I investigate the interactions between stars and their planets, with a focus on how stellar environments influence the habitability of terrestrial exoplanets. In particular, my research examines the high-energy radiation to which these planets are exposed, emphasizing ultraviolet emission and its effects on planetary atmospheres. I also model longer wavelengths to assess how stellar surface heterogeneity impacts transmission spectroscopy measurements. I am also engaged in developing mission concepts aimed at advancing our understanding of star–planet systems and their potential for habitability.
Sarah Rose Peacock
(ASSISTANT RESEARCH SCIENTIST)
| Email: | sarah.r.peacock@nasa.gov |
| Phone: | 301.286.1111 |
| Org Code: | 667 |
| Location: | Building 034 | Room E316 |
| Address: |
NASA/GSFC Mail Code 667 Greenbelt, MD 20771 |
| Employer: | UMBC Univ. of MD, Baltimore County |
Brief Bio
Current Projects
Completing Panchromatic Spectra for High Priority HWO Target Stars
I am computing full wavelength (X-ray - radio) spectra for 20 high priority target stars for the Habitable Worlds Observatory and ground-based ELTs. Ten of the stars have pre-existing X-ray and UV spectra to empirically guide the models, for the other ten, we are obtaining new HST FUV and NUV spectra (as part of Cycle 33 program 18001.)
PEGASUS: PHOENIX EUV Grid and Stellar UV Spectra
PEGASUS is a generalized grid of 1,225 synthetic spectra for M and K type stars computed with the PHOENIX stellar atmosphere code. The spectra cover wavelengths ranging from 100 A - 100 microns with resolutions of delta lambda <0.01 A across EUV - NUV wavelengths. It is accessed via a webtool that retrieves a synthetic spectrum of a specific exoplanet host star, using archival GALEX UV measurements to identify the most representative model.
https://science.data.nasa.gov/data-sites/pegasus-stellar-spectra
HWO Target Stars and Systems: High Energy Emission
Co-lead of the HWO Target Stars and Systems: High Energy Emission sub-Working Group, conducting a multi-mission archival UV and X-ray data assessment for 98 high-priority target stars to identify coverage gaps and guide future observing strategies.
Lyman-alpha Emission from K and M Dwarfs
I analyzed HST observations of intrinsic Lyman-alpha emission from high-radial-velocity K and M dwarfs. The Doppler shifts of these stars reduce interstellar medium absorption, enabling direct measurement of most of the line profile. These observations provide empirical constraints on the dependence of Lyman-alpha flux and profile morphology on stellar effective temperature, informing models of stellar UV emission and its role in shaping exoplanetary atmospheres.
Consortium on Habitability and Atmospheres of M-dwarf Planets (CHAMPS) / Strange New Worlds (SNW)
Task Lead for Star-Planet Interactions for the NASA ICAR programs: "The M-dwarf Opportunity: Characterizing Nearby M-Dwarf Habitable Zone Planets" and "Strange New Worlds: Characterizing Nearby M-Dwarf Habitable Zone Planets"
Artemis enabled Stellar Imager (AeSI)
NASA Innovative Advanced Concepts (NIAC) Program (selected for Phase 1 study in 2024).
This study investigates the details of building a high-resolution imaging interferometer near the South Pole of the Moon in conjunction with the Artemis Program.
https://hires.gsfc.nasa.gov/si/aesi.html
Tell Me How I'm Supposed to Breathe With No Air - JWST Transmission Spectra of Rocky Worlds
We are conducting a Large Cycle 1 GO Program to survey 5 rocky exoplanets around the "cosmic shoreline" to search for evidence of atmospheres. So far, two transmission spectra are featureless, consistent with cosmic shoreline predictions of no substantial atmosphere, and two others deviate from a flat line, consistent with either H2O-rich atmospheres or starspots.
Star-Planet Activity Research CubeSat (SPARCS)
Science Team Member for the NASA-funded APRA mission, SPARCS (set to launch early 2026): a 6U cubesat monitoring flares and sunspot activity on M dwarfs in the far- and near-ultraviolet
Education
Ph.D., Planetary Sciences, University of Arizona, 2019
Minor: Astrobiology
Dissertation: Predicting the Extreme Ultraviolet Radiation Environment of Exoplanets Around Low-Mass Stars
M.Sc., Planetary Sciences, University of Arizona, 2016
B.A., Astronomy-Physics, University of Virginia, 2013
Awards
ASD Peer Award, 2023
Gerard P. Kuiper Memorial Award, 2020
NASA Earth and Space Science Fellowship, 2015 – 2018
UA College of Science Galileo Circle Scholarship, 2016
Grants
Completing Panchromatic Spectra for High Priority HWO Target Stars (HST Cycle 33; #18001) - STScI - Awarded: 2025-08-01
Dates: -
PHOENIX EUV Grid and Stellar Ultraviolet Spectra (PEGASUS) Webtool - NASA/GSFC Sellers Exoplanet Environments Collaboration - Awarded: 2024-10-01
Dates: -
Exposing the Lyman-alpha Profiles of Low-Mass Stars (HST Cycle 29; #16646) - HST Cycle 29 - Awarded: 2021-08-12
Dates: -
Leveraging High Radial Velocities to Get to the Core of Planetary Lyman alpha Transits (Program-16731) - HST Cycle 29 - Awarded: 2021-08-12
Tell Me How I’m Supposed to Breathe With No Air: Measuring the Prevalence and Diversity of M-Dwarf Planet Atmospheres (Program-0198) - JWST Cycle 1 - Awarded: 2021-03-30
Observing the Lyman-alpha Transits of Two Sub-Neptunes Orbiting a 400 Myr G Star to Illuminate the Cause of the Exoplanet Radius Valley (Program-16455) - HST Cycle 28 - Awarded: 2020-11-09
Special Experience
American Astronomical Society
Congressional Visit Day Participant, 2019
The National Academies of Sciences, Engineering, and Medicine
Lloyd V. Berkner Space Policy Intern, Space Studies Board, 2016
Selected Publications
Refereed
2025. "Minimizing Star-spot Contamination of Exoplanet Transit Spectroscopy Using Alternate Normalization.", The Astronomical Journal, 170 (1): 11 [10.3847/1538-3881/add531] [Journal Article/Letter]
2025. "The Impact of Stellar Flares on the Atmospheric Escape of Exoplanets Orbiting M Stars. I. Insights from the AU Mic System.", The Astrophysical Journal, 985 (1): 100 [10.3847/1538-4357/adc932] [Journal Article/Letter]
2025. "Hydrogen escaping from a pair of exoplanets smaller than Neptune.", Nature, 638 (8051): 636-639 [10.1038/s41586-024-08490-x] [Journal Article/Letter]
2025. "The Magnetically Induced Radial Velocity Variation of Gliese 341 and an Upper Limit to the Mass of Its Transiting Earth-sized Planet.", The Astrophysical Journal, 979 (2): 214 [10.3847/1538-4357/ad9dd3] [Journal Article/Letter]
2025. "A High-resolution Spectroscopic Survey of Directly Imaged Companion Hosts. I. Determination of Diagnostic Stellar Abundances for Planet Formation and Composition.", The Astronomical Journal, 169 (2): 55 [10.3847/1538-3881/ad8dfc] [Journal Article/Letter]
2024. "X-Ray Emission of Nearby Low-mass and Sunlike Stars with Directly Imageable Habitable Zones.", The Astrophysical Journal Supplement Series, 275 (1): 1 [10.3847/1538-4365/ad71d6] [Journal Article/Letter]
2024. "Artemis-enabled stellar imager (AeSI): a Lunar long-baseline UV/optical imaging interferometer.", Optical and Infrared Interferometry and Imaging IX, 13095 54 [10.1117/12.3028797] [Proceedings]
2024. "Assembly, integration, and testing of the Star-Planet Activity Research CubeSat (SPARCS).", Space Telescopes and Instrumentation 2024: Ultraviolet to Gamma Ray, 13093 119 [10.1117/12.3018163] [Proceedings]
2024. "Photometric calibration in the ultraviolet of the Star-Planet Activity Research CubeSat (SPARCS).", Space Telescopes and Instrumentation 2024: Ultraviolet to Gamma Ray, 13093 120 [10.1117/12.3019065] [Proceedings]
2024. "A Multiwavelength Survey of Nearby M Dwarfs: Optical and Near-ultraviolet Flares and Activity with Contemporaneous TESS, Kepler/K2, Swift, and HST Observations.", The Astrophysical Journal, 971 (1): 24 [10.3847/1538-4357/ad487d] [Journal Article/Letter]
2024. "Correlating Intrinsic Stellar Parameters with Mg ii Self-reversal Depths.", The Astrophysical Journal, 964 (1): 80 [10.3847/1538-4357/ad22da] [Journal Article/Letter]
2024. "JWST/NIRCam Transmission Spectroscopy of the Nearby Sub-Earth GJ 341b.", The Astronomical Journal, 167 (3): 90 [10.3847/1538-3881/ad19df] [Journal Article/Letter]
2024. "Atmospheric Escape From Three Terrestrial Planets in the L 98-59 System.", The Astrophysical Journal, 961 (1): 115 [10.3847/1538-4357/ad0e0e] [Journal Article/Letter]
2023. "Double Trouble: Two Transits of the Super-Earth GJ 1132 b Observed with JWST NIRSpec G395H.", The Astrophysical Journal Letters, 959 (1): L9 [10.3847/2041-8213/ad054f] [Journal Article/Letter]
2023. "A JWST transmission spectrum of the nearby Earth-sized exoplanet LHS 475 b.", Nature Astronomy, 7 (11): 1317-1328 [10.1038/s41550-023-02064-z] [Journal Article/Letter]
2023. "Modeling the Chromosphere and Transition Region of Planet-hosting Star GJ 436.", The Astrophysical Journal, 954 (1): 73 [10.3847/1538-4357/ace103] [Journal Article/Letter]
2023. "HAZMAT. IX. An Analysis of the UV and X-Ray Evolution of Low-mass Stars in the Era of Gaia.", The Astrophysical Journal, 951 (1): 44 [10.3847/1538-4357/acd2dc] [Journal Article/Letter]
2023. "High Tide or Riptide on the Cosmic Shoreline? A Water-rich Atmosphere or Stellar Contamination for the Warm Super-Earth GJ 486b from JWST Observations.", The Astrophysical Journal Letters, 948 (1): L11 [10.3847/2041-8213/accb9c] [Journal Article/Letter]
2023. "The effect of stellar contamination on low-resolution transmission spectroscopy: needs identified by NASA’s Exoplanet Exploration Program Study Analysis Group 21.", RAS Techniques and Instruments, 2 (1): 148-206 [10.1093/rasti/rzad009] [Journal Article/Letter]
2022. "Accurate Modeling of Lyman-alpha Profiles and their Impact on Photolysis of Terrestrial Planet Atmospheres.", The Astrophysical Journal, [10.3847/1538-4357/ac77f2] [Journal Article/Letter]
2021. "Onboard dynamic image exposure control for the Star–Planet Activity Research CubeSat (SPARCS).", Monthly Notices of the Royal Astronomical Society, 509 (4): 5702-5712 [10.1093/mnras/stab3396] [Journal Article/Letter]
2021. "Time-Resolved Photometry of the High-Energy Radiation of M Dwarfs with the Star-Planet Activity Research CubeSat (SPARCS).", Astronomische Nachrichten, [10.1002/asna.20210068] [Journal Article/Letter]
2021. "A New Look into K-giants' Chromospheres.", Research Notes of the American Astronomical Society, 5 (4): 73 [10.3847/2515-5172/abf4e4] [Journal Article/Letter]
2021. "HAZMAT. VII. The Evolution of Ultraviolet Emission with Age and Rotation for Early M Dwarf Stars.", The Astrophysical Journal, 907 (2): 91 [10.3847/1538-4357/abd0f0] [Journal Article/Letter]
2020. "SPARCS payload assembly, integration, and test update.", Society of Photo-Optical Instrumentation Engineers (SPIE) Conference Series, 11444 114440A [10.1117/12.2562582] [Proceedings]
2020. "Estimating the Ultraviolet Emission of M Dwarfs with Exoplanets from Ca II and H-alpha.", The Astronomical Journal, 160 (6): 269 [10.3847/1538-3881/abbf5c] [Journal Article/Letter]
2020. "HAZMAT VI: The Evolution of Extreme Ultraviolet Radiation Emitted from Early M Stars.", The Astrophysical Journal, 895 (1): 5 [10.3847/1538-4357/ab893a] [Journal Article/Letter]
2020. "Current Population Statistics Do Not Favor Photoevaporation over Core-powered Mass Loss as the Dominant Cause of the Exoplanet Radius Gap.", The Astrophysical Journal, 890 (1): 23 [10.3847/1538-4357/ab6605] [Journal Article/Letter]
2019. "Predicting the Extreme Ultraviolet Radiation Environment of Exoplanets around Low-mass Stars: GJ 832, GJ 176, and GJ 436.", The Astrophysical Journal, 886 (2): 77 [10.3847/1538-4357/ab4f6f] [Journal Article/Letter]
2019. "Predicting the Extreme Ultraviolet Radiation Environment of Exoplanets around Low-mass Stars: The TRAPPIST-1 System.", The Astrophysical Journal, 871 (2): 235 [10.3847/1538-4357/aaf891] [Journal Article/Letter]
2018. "HAZMAT. IV. Flares and Superflares on Young M Stars in the Far Ultraviolet.", The Astrophysical Journal, 867 (1): 70 [10.3847/1538-4357/aae2ae] [Journal Article/Letter]
2017. "Stellar and Planetary Parameters for K2textquoterights Late-type Dwarf Systems from C1 to C5.", The Astrophysical Journal, 837 (1): 72 [10.3847/1538-4357/aa56c7] [Journal Article/Letter]
2017. "A New Model of Roche Lobe Overflow for Short-period Gaseous Planets and Binary Stars.", The Astrophysical Journal, 835 (2): 145 [10.3847/1538-4357/835/2/145] [Journal Article/Letter]
2016. "Tidal decay and stable Roche-lobe overflow of short-period gaseous exoplanets.", Celestial Mechanics and Dynamical Astronomy, 126 (1-3): 227-248 [10.1007/s10569-016-9704-1] [Journal Article/Letter]
2014. "Predicting Lyensuremathalpha and Mg II Fluxes from K and M Dwarfs Using Galaxy Evolution Explorer Ultraviolet Photometry.", Astrophysical Journal Letters, 796 (1): L20 [10.1088/2041-8205/796/1/L20] [Journal Article/Letter]