The Astronomical Journal (Jan 2024)
TOI-2015 b: A Warm Neptune with Transit Timing Variations Orbiting an Active Mid-type M Dwarf
- Sinclaire E. Jones,
- Guđmundur Stefánsson,
- Kento Masuda,
- Jessica E. Libby-Roberts,
- Cristilyn N. Gardner,
- Rae Holcomb,
- Corey Beard,
- Paul Robertson,
- Caleb I. Cañas,
- Suvrath Mahadevan,
- Shubham Kanodia,
- Andrea S. J. Lin,
- Henry A. Kobulnicky,
- Brock A. Parker,
- Chad F. Bender,
- William D. Cochran,
- Scott A. Diddams,
- Rachel B. Fernandes,
- Arvind F. Gupta,
- Samuel Halverson,
- Suzanne L. Hawley,
- Fred R. Hearty,
- Leslie Hebb,
- Adam Kowalski,
- Jack Lubin,
- Andrew Monson,
- Joe P. Ninan,
- Lawrence Ramsey,
- Arpita Roy,
- Christian Schwab,
- Ryan C. Terrien,
- John Wisniewski
Affiliations
- Sinclaire E. Jones
- ORCiD
- Department of Astronomy, The Ohio State University , 4055 McPherson Laboratory, Columbus, OH 43210, USA; Department of Astrophysical Sciences, Princeton University , 4 Ivy Lane, Princeton, NJ 08540, USA
- Guđmundur Stefánsson
- ORCiD
- Department of Astrophysical Sciences, Princeton University , 4 Ivy Lane, Princeton, NJ 08540, USA; Anton Pannekoek Institute for Astronomy, University of Amsterdam , Science Park 904, 1098 XH Amsterdam, The Netherlands
- Kento Masuda
- ORCiD
- Department of Earth and Space Science, Graduate School of Science, Osaka University , 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan
- Jessica E. Libby-Roberts
- ORCiD
- Department of Astronomy & Astrophysics, 525 Davey Laboratory, The Pennsylvania State University , University Park, PA 16802, USA
- Cristilyn N. Gardner
- ORCiD
- Department of Physics & Astronomy, University of Wyoming , Laramie, WY 82070, USA
- Rae Holcomb
- ORCiD
- Department of Physics & Astronomy, The University of California , Irvine, CA 92697, USA
- Corey Beard
- ORCiD
- Department of Physics & Astronomy, The University of California , Irvine, CA 92697, USA
- Paul Robertson
- ORCiD
- Department of Physics & Astronomy, The University of California , Irvine, CA 92697, USA
- Caleb I. Cañas
- ORCiD
- NASA Goddard Space Flight Center , 8800 Greenbelt Road, Greenbelt, MD 20771, 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
- Shubham Kanodia
- ORCiD
- Earth and Planets Laboratory, Carnegie Institution for Science , 5241 Broad Branch Road, NW, Washington, DC 20015, 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
- Henry A. Kobulnicky
- ORCiD
- Department of Physics & Astronomy, University of Wyoming , Laramie, WY 82070, USA
- Brock A. Parker
- ORCiD
- Department of Physics & Astronomy, University of Wyoming , Laramie, WY 82070, USA
- Chad F. Bender
- ORCiD
- Steward Observatory, The University of Arizona , 933 N. Cherry Avenue, Tucson, AZ 85721, USA
- William D. Cochran
- ORCiD
- McDonald Observatory and Department of Astronomy, The University of Texas at Austin , 2515 Speedway, Austin, TX 78712, USA; Center for Planetary Systems Habitability, The University of Texas at Austin , 2515 Speedway, Austin, TX 78712, USA
- Scott A. Diddams
- ORCiD
- Electrical, Computer & Energy Engineering, University of Colorado Boulder , 425 UCB, Boulder, CO 80309, USA; Department of Physics, University of Colorado Boulder , 2000 Colorado Avenue, Boulder, CO 80309, USA; National Institute of Standards and Technology , 325 Broadway, Boulder, CO 80305, USA
- Rachel B. Fernandes
- 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
- Arvind F. Gupta
- 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
- Samuel Halverson
- ORCiD
- Jet Propulsion Laboratory, California Institute of Technology , 4800 Oak Grove Drive, Pasadena, CA 91109, USA
- Suzanne L. Hawley
- ORCiD
- Astronomy Department, University of Washington , Seattle, WA 98195, USA
- Fred R. Hearty
- 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
- Leslie Hebb
- ORCiD
- Department of Physics, Hobart and William Smith Colleges , 300 Pulteney Street, Geneva, NY 14456, USA; Department of Astronomy, Cornell University , 245 East Avenue, Ithaca, NY 14850, USA
- Adam Kowalski
- ORCiD
- Department of Astrophysical and Planetary Sciences, University of Colorado Boulder , 2000 Colorado Avenue, Boulder, CO 80305, USA; National Solar Observatory, University of Colorado Boulder , 3665 Discovery Drive, Boulder, CO 80303, USA; Laboratory for Atmospheric and Space Physics, University of Colorado Boulder , 3665 Discovery Drive, Boulder, CO 80303, USA
- Jack Lubin
- ORCiD
- Department of Physics & Astronomy, The University of California , Irvine, CA 92697, USA
- Andrew Monson
- ORCiD
- Steward Observatory, The University of Arizona , 933 N. Cherry Avenue, Tucson, AZ 85721, USA
- Joe P. Ninan
- ORCiD
- Department of Astronomy and Astrophysics, Tata Institute of Fundamental Research , Homi Bhabha Road, Colaba, Mumbai 400005, India
- Lawrence Ramsey
- 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
- Arpita Roy
- ORCiD
- Space Telescope Science Institute , 3700 San Martin Drive, Baltimore, MD 21218, USA; Department of Physics and Astronomy, Johns Hopkins University , 3400 N Charles Street, Baltimore, MD 21218, USA
- Christian Schwab
- ORCiD
- School of Mathematical and Physical Sciences, Macquarie University , Balaclava Road, North Ryde, NSW 2109, Australia
- Ryan C. Terrien
- ORCiD
- Carleton College , One North College Street, Northfield, MN 55057, USA
- John Wisniewski
- ORCiD
- NASA Headquarters , 300 Hidden Figures Way SW, Washington DC 20546, USA
- DOI
- https://doi.org/10.3847/1538-3881/ad55ea
- Journal volume & issue
-
Vol. 168,
no. 2
p. 93
Abstract
We report the discovery of a close-in ( P _orb = 3.349 days) warm Neptune with clear transit timing variations (TTVs) orbiting the nearby ( d = 47.3 pc) active M4 star, TOI-2015. We characterize the planet's properties using Transiting Exoplanet Survey Satellite (TESS) photometry, precise near-infrared radial velocities (RVs) with the Habitable-zone Planet Finder Spectrograph, ground-based photometry, and high-contrast imaging. A joint photometry and RV fit yields a radius ${R}_{p}={3.37}_{-0.20}^{+0.15}\ {R}_{\oplus }$ , mass ${m}_{p}={16.4}_{-4.1}^{+4.1}\ {M}_{\oplus }$ , and density ${\rho }_{p}\,={2.32}_{-0.37}^{+0.38}\ {\rm{g}}\ {\mathrm{cm}}^{-3}$ for TOI-2015 b, suggesting a likely volatile-rich planet. The young, active host star has a rotation period of P _rot = 8.7 ± 0.9 days and associated rotation-based age estimate of 1.1 ± 0.1 Gyr. Though no other transiting planets are seen in the TESS data, the system shows clear TTVs of super-period ${P}_{\sup }\approx 430\ \mathrm{days}$ and amplitude ∼100 minutes. After considering multiple likely period-ratio models, we show an outer planet candidate near a 2:1 resonance can explain the observed TTVs while offering a dynamically stable solution. However, other possible two-planet solutions—including 3:2 and 4:3 resonances—cannot be conclusively excluded without further observations. Assuming a 2:1 resonance in the joint TTV-RV modeling suggests a mass of ${m}_{b}={13.3}_{-4.5}^{+4.7}\ {M}_{\oplus }$ for TOI-2015 b and ${m}_{c}={6.8}_{-2.3}^{+3.5}\ {M}_{\oplus }$ for the outer candidate. Additional transit and RV observations will be beneficial to explicitly identify the resonance and further characterize the properties of the system.
Keywords
