Michelle Hill
Postdoctoral Scholar, Earth and Planetary Sciences
Web page: http://planethuntress.com
Bio
Michelle's work addresses a fundamental question in exoplanet habitability: determining the minimum planetary size required to maintain an atmosphere, a critical prerequisite for life as we know it. She found that stagnant lid (no plate tectonics) planets Earth sized and below orbiting in the habitable zone (HZ) of a Sun-like star need to be ≥ 0.8 Earth radii to maintain their atmosphere past 1 billion years. As a Stanford Science Fellow, Michelle will advance her research and expand her planetary habitability models to look at how tectonic regime, initial volatile content, stellar type, tidal locking and tidal heating effect the results of whether a planet smaller than Earth can hold onto it's atmosphere. Her faculty host is Laura Schaefer, Assistant Professor in the department of Earth and Planetary Sciences.
Michelle also detects and refines the masses and orbits of exoplanets using a combination of radial velocity (RV), transit and astrometry. She is currently observing 10 known planet systems that have shown indications of additional planets in orbit in order to detect the long period outer companions. These observations have lead to the discovery of 3 planets so far.
Michelle recently completed her PhD in Earth and planetary sciences at the University of California, Riverside, where she developed research on exoplanet habitability while supported by the NASA FINESST award. She lead a catalog paper on the demographics of all the known planets in HZ of their star where she found evidence of the sub-Saturn valley in the HZ. During this time she was also a member of the TESS-Keck Survey (TKS) team that conducted RV followup of TESS Objects of Interest (TOIs) and she lead the discovery paper of TOI-1386 b and c.
Michelle completed her post bachelor honours in astrophysics at University of Southern Queensland, Australia. Here Michelle worked on the occurrence rates of giant exoplanets in the habitable zone of their star and found that while giant planets are less likely to be found in the habitable zone than terrestrial planets, if each giant planet is host to more than one moon then exomoons could be more numerous than terrestrial planets in the habitable zone of their star. This work has direct implications for the fraction of stars in the galaxy that may host habitable terrestrial worlds.
Prior to this Michelle completed her bachelors in physics at University of New England, Australia where she attended San Francisco State University during her year abroad. Here she contributed to a study of the Kepler habitable zone planets where she found that the distribution of planets within the habitable zone closely mirrored the distribution of all known planets. This discovery had major implications for the opportunities of statistical analysis of this relatively small group of habitable zone planets.
Michelle loves flying! She was a commercial pilot before returning to school to study physics. She currently holds an Australian ATPL with plans to (one day!) convert this to an FAA APT.
Honors & Awards
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Stanford Science Fellow, Stanford University (2025 - 2028)
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FINESST Fellow, NASA (2021 - 2025)
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First Class Honours, University of Southern Queensland (2018)
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Vice Chancellor Honour Roll, University of New England (2015 - 2016)
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Dean’s List, San Francisco State University (2015)
Professional Education
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Bachelor of Science, University Of New England (2017)
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Doctor of Science, University of California Riverside (2025)
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PhD, University of California, Riverside, Earth & Planetary Science (2025)
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Bachelor of Science. Honors, University of Southern Queensland, Physics (2018)
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Bachelor of Science, University of New England, Physics (2017)
All Publications
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No Giant Planets in the Eta Cassiopeiae System: Dynamical Implications of a Wide Binary Companion
ASTRONOMICAL JOURNAL
2025; 170 (5)
View details for DOI 10.3847/1538-3881/ae089f
View details for Web of Science ID 001594180900001
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Planet Masses, Radii, and Orbits from NASA's K2 Mission
ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES
2025; 278 (2)
View details for DOI 10.3847/1538-4365/adc5e4
View details for Web of Science ID 001504278800001
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The TESS-Keck Survey. XXIV. Outer Giants May Be More Prevalent in the Presence of Inner Small Planets
ASTRONOMICAL JOURNAL
2025; 169 (5)
View details for DOI 10.3847/1538-3881/adbbed
View details for Web of Science ID 001458437300001
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The California Legacy Survey. V. Chromospheric Activity Cycles in Main-sequence Stars
ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES
2024; 274 (2)
View details for DOI 10.3847/1538-4365/ad676c
View details for Web of Science ID 001322174400001
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The TESS-Keck Survey. XXII. A Sub-Neptune Orbiting TOI-1437
ASTRONOMICAL JOURNAL
2024; 168 (3)
View details for DOI 10.3847/1538-3881/ad6901
View details for Web of Science ID 001307382300001
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The TESS-Keck Survey. XX. 15 New TESS Planets and a Uniform RV Analysis of All Survey Targets
ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES
2024; 272 (2)
View details for DOI 10.3847/1538-4365/ad4484
View details for Web of Science ID 001229872100001
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The TESS-Keck Survey. VII. A Superdense Sub-Neptune Orbiting TOI-1824
ASTRONOMICAL JOURNAL
2024; 167 (6)
View details for DOI 10.3847/1538-3881/ad34d9
View details for Web of Science ID 001229868300001
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The TESS-Keck Survey. XVIII. A Sub-Neptune and Spurious Long-period Signal in the TOI-1751 System
ASTRONOMICAL JOURNAL
2024; 167 (5)
View details for DOI 10.3847/1538-3881/ad29ee
View details for Web of Science ID 001196732200001
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The TESS-Keck Survey. XIX. A Warm Transiting Sub-Saturn-mass Planet and a Nontransiting Saturn-mass Planet Orbiting a Solar Analog
ASTRONOMICAL JOURNAL
2024; 167 (4)
View details for DOI 10.3847/1538-3881/ad2765
View details for Web of Science ID 001184123300001
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The TESS-Keck Survey. XII. A Dense 1.8 <i>R</i> <sub>⊕</sub> Ultra-short-period Planet Possibly Clinging to a High-mean-molecular-weight Atmosphere after the First Gigayear
ASTRONOMICAL JOURNAL
2024; 167 (4)
View details for DOI 10.3847/1538-3881/ad28bb
View details for Web of Science ID 001185113200001
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The TESS-Keck Survey. XVII. Precise Mass Measurements in a Young, High-multiplicity Transiting Planet System Using Radial Velocities and Transit Timing Variations
ASTRONOMICAL JOURNAL
2024; 167 (2)
View details for DOI 10.3847/1538-3881/ad1330
View details for Web of Science ID 001151994800001
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The Kepler Giant Planet Search. I. A Decade of Kepler Planet-host Radial Velocities from W. M. Keck Observatory
ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES
2024; 270 (1)
View details for DOI 10.3847/1538-4365/ad0cab
View details for Web of Science ID 001132045900001
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The TESS-Keck Survey. XVI. Mass Measurements for 12 Planets in Eight Systems
ASTRONOMICAL JOURNAL
2023; 166 (4)
View details for DOI 10.3847/1538-3881/ace2ca
View details for Web of Science ID 001062303400001
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The TESS-Keck Survey. XV. Precise Properties of 108 TESS Planets and Their Host Stars
ASTRONOMICAL JOURNAL
2023; 166 (1)
View details for DOI 10.3847/1538-3881/acd557
View details for Web of Science ID 001017145500001
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Revised Properties and Dynamical History for the HD 17156 System
ASTRONOMICAL JOURNAL
2023; 165 (6)
View details for DOI 10.3847/1538-3881/acd17a
View details for Web of Science ID 000994586700001
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Revisiting the Red Giant Branch Hosts KOI-3886 and <i>ι</i> Draconis. Detailed Asteroseismic Modeling and Consolidated Stellar Parameters
ASTRONOMICAL JOURNAL
2023; 165 (5)
View details for DOI 10.3847/1538-3881/acc9c1
View details for Web of Science ID 000977273700001
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The Demographics of Terrestrial Planets in the Venus Zone
ASTRONOMICAL JOURNAL
2023; 165 (4)
View details for DOI 10.3847/1538-3881/acbfaf
View details for Web of Science ID 000954219200001
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TESS-Keck Survey. XIV. Two Giant Exoplanets from the Distant Giants Survey
ASTRONOMICAL JOURNAL
2023; 165 (2)
View details for DOI 10.3847/1538-3881/aca6ef
View details for Web of Science ID 000922956300001
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TOI-1136 is a Young, Coplanar, Aligned Planetary System in a Pristine Resonant Chain
ASTRONOMICAL JOURNAL
2023; 165 (2)
View details for DOI 10.3847/1538-3881/aca327
View details for Web of Science ID 000922177100001
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A Catalog of Habitable Zone Exoplanets
ASTRONOMICAL JOURNAL
2023; 165 (2)
View details for DOI 10.3847/1538-3881/aca1c0
View details for Web of Science ID 000907932900001
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TOI 560: Two Transiting Planets Orbiting a K Dwarf Validated with iSHELL, PFS, and HIRES RVs
ASTRONOMICAL JOURNAL
2023; 165 (1)
View details for DOI 10.3847/1538-3881/ac9834
View details for Web of Science ID 000928225500001
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GJ 1252b: A Hot Terrestrial Super-Earth with No Atmosphere
ASTROPHYSICAL JOURNAL LETTERS
2022; 937 (1)
View details for DOI 10.3847/2041-8213/ac886b
View details for Web of Science ID 000860813100001
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The TESS-Keck Survey: * Science Goals and Target Selection
ASTRONOMICAL JOURNAL
2022; 163 (6)
View details for DOI 10.3847/1538-3881/ac6266
View details for Web of Science ID 000802774900001
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An Aligned Orbit for the Young Planet V1298 Tau b
ASTRONOMICAL JOURNAL
2022; 163 (6)
View details for DOI 10.3847/1538-3881/ac6271
View details for Web of Science ID 000790525800001
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The TESS-Keck Survey. XI. Mass Measurements for Four Transiting Sub-Neptunes Orbiting K Dwarf TOI-1246
ASTRONOMICAL JOURNAL
2022; 163 (6)
View details for DOI 10.3847/1538-3881/ac69e5
View details for Web of Science ID 000800004500001
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A Second Planet Transiting LTT 1445A and a Determination of the Masses of Both Worlds
ASTRONOMICAL JOURNAL
2022; 163 (4)
View details for DOI 10.3847/1538-3881/ac50a9
View details for Web of Science ID 000768522900001
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HD 207897 b: A dense sub-Neptune transiting a nearby and bright K-type star
ASTRONOMY & ASTROPHYSICS
2022; 658
View details for DOI 10.1051/0004-6361/202141429
View details for Web of Science ID 000757538000010
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The TESS-Keck Survey. VIII. Confirmation of a Transiting Giant Planet on an Eccentric 261 Day Orbit with the Automated Planet Finder Telescope*
ASTRONOMICAL JOURNAL
2022; 163 (2)
View details for DOI 10.3847/1538-3881/ac415b
View details for Web of Science ID 000742194700001
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Orbital Dynamics and the Evolution of Planetary Habitability in the AU Mic System
ASTRONOMICAL JOURNAL
2022; 163 (1)
View details for DOI 10.3847/1538-3881/ac366b
View details for Web of Science ID 000731168400001
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Constraining the Orbit and Mass of epsilon Eridani b with Radial Velocities, Hipparcos IAD-Gaia DR2 Astrometry, and Multiepoch Vortex Coronagraphy Upper Limits
ASTRONOMICAL JOURNAL
2021; 162 (5)
View details for DOI 10.3847/1538-3881/ac134a
View details for Web of Science ID 000704143900001
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Asteroseismology of iota Draconis and Discovery of an Additional Long-period Companion
ASTRONOMICAL JOURNAL
2021; 162 (5)
View details for DOI 10.3847/1538-3881/ac1b31
View details for Web of Science ID 000709977300001
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TESS-Keck Survey. V. Twin Sub-Neptunes Transiting the Nearby G Star HD 63935
ASTRONOMICAL JOURNAL
2021; 162 (5)
View details for DOI 10.3847/1538-3881/ac18cb
View details for Web of Science ID 000711179800001
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The TESS-Keck Survey. II. An Ultra-short-period Rocky Planet and Its Siblings Transiting the Galactic Thick-disk Star TOI-561
ASTRONOMICAL JOURNAL
2021; 161 (2)
View details for DOI 10.3847/1538-3881/abd409
View details for Web of Science ID 000606991800001
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Physical Parameters of the Multiplanet Systems HD 106315 and GJ 9827*dagger
ASTRONOMICAL JOURNAL
2021; 161 (1)
View details for DOI 10.3847/1538-3881/abca39
View details for Web of Science ID 000604026600001
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The TESS-Keck Survey. III. A Stellar Obliquity Measurement of TOI-1726 c
ASTRONOMICAL JOURNAL
2020; 160 (4)
View details for DOI 10.3847/1538-3881/abb3bd
View details for Web of Science ID 000576524700001
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A Volatile-poor Formation of LHS 3844b Based on Its Lack of Significant Atmosphere
PLANETARY SCIENCE JOURNAL
2020; 1 (2)
View details for DOI 10.3847/PSJ/abaab5
View details for Web of Science ID 000913030300001
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The TESS-Keck Survey. I. A Warm Sub-Saturn-mass Planet and a Caution about Stray Light in TESS Cameras
ASTRONOMICAL JOURNAL
2020; 159 (5)
View details for DOI 10.3847/1538-3881/ab84e3
View details for Web of Science ID 000531277600001
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Orbital Refinement and Stellar Properties for the HD 9446, HD 43691, and HD 179079 Planetary Systems
ASTRONOMICAL JOURNAL
2020; 159 (5)
View details for DOI 10.3847/1538-3881/ab7d33
View details for Web of Science ID 000525676000001
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The Dark Planets of the WASP-47 Planetary System
ASTRONOMICAL JOURNAL
2020; 159 (4)
View details for DOI 10.3847/1538-3881/ab7818
View details for Web of Science ID 000522908100001
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Exploring <i>Kepler</i> Giant Planets in the Habitable Zone
ASTROPHYSICAL JOURNAL
2018; 860 (1)
View details for DOI 10.3847/1538-4357/aac384
View details for Web of Science ID 000435199200001
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A CATALOG OF <i>KEPLER</i> HABITABLE ZONE EXOPLANET CANDIDATES
ASTROPHYSICAL JOURNAL
2016; 830 (1)
View details for DOI 10.3847/0004-637X/830/1/1
View details for Web of Science ID 000385655400001
https://orcid.org/0000-0002-0139-4756