of Science, Tohoku University , 6-3 Aramaki aza Aoba, Aoba-ku, Sendai, Miyagi 980-8578, Japan; Cluster for Pioneering Research , RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
- Heather A. Knutson
- ORCiD
- Department of Earth and Planetary Sciences, University of California Santa Cruz , Santa Cruz, CA, USA
- Caroline V. Morley
- ORCiD
- Department of Astronomy, University of Texas at Austin , Austin, TX 78722, USA
- Catriona A. Murray
- ORCiD
- Department of Astrophysical and Planetary Sciences, University of Colorado Boulder , Boulder, CO 80309, USA
- Kazumasa Ohno
- ORCiD
- Division of Science, National Astronomical Observatory of Japan , 2-21-1 Osawa, Mitaka-shi, Tokyo, Japan
- Armen Tokadjian
- ORCiD
- Jet Propulsion Laboratory, California Institute of Technology , Pasadena, CA 91011, USA
- Xi Zhang
- ORCiD
- Department of Earth and Planetary Sciences, University of California Santa Cruz , Santa Cruz, CA, USA
- Luis Welbanks
- ORCiD
- School of Earth and Space Exploration, Arizona State University , Tempe, AZ, USA
- Matthew C. Nixon
- ORCiD
- Department of Astronomy, University of Maryland , College Park, MD, USA
- Richard Freedman
- ORCiD
- SETI Institute , NASA Ames Research Center, Mountain View, CA 94043, USA
- Norio Narita
- ORCiD
- Astrobiology Center , 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan; Komaba Institute for Science, The University of Tokyo , 3-8-1 Komaba, Meguro, Tokyo 153-8902, Japan; Instituto de Astrofísica de Canarias (IAC) , 38205 La Laguna, Tenerife, Spain
- Akihiko Fukui
- ORCiD
- Komaba Institute for Science, The University of Tokyo , 3-8-1 Komaba, Meguro, Tokyo 153-8902, Japan; Instituto de Astrofísica de Canarias (IAC) , 38205 La Laguna, Tenerife, Spain
- Jerome P. de Leon
- ORCiD
- Department of Multi-Disciplinary Sciences, Graduate School of Arts and Sciences, The University of Tokyo , 3-8-1 Komaba, Meguro, Tokyo 153-8902, Japan
- Mayuko Mori
- ORCiD
- Astrobiology Center, 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan National Astronomical Observatory of Japan , 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan
- Enric Palle
- ORCiD
- Instituto de Astrofísica de Canarias (IAC) , Calle Vía Láctea s/n, 38200, La Laguna, Tenerife, Spain
- Felipe Murgas
- ORCiD
- Instituto de Astrofísica de Canarias (IAC) , Calle Vía Láctea s/n, 38200, La Laguna, Tenerife, Spain; Departamento de Astrofísica, Universidad de La Laguna , E-38206 La Laguna, Tenerife, Spain
- Hannu Parviainen
- ORCiD
- Instituto de Astrofísica de Canarias (IAC) , Calle Vía Láctea s/n, 38200, La Laguna, Tenerife, Spain; Departamento de Astrofísica, Universidad de La Laguna , E-38206 La Laguna, Tenerife, Spain
- Emma Esparza-Borges
- ORCiD
- Instituto de Astrofísica de Canarias (IAC) , Calle Vía Láctea s/n, 38200, La Laguna, Tenerife, Spain; Departamento de Astrofísica, Universidad de La Laguna , E-38206 La Laguna, Tenerife, Spain
- Daniel Jontof-Hutter
- ORCiD
- Department of Physics and Astronomy, University of the Pacific , 601 Pacific Avenue, Stockton, CA 95211, USA
- Karen A. Collins
- ORCiD
- Center for Astrophysics ∣ Harvard & Smithsonian , 60 Garden Street, Cambridge, MA 02138, USA
- Paul Benni
- ORCiD
- Acton Sky Portal (private observatory) , Acton, MA 01720, USA
- Khalid Barkaoui
- ORCiD
- Instituto de Astrofísica de Canarias (IAC) , Calle Vía Láctea s/n, 38200, La Laguna, Tenerife, Spain; Astrobiology Research Unit, University of Liège , Allée du 6 août, 19, 4000 Liège (Sart-Tilman), Belgium; Department of Earth, Atmospheric and Planetary Sciences , MIT, 77 Massachusetts Avenue, Cambridge, MA 02139, USA
- Francisco J. Pozuelos
- ORCiD
- Instituto de Astrofísica de Andalucía (IAA-CSIC) , Glorieta de la Astronomía s/n, 18008 Granada, Spain
- Michaël Gillon
- ORCiD
- Astrobiology Research Unit, University of Liège , Allée du 6 août, 19, 4000 Liège (Sart-Tilman), Belgium
- Emmanuël Jehin
- ORCiD
- STAR Institute, University of Liège , Allée du 6 août, 19, 4000 Liège (Sart-Tilman), Belgium
- Zouhair Benkhaldoun
- ORCiD
- Oukaimeden Observatory, High Energy Physics and Astrophysics Laboratory, Cadi Ayyad University , Marrakech, Morocco
- Suzanne Hawley
- ORCiD
- Department of Astronomy, Box 351580, University of Washington , Seattle, WA 98195, USA
- Andrea S. J. Lin
- ORCiD
- Department of Astronomy & Astrophysics, 525 Davey Laboratory, The Pennsylvania State University , University Park, PA 16802, USA; Center for Exoplanets and Habitable Worlds, 525 Davey Laboratory, The Pennsylvania State University , University Park, PA 16802, USA
- Guđmundur Stefánsson
- ORCiD
- Anton Pannekoek Institute for Astronomy, University of Amsterdam , Science Park 904, 1098 XH Amsterdam, The Netherlands
- Allyson Bieryla
- ORCiD
- Center for Astrophysics ∣ Harvard & Smithsonian , 60 Garden Street, Cambridge, MA 02138, USA
- Mesut Yilmaz
- ORCiD
- Ankara University , Department of Astronomy and Space Sciences, TR-06100, Ankara, Türkiye; Ankara University , Astronomy and Space Sciences Research and Application Center (Kreiken Observatory), İncek Blvd., TR-06837, Ahlatlıbel, Ankara, Türkiye
- Hakan Volkan Senavci
- ORCiD
- Ankara University , Department of Astronomy and Space Sciences, TR-06100, Ankara, Türkiye; Ankara University , Astronomy and Space Sciences Research and Application Center (Kreiken Observatory), İncek Blvd., TR-06837, Ahlatlıbel, Ankara, Türkiye
- Eric Girardin
- ORCiD
- Grand-Pra Observatory , 1984 Les Hauderes, Switzerland
- Giuseppe Marino
- ORCiD
- Wild Boar Remote Observatory , San Casciano in val di Pesa, Firenze 50026, Italy
- Gavin Wang
- ORCiD
- Department of Physics & Astronomy, Johns Hopkins University , 3400 N. Charles Street, Baltimore, MD 21218, USA
- DOI
- https://doi.org/10.3847/1538-3881/ad83d3
- Journal volume & issue
-
Vol. 168,
no. 6
p. 294
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.
Keywords
- Exoplanet astronomy
- Hubble Space Telescope
- Transit photometry
- Transit timing variation method
- Transits
- James Webb Space Telescope
