Zachory K. Berta

Learn More
A decade ago, the detection of the first transiting extrasolar planet provided a direct constraint on its composition and opened the door to spectroscopic investigations of extrasolar planetary atmospheres. Because such characterization studies are feasible only for transiting systems that are both nearby and for which the planet-to-star radius ratio is(More)
We present an investigation of the transmission spectrum of the 6.5M⊕ planet GJ 1214b based on new ground-based observations of transits of the planet in the optical and near-infrared, and on previously published data. Observations with the VLT + FORS and Magellan + MMIRS using the technique of multi-object spectroscopy with wide slits yielded new(More)
We present optical photometry of 16 transits of the super-Earth GJ 1214b, allowing us to refine the system parameters and search for additional planets via transit timing. Starspot-crossing events are detected in two light curves, and the star is found to be variable by a few percent. Hence, in our analysis, special attention is given to systematic errors(More)
We report the detection of eclipses in GJ 3236, a bright (I = 11.6) very low mass binary system with an orbital period of 0.77 days. Analysis of lightand radial velocity curves of the system yielded component masses of 0.38 ± 0.02 and 0.28 ± 0.02 M⊙. The central values for the stellar radii are larger than the theoretical models predict for these masses, in(More)
The Transiting Exoplanet Survey Satellite (TESS) is a NASA-sponsored Explorer mission that will perform a wide-field survey for planets that transit bright host stars. Here, we predict the properties of the transiting planets that TESS will detect along with the EB stars that produce false-positive photometric signals. The predictions are based on Monte(More)
We present the first maximum-light ultraviolet (UV) through near-infrared (NIR) Type Ia supernova (SN Ia) spectrum. This spectrum of SN 2011iv was obtained nearly simultaneously by the Hubble Space Telescope at UV/optical wavelengths and the Magellan Baade telescope at NIR wavelengths. These data provide the opportunity to examine the entire maximum-light(More)
In the effort to characterize the masses, radii, and atmospheres of potentially habitable exoplanets, there is an urgent need to find examples of such planets transiting nearby M dwarfs. The MEarth Project is an ongoing effort to do so, as a ground-based photometric survey designed to detect exoplanets as small as 2R⊕ transiting mid-to-late M dwarfs within(More)
Using the SDSS spectroscopic sample, we estimate the dark matter halo spin parameter λ for ∼ 53, 000 disk galaxies for which MOPED star formation histories are available. We investigate the relationship between spin and total stellar mass, star formation history, and environment. First, we find a clear anti-correlation between stellar mass and spin, with(More)
The MEarth Project is a ground-based photometric survey intended to find planets transiting the closest and smallest main-sequence stars. In its first four years, MEarth discovered one transiting exoplanet, the 2.7R⊕ planet GJ1214b. Here, we answer an outstanding question: in light of the bounty of small planets transiting small stars uncovered by the(More)
  • 1