Research

A select list of honors, awards, and grants as well as a broad description of some of my recent research can be found below. My complete CV can be found here. A comprehensive list of my publications can also be found at ADS.

The following honors, awards, and grants have helped support my research:

  • 2017: Hubble Space Telescope GO Cycle 25
  • 2016-2019: NASA WIYN PI Data Awards
  • 2014: Theodore Dunham, Jr., Fund for Astrophysical Research Grant
  • 2010-2011: National Geographic Society, Young Explorers Grant
  • 2010-2011: American Philosophical Society, Lewis and Clark Fund for Exploration and Field Research in Astrobiology
  • 2009-2012: National Science Foundation Graduate Research Fellowship

I have also been awarded observing time on the following facilities (as principal investigator):

  • 2017: 9 orbits on the Hubble Space Telescope
    • Near-infrared exoplanet transit spectroscopy to measure the spectrum of KELT-11b.
  • 2017: 15 hours on the Spitzer Space Telescope
    • Near-infrared exoplanet eclipse photometry to characterize thermal emission from KELT-11b.
  • 2016-2019: 46 nights on the 3.5-meter WIYN Telescope
    • Near-infrared exoplanet transit photometry for exoplanet confirmation and characterization.
  • 2015: 6 nights on the 4-meter Mayall Telescope
    • Near-infrared exoplanet eclipse photometry to characterize exoplanet thermal emission.
  • 2013: 1 night on the 10-meter Keck II Telescope
    • Optical spectroscopy for characterization of exoplanet host stars.
  • 2013: 3 nights on the 2.2-meter University of Hawaii Telescope
    • Optical exoplanet transit photometry for exoplanet confirmation and characterization.
  • 2010–2012: 75.2 hours (9.4 nights) on the 10.4-meter Gran Telescopio Canarias
    • Optical narrow-band exoplanet transit photometry for exoplanet confirmation and characterization.


Transiting Exoplanets

My research focuses on the study of transiting extrasolar planets. An extrasolar planet, or exoplanet, is a planet that is located outside of the Solar System and orbits a star other than the Sun. A transiting planet is a planet that passes in front of its host star as observed from Earth. We can observe the dip in the brightness of the star that is caused by the planet during the transit, as illustrated in the following image.

Image Credit: NASA Ames


Measuring Exoplanet Atmospheres

By measuring the change in brightness of the host star (i.e. the transit depth), we can determine the radius of the planet plus the extent of its atmosphere. Measuring the transit depth at different wavelengths of light then allows us to extract information about the composition of the planet's atmosphere, illustrated in the figure below.

Image Credit: ESA with adaptations by David Sing

With this technique (also known as transmission spectroscopy or spectrophotometry), we can determine which molecules or atoms are present and absorbing starlight in the planet's atmosphere.

My recent research has focused on using transmission spectrophotometry to study the atmospheres of two types of planets: hot Jupiters and super Earths. I presented one of the first detections of potassium in an exoplanet atmosphere in Colón et al. (2012a). In that paper, I used the 10.4-meter Gran Telescopio Canarias to measure a ~4.2% change in the radius of the hot Jupiter HD 80606b around the wavelengths where potassium would be absorbing. This is illustrated in the figure below.

Figure 14 from Colón et al. (2012a)

In Colón & Gaidos (2013) and Wilson, Colón et al. (2014), I used the 3.8-meter United Kingdom Infrared Telescope and the 10.4-meter Gran Telescopio Canarias to probe the atmosphere of the super-Earth GJ 1214b. Observations revealed a flat, featureless spectrum for the planet's atmosphere. This suggests that GJ 1214b has some cloud or haze layer that is obscuring any absorption features.

Figure 8 from Colón & Gaidos (2013)

The red point is from the UKIRT observations, compared to other published data (other points) and some atmosphere models (solid curves).

Figure 13 from Wilson, Colón et al. (2014)

The colored points are the UKIRT data, compared to different atmosphere models (solid curves).


Vetting Candidate Planets

Besides atmospheric studies, I have also worked on confirming the planetary nature of candidate transiting planets discovered by the Kepler mission. I used observations from the 10.4-meter Gran Telescopio Canarias taken at different wavelengths to check if the transit depths were consistent between the different passbands. In this case, a significantly different transit depth would indicate that the object transiting the target star was not a planet at all. Instead, the object would be another star, making the system an eclipsing binary star and a "false positive". Using this technique, I validated two candidates as being actual planets and three candidates as being eclipsing binary stars.

Figure 8 from Colón et al. (2012b)

Multi-color transit light curves validating KOI 526.01 as a planet.

Figure 9 from Colón et al. (2012b)

Multi-color transit light curves identifying KOI 1187.01 as a false positive.

I am now using the same technique described above to confirm and characterize exoplanet candidates discovered by the NASA K2 mission. In particular, I am using the WHIRC infrared imager on the 3.5-meter WIYN telescope (pictured below) to observe K2 exoplanet candidates in transit in the near-infrared.

Stay tuned for more updates!