Search Publications
High-precision Dark Halo Virial Masses from Globular Cluster Numbers: Implications for Globular Cluster Formation and Galaxy Assembly
Forbes, Duncan A.; Burkert, Andreas
We confirm that the number of globular clusters (GCs), NGC, is an excellent tracer of their host galaxy's halo virial mass, Mvir. The simple linear relation Mvir = 5 × 109 M⊙ × NGC fits the data perfectly from Mvir = 1010 M⊙ to Mvir = 2 × …
Debris Disk Results from the Gemini Planet Imager Exoplanet Survey's Polarimetric Imaging Campaign
Matthews, Brenda C.; Duchêne, Gaspard; Esposito, Thomas M. +62 more
We report the results of a ∼4 yr direct imaging survey of 104 stars to resolve and characterize circumstellar debris disks in scattered light as part of the Gemini Planet Imager (GPI) Exoplanet Survey. We targeted nearby (≲150 pc), young (≲500 Myr) stars with high infrared (IR) excesses (LIR/L⋆ > 10-5), includin…
The Featureless Transmission Spectra of Two Super-puff Planets
Fortney, Jonathan J.; Désert, Jean-Michel; Line, Michael R. +9 more
The Kepler mission revealed a class of planets known as "super-puffs," with masses only a few times larger than Earth's but radii larger than Neptune, giving them very low mean densities. All three of the known planets orbiting the young solar-type star Kepler 51 are super-puffs. The Kepler 51 system thereby provides an opportunity for a comparati…
New Grids of Pure-hydrogen White Dwarf NLTE Model Atmospheres and the HST/STIS Flux Calibration
Rauch, Thomas; Hubeny, Ivan; Bohlin, Ralph C.
Nonlocal thermodynamic equilibrium (NLTE) calculations of hot white dwarf (WD) model atmospheres are the cornerstone of modern flux calibrations for the Hubble Space Telescope and for the CALSPEC database. These theoretical spectral energy distributions (SEDs) provide the relative flux versus wavelength, and only the absolute flux level remains to…
ARES I: WASP-76 b, A Tale of Two HST Spectra
Drossart, Pierre; Blain, Doriann; Beaulieu, Jean-Philippe +25 more
We analyze the transmission and emission spectra of the ultra-hot Jupiter WASP-76 b, observed with the G141 grism of the Hubble Space Telescope's (HST) Wide Field Camera 3 (WFC3). We reduce and fit the raw data for each observation using the open-source software Iraclis before performing a fully Bayesian retrieval using the publicly available anal…
ARES. II. Characterizing the Hot Jupiters WASP-127 b, WASP-79 b, and WASP-62b with the Hubble Space Telescope
Drossart, Pierre; Blain, Doriann; Beaulieu, Jean-Philippe +24 more
This paper presents the atmospheric characterization of three large, gaseous planets: WASP-127 b, WASP-79 b, and WASP-62 b. We analyzed spectroscopic data obtained with the G141 grism (1.088-1.68 µm) of the Wide Field Camera 3 on board the Hubble Space Telescope using the Iraclis pipeline and the TauREx3 retrieval code, both of which are pub…
The High-energy Radiation Environment around a 10 Gyr M Dwarf: Habitable at Last?
Loyd, R. O. Parke; Kowalski, Adam F.; Brown, Alexander +20 more
Recent work has demonstrated that high levels of X-ray and UV activity on young M dwarfs may drive rapid atmospheric escape on temperate, terrestrial planets orbiting within the habitable zone. However, secondary atmospheres on planets orbiting older, less active M dwarfs may be stable and present more promising candidates for biomarker searches. …
A Dynamical Mass of 70 ± 5 MJup for Gliese 229B, the First T Dwarf
Dupuy, Trent J.; Bardalez Gagliuffi, Daniella C.; Bowler, Brendan P. +4 more
We combine Keck/HIRES radial velocities, imaging with HiCIAO/Subaru and the Hubble Space Telescope, and absolute astrometry from Hipparcos and Gaia to measure a dynamical mass of 70 ± 5 ${M}_{\mathrm{Jup}}$ for the brown dwarf companion to Gl 229. Gl 229B was the first imaged brown dwarf to show clear signs of methane in its atmosphere. Cooling mo…
Updated Parameters and a New Transmission Spectrum of HD 97658b
Mikal-Evans, Thomas; Henry, Gregory W.; Knutson, Heather A. +23 more
Recent years have seen increasing interest in the characterization of sub-Neptune-sized planets because of their prevalence in the Galaxy, contrasted with their absence in our solar system. HD 97658 is one of the brightest stars hosting a planet of this kind, and we present the transmission spectrum of this planet by combining four Hubble Space Te…
Constraints on Metastable Helium in the Atmospheres of WASP-69b and WASP-52b with Ultranarrowband Photometry
Tinyanont, Samaporn; Millar-Blanchaer, Maxwell A.; Knutson, Heather A. +7 more
Infrared observations of metastable 23S helium absorption with ground- and space-based spectroscopy are rapidly maturing, as this species is a unique probe of exoplanet atmospheres. Specifically, the transit depth in the triplet feature (with vacuum wavelengths near 1083.3 nm) can be used to constrain the temperature and mass-loss rate …