CaltechAUTHORS
Published February 2021 | Version Submitted + Published
Journal Article Open

TOI-811b and TOI-852b: New Transiting Brown Dwarfs with Similar Masses and Very Different Radii and Ages from the TESS Mission

Creators

  • 1. ROR icon Harvard University
  • 2. ROR icon Harvard-Smithsonian Center for Astrophysics
  • 3. ROR icon National Science Foundation
  • 4. ROR icon University of Geneva
  • 5. ROR icon Vanderbilt University
  • 6. ROR icon Fisk University
  • 7. ROR icon University of Wisconsin–Madison
  • 8. ROR icon Princeton University
  • 9. ROR icon Space Telescope Science Institute
  • 10. ROR icon Cerro Tololo Inter-American Observatory
  • 11. ROR icon Ames Research Center
  • 12. ROR icon Goddard Space Flight Center
  • 13. ROR icon Massachusetts Institute of Technology
  • 14. ROR icon University of Louisville
  • 15. ROR icon University of North Carolina at Chapel Hill
  • 16. ROR icon NASA Exoplanet Science Institute
  • 17. ROR icon Michigan State University
  • 18. ROR icon University of Toronto

Abstract

We report the discovery of two transiting brown dwarfs (BDs), TOI-811b and TOI-852b, from NASA's Transiting Exoplanet Survey Satellite mission. These two transiting BDs have similar masses but very different radii and ages. Their host stars have similar masses, effective temperatures, and metallicities. The younger and larger transiting BD is TOI-811b at a mass of M_b = 59.9 ± 13.0M J and radius of R_b = 1.26 ± 0.06R J, and it orbits its host star in a period of P = 25.16551 ± 0.00004 days. We derive the host star's age of 93⁺⁶¹₋₂₉ Myr from an application of gyrochronology. The youth of this system, rather than external heating from its host star, is why this BD's radius is relatively large. This constraint on the youth of TOI-811b allows us to test substellar mass–radius evolutionary models at young ages where the radius of BDs changes rapidly. TOI-852b has a similar mass at M_b = 53.7 ± 1.4M J but is much older (4 or 8 Gyr, based on bimodal isochrone results of the host star) and is also smaller with a radius of R_b = 0.83 ± 0.04R_J. TOI-852b's orbital period is P = 4.94561 ± 0.00008 days. TOI-852b joins the likes of other old transiting BDs that trace out the oldest substellar mass–radius evolutionary models where contraction of the BD's radius slows and approaches a constant value. Both host stars have a mass of M⋆ = 1.32 M_⊙ ± 0.05 and differ in their radii, T_(eff_, and [Fe/H], with TOI-811 having R⋆ = 1.27 ± 0.09 R_⊙, T_(eff) = 6107 ± 77 K, and [Fe/H] = + 0.40 ± 0.09 and TOI-852 having R⋆ = 1.71 ± 0.04 R_⊙, T_(eff) = 5768 ± 84 K, and [Fe/H] = + 0.33 ± 0.09. We take this opportunity to examine how TOI-811b and TOI-852b serve as test points for young and old substellar isochrones, respectively.

Additional Information

© 2021 The American Astronomical Society. Received 2020 September 28; revised 2020 December 4; accepted 2020 December 16; published 2021 January 29. Funding for the TESS mission is provided by NASA's Science Mission directorate. This paper includes data collected by the TESS mission, which are publicly available from the Mikulski Archive for Space Telescopes (MAST). 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. 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. Funding for this work is provided by the National Science Foundation Graduate Research Fellowship Program Fellowship (GRFP). T.W.C. acknowledges the efforts of the members of the TESS Follow-up Program and the Science Processing Operations Center in making the TESS data readily accessible for the analysis in this work. T.W.C. also thanks Adam Kraus and Elisabeth Newton for contributing discussions. The MEarth Team gratefully acknowledges funding from the David and Lucile Packard Fellowship for Science and Engineering (awarded to D.C.). This material is based on work supported by the National Science Foundation under grants AST-0807690, AST-1109468, AST-1004488 (Alan T. Waterman Award), and AST-1616624 and on work supported by the National Aeronautics and Space Administration under grant No. 80NSSC18K0476 issued through the XRP Program. This work is made possible by a grant from the John Templeton Foundation. The opinions expressed in this publication are those of the authors and do not necessarily reflect the views of the John Templeton Foundation. This work makes use of observations from the LCOGT network. The authors thank the reviewer for the timely feedback and thoughtful comments. Facilities: TESS - , Las Cumbres Observatory Global Telescope (LCOGT) - , SuperWASP - , SOAR (HRCam) - , Gaia - , FLWO:1.5 m (TRES) - , CTIO:1.5 m (CHIRON) - , Euler:1.2 m (CORALIE) - , WISE (infrared) - , CTIO:2MASS (optical - , infrared) - , MEarth (Optical). - Software: EXOFASTv2 (Eastman et al. 2019), SPC (Buchhave et al. 2012), LCO BANZAI (Collins et al. 2017), AstroImageJ (Collins et al. 2017).

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Published - Carmichael_2021_AJ_161_97.pdf

Submitted - 2009.13515.pdf

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Additional details

Identifiers

Eprint ID
107834
Resolver ID
CaltechAUTHORS:20210201-121442659

Related works

Describes
https://arxiv.org/abs/2009.13515 (URL)

Funding

Gaia Multilateral Agreement
NSF Graduate Research Fellowship
David and Lucile Packard Foundation
NSF
AST-0807690
NSF
AST-1109468
NSF
AST-1004488
NSF
AST-1616624
NASA
80NSSC18K0476
John Templeton Foundation

Dates

Created
2021-02-01
Created from EPrint's datestamp field
Updated
2021-11-16
Created from EPrint's last_modified field

Caltech Custom Metadata

Caltech groups
Infrared Processing and Analysis Center (IPAC)