Sarah Peacock

Planetary Scientist

CV

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 fifth year doctoral candidate studying planetary science at the University of Arizona's Lunar and Planetary Lab (LPL). I am interested in exoplanets and their atmospheres, specifically those around M dwarf stars. My research involves determining if a planet in the commonly-defined habitable zone is truly habitable by improving our understanding of the evolution of planetary atmospheres as they are subjected to large amounts of high energy radiation.

Research

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. Unfortunately, we are currently unable to observe in these wavelengths, but there are spectral observations of both shorter (x-ray) and longer (UV) wavelengths than the EUV. My research entails using the PHOENIX stellar atmosphere code to model the upper atmospheres of stars (where this energy comes from) in order to determine how much EUV radiation is emitted. Since we have x-ray and UV observations, I am able to constrain my models to the observed stellar spectra.

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.

Currently, I am focusing on modeling M dwarf stars: stars that are smaller and cooler than the Sun. The reason for selecting these low-mass stars is that their low luminosities produce habitable zones much closer to the star (~0.1-0.4 AU), making it easier to find terrestrial (and potentially habitable!) planets around them.

Below is my 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.

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 three years with the rest of the TAPS team: Jamie Molaro, James Keane, Hannah Tanquary - and joining our team in a big way this year, Theresa Hentz!

Tucson has two predominant communities: art and astronomy, and this show acts as a way to bring both worlds together. We display a variety 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.

Please join us for our upcoming show February 2-4, 2018! Check out our website: www.lpl.arizona.edu/art 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

   Contact

     speacock@lpl.arizona.edu
     T: (520) 621-7274

     Lunar and Planetary Laboratory
     Department of Planetary Sciences
     University of Arizona
     1629 E University Blvd
     Tucson, AZ 85721