Published January 2024 | Published
Journal Article Open

The Kepler Giant Planet Search. I. A Decade of Kepler Planet-host Radial Velocities from W. M. Keck Observatory

  • 1. ROR icon University of Notre Dame
  • 2. ROR icon University of Southern Queensland
  • 3. ROR icon University of California, Berkeley
  • 4. ROR icon California Institute of Technology
  • 5. ROR icon NASA Exoplanet Science Institute
  • 6. ROR icon University of California, Los Angeles
  • 7. ROR icon University of Chicago
  • 8. ROR icon University of the Pacific
  • 9. ROR icon University of Nevada, Las Vegas
  • 10. Nevada Center for Astrophysics, 4505 South Maryland Parkway, P.O. Box 454002, Las Vegas, NV 89154, USA
  • 11. ROR icon Pennsylvania State University
  • 12. ROR icon University of California, Irvine
  • 13. ROR icon University of Hawaii at Manoa
  • 14. ROR icon Princeton University
  • 15. ROR icon University of California, Riverside
  • 16. ROR icon University of California, Santa Cruz
  • 17. ROR icon Gemini North Observatory
  • 18. ROR icon University of Kansas
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Abstract

Despite the importance of Jupiter and Saturn to Earth's formation and habitability, there has not yet been a comprehensive observational study of how giant exoplanets correlate with the architectural properties of close-in, sub-Neptune-sized exoplanets. This is largely because transit surveys are particularly insensitive to planets at orbital separations ≳1 au, and so their census of Jupiter-like planets is incomplete, inhibiting our study of the relationship between Jupiter-like planets and the small planets that do transit. To investigate the relationship between close-in, small and distant, giant planets, we conducted the Kepler Giant Planet Survey (KGPS). Using the W. M. Keck Observatory High Resolution Echelle Spectrometer, we spent over a decade collecting 2844 radial velocities (RVs; 2167 of which are presented here for the first time) of 63 Sunlike stars that host 157 transiting planets. We had no prior knowledge of which systems would contain giant planets beyond 1 au, making this survey unbiased with respect to previously detected Jovians. We announce RV-detected companions to 20 stars from our sample. These include 13 Jovians (0.3 M_J < M sin ⁡i < 13 M_J, 1 au < a < 10 au), eight nontransiting sub-Saturns, and three stellar-mass companions. We also present updated masses and densities of 84 transiting planets. The KGPS project leverages one of the longest-running and most data-rich collections of RVs of the NASA Kepler systems yet, and it will provide a basis for addressing whether giant planets help or hinder the growth of sub-Neptune-sized and terrestrial planets. Future KGPS papers will examine the relationship between small, transiting planets and their long-period companions.

Copyright and License

© 2023. The Author(s). Published by the American Astronomical Society.

Original content from this work may be used under the terms of the Creative Commons Attribution 4.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI.

Acknowledgement

In the preparation of this manuscript, the following people contributed project leadership, project design, proposal writing, and major contributions to telescope observations (>400 spectra each): Lauren M. Weiss (2013–2023), Howard T. Isaacson (2013–2023), and Geoffrey W. Marcy (2013–2015). L.M.W. developed the KGPS algorithm, conducted the analysis, generated all figures, and wrote the manuscript, with H.T.I. contributing substantially to project management, sample selection, and manuscript preparation. The following people made major contributions to database maintenance, characterization of stellar properties, data reduction, observing logistics, and telescope observations: Andrew W. Howard, B.J. Fulton, and Erik A. Petigura. The following people wrote telescope proposals that secured the observations presented in this paper and also provided feedback on the manuscript: Eric Agol, Daniel Fabrycky, Eric B. Ford, Daniel Jontof-Hutter, Daniel Huber, Miki Nakajima, James Owen, Alan Reyes, Leslie A. Rogers, Jason Rowe, Jason Steffen, Hilke E. Schlichting, and Jason T. Wright. The following people collected at least 10 nights of observations at Keck Observatory: H.T.I. (851 observations over 152 nights), L.M.W. (456 observations over 122 nights), E.A.P. (174 observations over 66 nights), B.J.F. (254 observations over 59 nights), Evan Sinukoff (260 observations over 57 nights), A.W.H. (329 observations over 56 nights), Lea Hirsch (254 observations over 53 nights), Ashley Chontos (103 observations over 48 nights), G.W.M. (456 observations over 45 nights), Steven Giacalone (113 observations over 45 nights), Joseph M. Akana Murphy (76 observations over 42 nights), Judah van Zandt (83 observations over 42 nights), Corey Beard (88 observations over 37 nights), Malena Rice (81 observations over 37 nights), Molly Kosiarek (83 observations over 35 nights), Sarah Blunt (75 observations over 34 nights), Fei Dai (59 observations over 30 nights), Jack Lubin (61 observations over 29 nights), Paul Dalba (74 observations over 28 nights), Ryan Rubenzahl (67 observations over 27 nights), Alex Polanski (41 observations over 26 nights), Casey Brinkman (53 observations over 23 nights), Aida Behmard (50 observations over 23 nights), Teo Mocnik (58 observations over 20 nights), Michelle Hill (39 observations over 19 nights), Lee Rosenthal (42 observations over 18 nights), Dakotah Tyler (37 observations over 16 nights), Emma Turtelboom (41 observations over 16 nights), Daria Pidhorodetska (25 observations over 13 nights), Mason MacDougall (25 observations over 13 nights), Ian Crossfield (29 observations over 12 nights), Samuel K. Grunblatt (39 observations over 12 nights), Sean M. Mills (30 observations over 11 nights), Rae J. Holcomb (30 observations over 11 nights), and Samuel Yee (16 observations over 10 nights). The following people contributed fewer than 10 nights of observations at Keck Observatory: Andrew Mayo, Ben Montet, Ji Wang, Marta Bryan, Isabel Angelo, Debra Fischer, Rebecca Jensen-Clem, Stephen Kane, Nicholas Saunders, Emma Louden, Jingwen Zhang, Jon Swift, John Brewer, David Shaw, Tabby Boyajian, Gaspar Bakos, Aaron Householder, Jonathan Giguere, Gregory Gilbert, Luke Handley, George Zhou, Dan Bayliss, Luke Bouma, Shannon Dulz, Phil Muirhead, Chas Beichman, Grant Regen, Sarah Lange, and Joel Hartman. J.T.W. and M.H. acknowledge the astronomers who declined authorship on this paper for reasons described in https://www.science.org/content/article/after-outcry-disgraced-sexual-harasser-removed-astronomy-manuscript.

This work would not have been possible without the generosity of various time-allocation committees that provided support in the form of Keck-HIRES observing time over a decade. We acknowledge support in the form of observational resources at W. M. Keck Observatory from the following institutions: NASA, the University of Hawai'i, the University of California, California Institute of Technology, and the University of Notre Dame. We acknowledge support from the NASA-Keck Key Strategic Mission Support program (grant No. 80NSSC19K1475), NASA Exoplanet Research Program (grant No. 80NSSC23K0269), and NASA JPL RSAs 1537000, 1607073, and 1633061.

This work was supported by a NASA-Keck PI Data Award, administered by the NASA Exoplanet Science Institute. Data presented herein were obtained at the W. M. Keck Observatory from telescope time allocated to the National Aeronautics and Space Administration through the agency's scientific partnership with the California Institute of Technology and the University of California. The Observatory was made possible by the generous financial support of the W. M. Keck Foundation. The Center for Exoplanets and Habitable Worlds and the Penn State Extraterrestrial Intelligence Center are supported by Penn State and its Eberly College of Science.

This data set made use of the NASA Exoplanet Science Institute at IPAC, which is operated by the California Institute of Technology under contract with the National Aeronautics and Space Administration. This research has made use of NASA's Astrophysics Data System Bibliographic Services. This research has made use of the SIMBAD database, operated at CDS, Strasbourg, France.

The authors wish to recognize and acknowledge the very significant cultural role and reverence that the summit of Maunakea has always had within the indigenous Hawaiian community. We are most fortunate to have the opportunity to conduct observations from this mountain.

Facilities

Kepler - , Keck:I - KECK I Telescope, TNG - Telescopio Nazionale Galileo, OHP:1.93m. -

Software References

astropy (Astropy Collaboration 201320182022), RadVel, rvsearch, kgps.

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Additional details

Created:
January 27, 2025
Modified:
January 27, 2025