CaltechAUTHORS
Published June 2022 | Version Accepted Version + Published
Journal Article Open

A Close-in Puffy Neptune with Hidden Friends: The Enigma of TOI 620

Creators

  • 1. ROR icon George Mason University
  • 2. ROR icon Instituto de Astrofísica de Andalucía
  • 3. ROR icon University of Hawaii at Manoa
  • 4. ROR icon University of California, Irvine
  • 5. ROR icon Institut de Planétologie et d'Astrophysique de Grenoble
  • 6. ROR icon University of Geneva
  • 7. ROR icon Jet Propulsion Lab
  • 8. ROR icon Infrared Processing and Analysis Center
  • 9. ROR icon Instituto de Astrofísica de Canarias
  • 10. ROR icon University of La Laguna
  • 11. ROR icon Vanderbilt University
  • 12. ROR icon Harvard-Smithsonian Center for Astrophysics
  • 13. ROR icon University of Montreal
  • 14. ROR icon Ames Research Center
  • 15. ROR icon Goddard Space Flight Center
  • 16. ROR icon Space Telescope Science Institute
  • 17. ROR icon Massachusetts Institute of Technology
  • 18. ROR icon University of Florida
  • 19. ROR icon University of Chicago
  • 20. ROR icon NASA Exoplanet Science Institute
  • 21. ROR icon University of Warwick
  • 22. ROR icon University of Naples Federico II
  • 23. ROR icon Pennsylvania State University
  • 24. ROR icon University of Kansas
  • 25. ROR icon University of California, Berkeley
  • 26. ROR icon German Aerospace Center
  • 27. ROR icon University of Tokyo
  • 28. ROR icon Carnegie Institution for Science
  • 29. ROR icon Mississippi State University
  • 30. ROR icon University of California, Santa Cruz
  • 31. ROR icon California Institute of Technology
  • 32. ROR icon United States Naval Observatory
  • 33. ROR icon Astrobiology Center
  • 34. ROR icon Macquarie University
  • 35. ROR icon University of Cambridge
  • 36. ROR icon Princeton University
  • 37. ROR icon Heidelberg University
  • 38. ROR icon Carleton College
  • 39. ROR icon Tsinghua University
  • 40. ROR icon University of Göttingen
  • 41. ROR icon Louisiana State University

Abstract

We present the validation of a transiting low-density exoplanet orbiting the M2.5 dwarf TOI 620 discovered by the NASA Transiting Exoplanet Survey Satellite (TESS) mission. We utilize photometric data from both TESS and ground-based follow-up observations to validate the ephemerides of the 5.09 day transiting signal and vet false-positive scenarios. High-contrast imaging data are used to resolve the stellar host and exclude stellar companions at separations ≳0.″2. We obtain follow-up spectroscopy and corresponding precise radial velocities (RVs) with multiple precision radial velocity (PRV) spectrographs to confirm the planetary nature of the transiting exoplanet. We calculate a 5σ upper limit of Mₚ < 7.1M_⊕ and ρₚ < 0.74 g cm⁻³, and we identify a nontransiting 17.7 day candidate. We also find evidence for a substellar (1–20 Mⱼ) companion with a projected separation ≲20 au from a combined analysis of Gaia, adaptive optics imaging, and RVs. With the discovery of this outer companion, we carry out a detailed exploration of the possibilities that TOI 620 b might instead be a circum-secondary planet or a pair of eclipsing binary stars orbiting the host in a hierarchical triple system. We find, under scrutiny, that we can exclude both of these scenarios from the multiwavelength transit photometry, thus validating TOI 620 b as a low-density exoplanet transiting the central star in this system. The low density of TOI 620 b makes it one of the most amenable exoplanets for atmospheric characterization, such as with the James Webb Space Telescope and Ariel, validated or confirmed by the TESS mission to date.

Additional Information

© 2022. 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. Received 2021 October 23; revised 2022 March 11; accepted 2022 April 6; published 2022 May 16. M.A.R. and P.P.P. acknowledge support from NASA (Exoplanet Research Program Award #80NSSC20K0251, TESS Cycle 3 Guest Investigator Program Award #80NSSC21K0349, JPL Research and Technology Development, and Keck Observatory Data Analysis) and the NSF (Astronomy and Astrophysics grant Nos. 1716202 and 2006517), and the Mt Cuba Astronomical Foundation. R.L. acknowledges financial support from the Spanish Ministerio de Ciencia e Innovación, through project PID2019-109522GB-C52, and the Centre of Excellence "Severo Ochoa" award to the Instituto de Astrofísica de Andalucía (SEV-2017-0709). This work is partly supported by JSPS KAKENHI grant No. P17H04574, JP18H05439, JP20K14518, JP21K13975, JST CREST grant No. JPMJCR1761, and the Astrobiology Center of National Institutes of Natural Sciences (NINS) (grant Nos. AB022006, AB031010, AB031014). This work is partly financed by the Spanish Ministry of Economics and Competitiveness through grant No. PGC2018-098153-B-C31. The development of the MAROON-X spectrograph was funded by the David and Lucile Packard Foundation, the Heising-Simons Foundation, the Gemini Observatory, and the University of Chicago. We thank the staff of the Gemini Observatory for their assistance with the commissioning and operation of the instrument. The MAROON-X observing program is supported by NSF grant No. 2108465. This work was enabled by observations made from the Gemini North telescope, located within the Maunakea Science Reserve and adjacent to the summit of Maunakea. We are grateful for the privilege of observing the universe from a place that is unique in both its astronomical quality and its cultural significance. Some of the observations in the paper made use of the High-Resolution Imaging instrument Zorro obtained under Gemini LLP Proposal Number GN/S-2021A-LP-105. Zorro was funded by the NASA Exoplanet Exploration Program and built at the NASA Ames Research Center by Steve B. Howell, Nic Scott, Elliott P. Horch, and Emmett Quigley. Zorro was mounted on the Gemini South telescope of the international Gemini Observatory, a program of NSF's OIR Lab, which is managed by the Association of Universities for Research in Astronomy (AURA) under a cooperative agreement with the National Science Foundation. on behalf of the Gemini partnership: the National Science Foundation (United States), National Research Council (Canada), Agencia Nacional de Investigación y Desarrollo (Chile), Ministerio de Ciencia, Tecnología e Innovación (Argentina), Ministério da Ciência, Tecnologia, Inovações e Comunicações (Brazil), and Korea Astronomy and Space Science Institute (Republic of Korea). V.K. gratefully acknowledges support from NASA via grant No. NNX17AF81G. Based on data collected under the NGTS project at the ESO La Silla Paranal Observatory. The NGTS facility is operated by the consortium institutes with support from the UK Science and Technology Facilities Council (STFC) projects ST/M001962/1 and ST/S002642/1. This work has made use of data from the European Space Agency (ESA) mission Gaia (https://www.cosmos.esa.int/gaia), processed by the Gaia Data Processing and Analysis Consortium (DPAC, https://www.cosmos.esa.int/web/gaia/dpac/consortium). Funding for the DPAC has been provided by national institutions, in particular the institutions participating in the Gaia Multilateral Agreement. M.L. acknowledges support from the Swiss National Science Foundation under grant No. PCEFP2_194576. The contribution of M.L. has been carried out within the framework of the NCCR PlanetS supported by the Swiss National Science Foundation. C.I.C. acknowledges support by NASA Headquarters under the NASA Earth and Space Science Fellowship Program through grant No. 80NSSC18K1114. NEID is funded by NASA/JPL under contract 1547612. Observations in this paper made use of the NN-EXPLORE Exoplanet and Stellar Speckle Imager (NESSI). NESSI was funded by the NASA Exoplanet Exploration Program and the NASA Ames Research Center. NESSI was built at the Ames Research Center by Steve B. Howell, Nic Scott, Elliott P. Horch, and Emmett Quigley. This paper is based on observations obtained from the Las Campanas Remote Observatory, which is a partnership between Carnegie Observatories, The Astro-Physics Corporation, Howard Hedlund, Michael Long, Dave Jurasevich, and SSC Observatories. We acknowledge support from NSF grant Nos. AST-190950 and 1910954. This article is based on observations made with the MuSCAT2 instrument, developed by ABC, at Telescopio Carlos Sánchez, operated on the island of Tenerife by the IAC in the Spanish Observatorio del Teide. This material is based upon work supported by the National Science Foundation Graduate Research Fellowship under grant No. DGE 1746045. We acknowledge the use of public TESS data from pipelines at the TESS Science Office and at the TESS Science Processing Operations Center. Resources supporting this work were provided by the NASA High-End Computing (HEC) Program through the NASA Advanced Supercomputing (NAS) Division at Ames Research Center for the production of the SPOC data products. Based on data collected under the ExTrA project at the ESO La Silla Paranal Observatory. ExTrA is a project of Institut de Planétologie et d'Astrophysique de Grenoble (IPAG/CNRS/UGA), funded by the European Research Council under the ERC Grant Agreement No. 337591-ExTrA. This work has been supported by a grant from Labex OSUG@2020 (Investissements d'avenir—ANR10 LABX56). Facilities: NASA IRTF - , Calar Alto Observatory - , Gemini North - , Gemini South - , Fred L. Whipple Observatory - , TESS - , ESO La Silla Paranal Observatory - , Las Cumbres Observatory - , Teide Observatory - , Lick Observatory - , WIYN Observatory - . Software: Python: pychell (Cale et al. 2019), EDI-Vetter Unplugged (Zink et al. 2020), DAVE (Kostov et al. 2019), tpfplotter (Aller et al. 2020), emcee (Foreman-Mackey et al. 2013), NumPy (Harris et al. 2020), SciPy (Virtanen et al. 2020), Matplotlib (Hunter 2007), AstroPy (Robitaille et al. 2013), corner (Foreman-Mackey et al. 2020), barycorrpy (Kanodia & Wright 2018), Numba (Lam et al. 2015), PyTransit (Parviainen 2015), serval (Zechmeister et al. 2018), IDL: EXOFASTv2 (Eastman et al.2013).

Attached Files

Published - Reefe_2022_AJ_163_269.pdf

Accepted Version - 2204.03108.pdf

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Additional details

Identifiers

Eprint ID
115091
Resolver ID
CaltechAUTHORS:20220608-849600000

Related works

Describes
https://arxiv.org/abs/2204.03108 (URL)

Funding

NASA
80NSSC20K0251
NASA
80NSSC21K0349
JPL Research and Technology Development Fund
NSF
AST-1716202
NSF
AST-2006517
Mt. Cuba Astronomical Foundation
Ministerio de Ciencia, Innovación y Universidades (MCIU)
PID2019-109522GB-C52
Severo Ochoa
SEV-2017-0709
Japan Society for the Promotion of Science (JSPS)
P17H04574
Japan Society for the Promotion of Science (JSPS)
JP18H05439
Japan Society for the Promotion of Science (JSPS)
JP20K14518
Japan Society for the Promotion of Science (JSPS)
JP21K13975
Japan Science and Technology Agency
JPMJCR1761
National Institutes of Natural Sciences of Japan
AB022006
National Institutes of Natural Sciences of Japan
AB031010
National Institutes of Natural Sciences of Japan
AB031014
Ministerio de Economía, Industria y Competitividad (MINECO)
PGC2018-098153-B-C31
NSF
AST-2108465
Gemini Partnership
NASA
NNX17AF81G
Science and Technology Facilities Council (STFC)
ST/M001962/1
Science and Technology Facilities Council (STFC)
ST/S002642/1
Gaia Multilateral Agreement
Swiss National Science Foundation (SNSF)
PCEFP2_194576
NASA Earth and Space Science Fellowship
80NSSC18K1114
JPL
1547612
NSF
AST-190950
NSF
AST-1910954
NSF Graduate Research Fellowship
DGE-1746045
Agence Nationale pour la Recherche (ANR)
ANR10 LABX56

Dates

Created
2022-06-08
Created from EPrint's datestamp field
Updated
2022-06-08
Created from EPrint's last_modified field

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Caltech groups
Infrared Processing and Analysis Center (IPAC)