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<!DOCTYPE HTML>
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<!--<span class="date">April 25, 2017</span>-->
<!--<h1><a href="#">blah blah blah</a></h1>-->
<p style="font-style: normal;">My graduate school work focuses on discovering and characterizing transiting exoplanets with a variety of
techniques. Primarily, I've been working on exoplanet atmospheric transmission spectroscopy with Hubble and JWST,
although we also use ground-based transit spectroscopy, as well as radial velocity measurements, and dynamical analyses with transit-timing
variations. I'm interested in general in the population of Neptune-sized exoplanets, especially those in the Neptune Desert, where these
planets are rare.
</p>
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<section class="posts" style="font-size: smaller;">
<article>
<header>
<h5>KU - JWST Transmission Spectroscopy</h5>
</header>
<a class="image fit"><img src="images/w39b_atmosphere.jpeg" alt="" /></a>
<p>
In order to enable accurate, reproducible, and timely science with JWST, I've been working with the
<a href="https://github.com/kevin218/Eureka">Eureka!</a> team to develop an open-source JWST data reduction and analysis pipeline.
Eureka! is open-source, supports both photometry and spectroscopy observations, and can handle any point in the analysis pipeline from
uncalibrated detector images to plotting fully-fit transmission spectra.
As part of the <a href="https://ers-transit.github.io/">JWST Transiting Exoplanet Community Early Release Science</a> program, I had
the opportunity to apply this work to <a href="https://exoplanets.nasa.gov/news/1715/nasas-webb-reveals-an-exoplanet-atmosphere-as-never-seen-before/">
actual JWST transit spectroscopy observations of the Hot Saturn WASP-39 b.</a> Our first five papers,
describing each NIR spectroscopy mode as well as initial modeling of the chemical makeup of the planet's atmosphere, show the first
detections of carbon dioxide and sulfur dioxide in any exoplanet atmosphere. More work on this planet is incoming, as we analyze new
mid-infrared data from JWST.
</p>
</article>
<article>
<header>
<h5>KU - Water Vapor on TOI-674 b</h5>
</header>
<a class="image fit"><img src="images/TOI-674b_1280.jpeg" alt="" /></a>
<p>With my advisor, Ian Crossfield, and building on some previous work I was doing at NASA GSFC with Tom Barclay and Elisa Quintana,
I've been working on characterizing TESS-discovered exoplanets using the Hubble Space Telescope's near-infrared spectrographs.
I recently led a paper showing evidence of water vapor in the atmosphere of the warm Neptune TOI-674 b. As a Neptune desert planet,
TOI-674 b poses some questions for our understanding of planetary formation and evolution, and future characterization of this
planet's atmosphere may help us answer some of these.
<a href="https://exoplanets.nasa.gov/news/1698/discovery-alert-water-vapor-detected-on-a-super-neptune/">Check out the NASA press release,</a>
as well as <a href="https://iopscience.iop.org/article/10.3847/1538-3881/ac8b7e">the open-access paper!</a>
</p>
</article>
<article>
<header>
<h5>NASA - The Exoplanet Modeling and Analysis Center</h5>
</header>
<a class="image fit"><img src="images/emac_logo_cropped.jpg" alt="" /></a>
<p>A key project of the SEEC collaboration is the <a href="https://emac.gsfc.nasa.gov">Exoplanet Modeling and Analysis Center</a>,
which aims to be a community repository for exoplanet modeling tools and resources. I'm on the EMAC development team, working on
tool vetting, model development, and implementation. In particular, I've recently helped implement the
<a href="https://tools.emac.gsfc.nasa.gov/EBC/">Exoplanet Boundary Calculator</a>, and externally, the
<a href="https://psg.gsfc.nasa.gov/apps/exopsg.php">Exoplanetary Spectrum Generator interface</a>. EMAC development
is ongoing, and we're currently accepting <a href="https://emac.gsfc.nasa.gov/submissions/">submissions</a> for future tools. </p>
</article>
<article>
<header>
<h5>NASA - JWST Direct Imaging Simulations</h5>
</header>
<a class="image"><img src="images/832b_coro.png"/></a>
<p>This work has recently been accepted for publication in the Astronomical Journal.
<a href="Brande_JWST_Accepted.pdf">Find the paper here.</a>
</p>
<p>I've been investigating the potential utility of the James Webb Space Telescope for challenging direct imaging observations.
Specifically, I've been looking at how we might use the Mid-Infrared Instrument coronagraphs to search for nearby cold (250-350 K)
Jovian planets around M-dwarf hosts. Within 5 parsecs of Earth, there are nearly 30 potential stellar targets, and one known
Jovian-mass exoplanet, GJ 832b. GJ 832b is not known to transit, hasn't had recent long-baseline RV observations, and has only
a ~0.69″ separation from its host star, so recovering the planet with JWST would be useful in characterizing the planet.
In under 6.25hr of integration time, GJ 832b could be feasibly detected by MIRI, and with a number of observations spaced
over a period of some years, we might be able to characterize the planet's orbit and break the <i>Msin(i)</i> degeneracy to
get a more accurate planetary mass estimate. </p>
</article>
<article>
<header>
<h5><a>NASA - TESS Planet Candidate Confirmation and Characterization</a></h5>
</header>
<a class="image fit"><img src="images/l98-transit-plot3.png"/></a>
<p>I work closely with researchers in the Exoplanets and Stellar Astrophysics Lab on TESS Planet Candidate analysis.
When a promising candidate is identified by our pipeline, we work with follow up teams to get other observations to
confirm the planetary nature of the transit signal.
<a href=https://ui.adsabs.harvard.edu/abs/2019AJ....158...32K/abstract>Recently, we described a system of three terrestrial
planets orbiting a nearby M-dwarf, L 98-59.</a> As this is a multiplanet system, it is an interesting system to investigate
dynamically. We modeled the dynamic behavior of the system to determine whether or not the system was likely to have
detectable transit-timing variations that would allow us to either constrain the masses of the planets, or infer the
presence of as-yet undiscovered planets in the system. From our analysis, we found that the transit data is well-described
by simple circular orbit models for each individual planet, and we found no significant transit-timing variations.
<a href=https://www.nasa.gov/feature/goddard/2019/nasa-s-tess-mission-finds-its-smallest-planet-yet/>I also had the opportunity to talk to one of the NASA science
writers in the agency news release about L98-59bcd!</a>
</p>
</article>
<article>
<header>
<h5>UMD - Complex Asteroid Gravity Fields</h5>
</header>
<!--<a href="#" class="image fit"><img src="images/pic05.jpg" alt="" /></a>-->
<p>As an undergraduate at the University of Maryland, I worked with Dr. Doug Hamilton on implementing new algorithms to approximate the complex gravity
fields near the surfaces of irregularly shaped asteroids. Far away from an asteroid's surface, approximating the body by a spheroid of equal mass
suffices. However, for robotic probe missions that intend on interacting more closely with their targets, a weird, lumpy body may prove challenging or
impossible to plot stable trajectories around. Approximating an asteroid by a number of spherical elements would give a very simple solution to calculating
the gravity of the individual elements, but is complicated by the fact that spheres do not evenly pack, leading to voids in the volume. Using cubic elements
would be convenient, as cubes evenly pack and are often used to approximate complex volumes, but the analytic solution of a cube's gravity is less convenient
to work with than a sphere. Asteroids may also have internal voids and other density variations, and our implementation will be flexible enough to accommodate
these. When I graduated, we had implemented the algorithm to calculate the gravity of large rectangular prisms, approximated by various cubic subelements. </p>
</article>
<article>
<header>
<h5>UMD - Orbit Visualization Tools</h5>
</header>
<a class="image fit"><img src="images/orbit.png"/></a>
<p>In addition to my research work with Dr. Hamilton at UMD, I also took his orbital mechanics class in 2017. Over the years, the UMD Astronomy department has
produced a series of educational tools to help students and the public learn astronomical concepts. Over the course of the class, we used the orbital
<a href="http://janus.astro.umd.edu/AW/awtools.html#orbits">element viewers and orbit integrators</a>, as well as writing our own tools to help us with
the course materials. For planar orbits, these tools work perfectly as the default views were static 2-dimensional plots. However, when expanding to
3-dimensional orbits, some imagination is needed to fully understand how the 2-D plot is colored to represent motion and position out of the plane
of the screen. I adapted a 3-D visualization view I'd written while working at the Chandra X-Ray Observatory one summer and some earlier code I had
written for the orbits class to provide a <a href="http://janus.astro.umd.edu/orbits/3dview.html">fully interactive 3-D view of an orbit given a set
of all six orbital elements</a>.
</p>
</article>
<!--<article>
<header>
<h5>Unstarted and Unfinished Ideas</h5>
</header>
<p>Some things I'm interested in, but not necessarily working on at the moment:
<ul style="text-align: left;">
<li>Scientific ethics: Academic inclusion and institutional acountability. Safety standards in space exploration, planetary protection, and anticolonialism.</li>
<li>N-body simulations: planetary system formation and evolution, asteroid impacts, trajectory plotting/astronavigation</li>
<li>Modeling observations of active stars to disambiguate potential planetary transits from stellar surface activity</li>
<li>CubeSats/SmallSats, space debris mitigation</li>
<li>Astrostatistics/Big Data</li>
<li>General space history nerdery</li>
</ul>
</p>
</article>-->
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<ul><li>© Jonathan Brande 2020</li><li>Adapted from <a href="https://html5up.net">HTML5 UP</a></li><li>Background Image: <a href="http://heritage.stsci.edu/2016/13/index.html">The Hubble Heritage Project</a></li></ul>
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