Sarah Peacock

Planetary Scientist


Ph.D. (in progess), in Planetary Science, University of Arizona, Lunar and Planetary Laboratory

M.S., in Planetary Science, University of Arizona, Lunar and Planetary Laboratory

B.A., in Astronomy-Physics, University of Virginia

About Me

I am a sixth year doctoral candidate studying planetary science at the University of Arizona's Lunar and Planetary Lab. I am interested in stellar upper-atmospheres, specifically the ultraviolet radiation emitted by M dwarfs stars. My research is important in determining if a planet located in the commonly-defined habitable zone around these types of stars is truly habitable by improving our understanding of the evolution of planetary atmospheres as they are subjected to large amounts of high energy radiation.


The chemistry and evolution of planetary atmospheres depends on the evolution of the high-energy radiation emitted by its host star. High levels of extreme ultraviolet (EUV) radiation can drastically alter planetary atmospheres through ionizing, heating, expanding, chemically modifying, and eroding them during the first few billion years of a planetary lifetime. Current capabilities allow for far-UV and limited X-ray measurements, but observing stars other than the Sun across the EUV is impossible due to a lack of instruments operating in the necessary wavelength range. My research entails using the PHOENIX stellar atmosphere code to model the upper atmospheres of stars in order to determine how much EUV radiation is emitted. My models include prescriptions for the stellar photosphere, chromosphere and transition region are constrained using far- and near-UV obsertaions of the star.

The Sun in the X-ray (94 Å)

The Sun in the EUV (211 Å)

The Sun in the UV (1700 Å)

The above images of the Sun courtesy of NASA/SDO and the AIA, EVE, and HMI science teams.

My research focuses on modeling M dwarf stars: stars that are smaller and cooler than the Sun. M dwarf stars are the most common spectral type in our galaxy, making up nearly 75 % of the Milky Way's stellar population. Due to their cool effective temperatures (~ 3000 K), the canonical habitable zone around M dwarfs lies between just 0.1 and 0.4 AU. Their low masses and luminosities allow for easier detection of small, transiting rocky planets orbiting at these small separations, occurring at a rate of 0.1 to 0.6 planets per star.

Below is an example PHOENIX model spectrum (navy) of the M dwarf star, GJ176, as compared to the observed spectrum (red). The observed spectrum is from the MUSCLES HST Treasury Survey [France+ 2016; ApJ 820:89F]. The MUSCLES spectrum contains Chandra/XMM-Newton X-ray observations, empirically derived relations to compute the EUV spectrum, and observed HST COS and STIS spectra covering the Far-UV and Near-UV regions.


Star-Planet Activity Research CubeSat

I am also a member of the science team for the SPARCS cubesat led by PI Evgenya Shkolnik. SPARCS is a NASA funded 6U CubeSat dedicated to monitoring the high-energy radiation environment around low mass stars. Set to launch after October 2021, this one-year mission will measure short- and long-term variability of ~10 stars simultaneously in the far and near ultraviolet. My role on the team is to provide model spectra for these stars based on the SPARCS photometric measurements.

The Art of Planetary Science

Art is rad.

The Art of Planetary Science is an annual art exhibit put on by the graduate students of LPL. I have had the pleasure of co-organizing the event for the past four years with the rest of the TAPS team: Jamie Molaro, James Keane, Hannah Tanquary, Theresa Hentz, and Tracy Esman.

This show acts as a way to bring together Tucson's art and astronomy communities through displays of art created from and inspired by the solar system and the scientific data with which we explore it. This past year, the show had over 200 submissions, with works from over 120 artists and scientists. Through this experience, we are able to connect with both the art community and over 1000 members of the public each year to share how planetary science is creative and beautiful.

Check out our website: for more information about the event.

The TAPS team: J. Molaro, H. Tanquary, S. Peacock, J. Keane

First floor, opening night of our 2015 show

Art from the 2015 show before hanging

Acrylic Pours

My work with The Art of Plantery Science has inspired me to explore and play with different styles of art. Throughout the years I have created and exhibited pieces including yarn quipus counting various expolanet statistics, laser spirographs inspired by the ChemCam on the Curiosity rover, and an M dwarf stellar spectrum visualized as an aluminum windchime. In 2018 I started creating planetary science-inpsired acrylic pours:

Jupiter #1, 2018, acrylic


Jupiter #2, 2018, acrylic


Jupiter #1, 2018, acrylic


Untitled, 2018, acrylic

Dust Storm on Mars, 2018, acrylic


Protoplanetary Disk, 2018, acrylic

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