My first postdoc paper titled "Predicted Yield of Transits of Known Radial Velocity Exoplanets from the TESS Primary and Extended Missions" is now published on arXiv (at this link)!

Many of the >600 exoplanets discovered via the radial velocity (RV) method lack sufficient photometric observations to discover whether or not the planet transits its host. Acquiring this amount of photometric follow-up is pretty challenging, but the Transiting Exoplanet Survey Satellite (TESS) is currently combing the sky for transiting planets! How convenient, right?

My colleagues and I used statistical arguments to predict how many of the >600 known RV exoplanet systems ought to transit given their planetary, orbital, and stellar properties. Turns out, that number is around 25 exoplanets, which is more than double the number of RV exoplanets that are already known to transit! Of the remaining dozen or so, TESS will only find around 3 exoplanets. This is the result of the relative long-period nature of the known RV exoplanets compared to the relative short observational baseline that most of the sky will receive from TESS.

Equally exciting though, is the chance for dispositive null results. We predict that the TESS observations will confidently rule out transits for well over 100 known RV exoplanets. When it comes to photometric follow up for RV exoplanets, this is an unprecedented effort and a valuable addition to TESS' scientific legacy.

This paper is currently in press for publication in PASP (link to be posted soon!) and can also be viewed on arXiv (https://arxiv.org/abs/1811.06550).

02/2018: California Bound!

I am super excited to announce that I have accepted a postdoctoral position with Prof. Stephen Kane in the Earth Sciences Department at UC Riverside! I will continue to work on observational studies of gas-giant exoplanets, as well as a number of other projects related to Stephen’s and my interests. Definitely, keep an eye out for some cool, interdisciplinary results coming out of our group at Riverside in the very near future! My new appointment will be starting in early Fall 2018.

But first…I suppose I need to actually finish my PhD. Back to work!

12/2017: AGU Fall Meeting in NOLA

The 2017 Fall Meeting of the American Geophysical Union took place in New Orleans, LA in mid-December. As you can see in the picture, I presented some preliminary research I am doing with Prof. Paul Withers here at BU. Each of those 20 panels on my poster are electron density profiles from the ionosphere of Titan–Saturn’s largest moon! The profiles were inferred from radio occultation observations made by the Radio Science Subsystem onboard the Cassini Spacecraft. During a radio occultation, Cassini sends a radio signal to the Earth that is picked up by the Deep Space Network (DSN), which is a collection of gigantic radio dishes spread around the world. Check out the DSN website out of JPL that shows (in real time!) what spacecraft each station is communicating with. As the line of sight of the radio signal between the DSN and Cassini dips into the ionosphere of Titan, the presence of electrons alters the radio signal ever so slightly. To be specific, the electrons result in the radio waves experiencing a gradient in the index of refraction (I’m a sucker for a project involving atmospheric refraction), which alters the phase of the radio signal measured by DSN. Add in some mathematics and out comes an electron density profile. Over the course of the Cassini Mission, the ionosphere of Titan showed some interesting features, which still need to be explored in more detail. I hope to get these profiles up on NASA’s Planetary Data System soon, so the whole community can access them. Also, keep an eye out for a paper describing our radio analysis process…

05/2017: Teaching Award!

I was recognized as the 2016-2017 Outstanding Teaching Fellow in the Department of Astronomy by the Graduate School of Arts and Sciences at BU! I received this for my work in the undergraduate course AS107: Life Beyond Earth with Prof. Thomas Bania. After we taught this course in Fall 2016, it was listed as ones of BU’s Top 10 Epic Courses by BU Today. It is a fascinating class to be part of, and I was honored to receive this award.

12/2016: Phantom Stars in the Kepler Dataset!

United Kingdom Infrared Telescope (UKIRT) J-band image of Kepler-445 (center). The red cross denotes the expected position of the phantom star, which is supposedly the same magnitude as Kepler-445. As it turns out, the phantom star does not actually exist, but it still influenced the data processing in the Kepler pipeline. Adapted from Dalba et al. (2017) AJ, 153, 59.

I led a team of researchers that recently discovered a phantom star—present in the Kepler Input Catalog (KIC) and the Kepler pipeline but not an actual star—in the Kepler dataset. The discovery came about after an observing run of three transits of the supposed super-Earth exoplanet Kepler-445c at the Discovery Channel Telescope. The planetary and stellar properties of Kepler-445c and its host star were thought to be similar to GJ 1214b, so it was an enticing target for follow-up atmospheric characterization. However, the planetary radius returned from the initial characterization of the Kepler transit observations was flawed because a phantom star incorrectly diluted the transit depth. Now, we find that the radius of Kepler-445c is ~1.6 times that of the Earth, making it very difficult to tell if it is a rocky or gaseous exoplanet! We posit that the phantom star came to be after an error in an old stellar catalog propagated into the KIC and through the pre-data conditioning in the Kepler pipeline.

The good news is that phantom stars are likely rare in the Kepler dataset. Plus, a recent update to the Kepler pipeline should prevent against similar issues in the future. However, problems from stellar magnitude and position errors in old star catalogs may certainly arise in the dataset from the upcoming Transiting Exoplanet Survey Satellite (TESS) mission. The pixels on the TESS detectors will be ~5 times larger than those that flew on Kepler, making stellar crowding and transit dilution a serious concern!

This work is now published in the Astronomical Journal. You can also check out the full paper on the arXiv: https://arxiv.org/abs/1612.02432