Hundreds of TESS Exoplanets Might Be Larger than We Thought

The radius of a planet is a fundamental parameter that probes its composition and habitability. Precise radius measurements are typically derived from the fraction of starlight blocked when a planet transits its host star. The wide-field Transiting Exoplanet Survey Satellite (TESS) has discovered hu...

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Main Authors: Te Han, Paul Robertson, Timothy D. Brandt, Shubham Kanodia, Caleb Cañas, Avi Shporer, George Ricker, Corey Beard
Format: Article
Language:English
Published: IOP Publishing 2025-01-01
Series:The Astrophysical Journal Letters
Subjects:
Online Access:https://doi.org/10.3847/2041-8213/ade794
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author Te Han
Paul Robertson
Timothy D. Brandt
Shubham Kanodia
Caleb Cañas
Avi Shporer
George Ricker
Corey Beard
author_facet Te Han
Paul Robertson
Timothy D. Brandt
Shubham Kanodia
Caleb Cañas
Avi Shporer
George Ricker
Corey Beard
author_sort Te Han
collection DOAJ
description The radius of a planet is a fundamental parameter that probes its composition and habitability. Precise radius measurements are typically derived from the fraction of starlight blocked when a planet transits its host star. The wide-field Transiting Exoplanet Survey Satellite (TESS) has discovered hundreds of new exoplanets, but its low angular resolution means that the light from a star hosting a transiting exoplanet can be blended with the light from background stars. If not fully corrected, this extra light can dilute the transit signal and result in a smaller measured planet radius. In a study of hundreds of TESS planet discoveries using deblended light curves from our validated methodology, we show that systematically incorrect planet radii are common in the literature: studies using various public TESS photometry pipelines have underestimated the planet radius by a weighted median of 6.1% ± 0.3%, leading to a ∼20% overestimation of planet density. The widespread presence of these biases in the literature has profoundly shaped—and potentially misrepresented—our understanding of the exoplanet population. Addressing these biases will refine the exoplanet mass–radius relation, reshape our understanding of exoplanet atmospheric and bulk composition, and potentially inform prevailing planet formation theories.
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spelling doaj-art-75d054eaed42428a9f974fc30cf2e2f12025-08-20T03:31:46ZengIOP PublishingThe Astrophysical Journal Letters2041-82052025-01-019881L410.3847/2041-8213/ade794Hundreds of TESS Exoplanets Might Be Larger than We ThoughtTe Han0https://orcid.org/0000-0002-7127-7643Paul Robertson1https://orcid.org/0000-0003-0149-9678Timothy D. Brandt2https://orcid.org/0000-0003-2630-8073Shubham Kanodia3https://orcid.org/0000-0001-8401-4300Caleb Cañas4https://orcid.org/0000-0003-4835-0619Avi Shporer5https://orcid.org/0000-0002-1836-3120George Ricker6https://orcid.org/0000-0003-2058-6662Corey Beard7https://orcid.org/0000-0001-7708-2364Department of Physics & Astronomy, The University of California , Irvine, CA 92697, USA ; tehanhunter@gmail.comDepartment of Physics & Astronomy, The University of California , Irvine, CA 92697, USA ; tehanhunter@gmail.comSpace Telescope Science Institute , 3700 San Martin Dr, Baltimore, MD 21218, USAEarth and Planets Laboratory, Carnegie Institution for Science , 5241 Broad Branch Road, NW, Washington, DC 20015, USANASA Postdoctoral Fellow; NASA Goddard Space Flight Center , 8800 Greenbelt Road, Greenbelt, MD 20771, USADepartment of Physics and Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology , Cambridge, MA 02139, USADepartment of Physics and Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology , Cambridge, MA 02139, USADepartment of Physics & Astronomy, The University of California , Irvine, CA 92697, USA ; tehanhunter@gmail.com; NASA FINESST FellowThe radius of a planet is a fundamental parameter that probes its composition and habitability. Precise radius measurements are typically derived from the fraction of starlight blocked when a planet transits its host star. The wide-field Transiting Exoplanet Survey Satellite (TESS) has discovered hundreds of new exoplanets, but its low angular resolution means that the light from a star hosting a transiting exoplanet can be blended with the light from background stars. If not fully corrected, this extra light can dilute the transit signal and result in a smaller measured planet radius. In a study of hundreds of TESS planet discoveries using deblended light curves from our validated methodology, we show that systematically incorrect planet radii are common in the literature: studies using various public TESS photometry pipelines have underestimated the planet radius by a weighted median of 6.1% ± 0.3%, leading to a ∼20% overestimation of planet density. The widespread presence of these biases in the literature has profoundly shaped—and potentially misrepresented—our understanding of the exoplanet population. Addressing these biases will refine the exoplanet mass–radius relation, reshape our understanding of exoplanet atmospheric and bulk composition, and potentially inform prevailing planet formation theories.https://doi.org/10.3847/2041-8213/ade794ExoplanetsLight curvesTransits
spellingShingle Te Han
Paul Robertson
Timothy D. Brandt
Shubham Kanodia
Caleb Cañas
Avi Shporer
George Ricker
Corey Beard
Hundreds of TESS Exoplanets Might Be Larger than We Thought
The Astrophysical Journal Letters
Exoplanets
Light curves
Transits
title Hundreds of TESS Exoplanets Might Be Larger than We Thought
title_full Hundreds of TESS Exoplanets Might Be Larger than We Thought
title_fullStr Hundreds of TESS Exoplanets Might Be Larger than We Thought
title_full_unstemmed Hundreds of TESS Exoplanets Might Be Larger than We Thought
title_short Hundreds of TESS Exoplanets Might Be Larger than We Thought
title_sort hundreds of tess exoplanets might be larger than we thought
topic Exoplanets
Light curves
Transits
url https://doi.org/10.3847/2041-8213/ade794
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