Search Publications
Rotational Light Curves of Jupiter from Ultraviolet to Mid-infrared and Implications for Brown Dwarfs and Exoplanets
Fletcher, Leigh N.; Zhang, Xi; Orton, Glenn S. +7 more
Rotational modulations are observed on brown dwarfs and directly imaged exoplanets, but the underlying mechanism is not well understood. Here we analyze Jupiter’s rotational light curves at 12 wavelengths from the ultraviolet (UV) to the mid-infrared (mid-IR). The peak-to-peak amplitudes of Jupiter’s light curves range from subpercent to 4% at mos…
The Population of Pulsating Variable Stars in the Sextans Dwarf Spheroidal Galaxy
Mateo, Mario; Vivas, A. Katherina; Alonso-García, Javier +2 more
A large extension of the Sextans dwarf spheroidal galaxy, 7 deg2, has been surveyed for variable stars using the Dark Energy Camera at the Blanco Telescope at Cerro Tololo Inter-American Observatory, Chile. We report seven anomalous Cepheids, 199 RR Lyrae stars, and 16 dwarf Cepheids in the field. This is only the fifth extragalactic sy…
Revisiting the HIP 41378 System with K2 and Spitzer
Gorjian, Varoujan; Kane, Stephen R.; Schlieder, Joshua E. +12 more
We present new observations of the multiplanet system HIP 41378, a bright star (V = 8.9, K s = 7.7) with five known transiting planets. Previous K2 observations showed multiple transits of two Neptune-sized bodies and single transits of three larger planets (R P = 0.33R J , 0.47R J , 0.88R J …
Observations of Binary Stars with the Differential Speckle Survey Instrument. VIII. Measures of Metal-poor and Triple Stars from 2015 to 2018
Kane, Stephen R.; Howell, Steve B.; Hirsch, Lea A. +15 more
We present 248 speckle observations of 43 binary and 19 trinary star systems chosen to make progress in two main areas of investigation: the fundamental properties of metal-poor stars and star formation mechanisms. The observations were taken at the Gemini North and South telescopes during the period 2015 July to 2018 April, mainly with the Differ…
TOI-216b and TOI-216 c: Two Warm, Large Exoplanets in or Slightly Wide of the 2:1 Orbital Resonance
Latham, David W.; Esquerdo, Gilbert A.; Zhou, George +32 more
Warm, large exoplanets with 10-100 day orbital periods pose a major challenge to our understanding of how planetary systems form and evolve. Although high eccentricity tidal migration has been invoked to explain their proximity to their host stars, a handful reside in or near orbital resonance with nearby planets, suggesting a gentler history of i…
A Discrete Set of Possible Transit Ephemerides for Two Long-period Gas Giants Orbiting HIP 41378
Omohundro, Mark; Vanderburg, Andrew; Hellier, Coel +22 more
In 2015, K2 observations of the bright (V = 8.9, K = 7.7) star HIP 41378 revealed a rich system of at least five transiting exoplanets, ranging in size from super-Earths to gas giants. The 2015 K2 observations only spanned 74.8 days, and the outer three long-period planets in the system were only detected with a single transit, so their orbital pe…
Identification of RR Lyrae Stars in Multiband, Sparsely Sampled Data from the Dark Energy Survey Using Template Fitting and Random Forest Classification
Bechtol, K.; Smith, M.; D'Andrea, C. B. +76 more
Many studies have shown that RR Lyrae variable stars (RRL) are powerful stellar tracers of Galactic halo structure and satellite galaxies. The Dark Energy Survey (DES), with its deep and wide coverage (g ∼ 23.5 mag in a single exposure; over 5000 deg2) provides a rich opportunity to search for substructures out to the edge of the Milky …
ACCESS: Ground-based Optical Transmission Spectroscopy of the Hot Jupiter WASP-4b
López-Morales, Mercedes; Jordán, Andrés; Espinoza, Néstor +6 more
We present an optical transmission spectrum of the atmosphere of WASP-4b obtained through observations of four transits with Magellan/IMACS, as part of the Arizona-CfA-Católica-Carnegie Exoplanet Spectroscopy Survey (ACCESS). Using a Bayesian approach to atmospheric retrieval, we find no evidence for scattering or absorption features in our transi…
Kronoseismology. IV. Six Previously Unidentified Waves in Saturn’s Middle C Ring
Nicholson, P. D.; Hedman, M. M.; French, R. G.
Recent studies of stellar occultations observed by the Visual and Infrared Mapping Spectrometer on board the Cassini spacecraft have demonstrated that multiple spiral wave structures in Saturn’s rings are probably generated by normal-mode oscillations inside the planet. Wavelet-based analyses have been able to unambiguously determine both the numb…
In-flight Characterization and Calibration of the Juno-ultraviolet Spectrograph (Juno-UVS)
Gérard, Jean-Claude; Kammer, Joshua A.; Gladstone, G. Randall +9 more
Juno is the first polar orbiter around Jupiter. Juno possesses a suite of instruments designed to measure the electron and ion populations in the Jupiter magnetosphere, leading to the powerful Jovian aurorae. The Ultraviolet Spectrograph onboard Juno (Juno-UVS) is a photon-counting imaging spectrograph (68-210 nm), designed to observe and characte…