Search Publications
Thermal modelling of water activity on comet 67P/Churyumov-Gerasimenko with global dust mantle and plural dust-to-ice ratio
Jorda, L.; Lamy, P. L.; Lara, L. M. +51 more
We perform a thermo-physical analysis on water activity of comet 67P/Churyumov-Gerasimenko (67P). The sublimation of water is assumed to occur from beneath a global, desiccated dust mantle over the irregular-shaped nucleus. The concept of two thermal models, the recipe of model formulation and the strategy of application to comet 67P are described…
Carbon Chain Anions and the Growth of Complex Organic Molecules in Titan’s Ionosphere
Lewis, G. R.; Coates, A. J.; Kataria, D. O. +13 more
Cassini discovered a plethora of neutral and ionized molecules in Titan’s ionosphere including, surprisingly, anions and negatively charged molecules extending up to 13,800 u q-1. In this Letter, we forward model the Cassini electron spectrometer response function to this unexpected ionospheric component to achieve an increased mass res…
An 80 au cavity in the disk around HD 34282
Pinte, C.; Ménard, F.; van der Plas, G. +5 more
Context. Large cavities in disks are important testing grounds for the mechanisms proposed to drive disk evolution and dispersion, such as dynamical clearing by planets and photoevaporation.
Aims: We aim to resolve the large cavity in the disk around HD 34282, whose presence has been predicted by previous studies modeling the spectral energy …
Investigating the Wave Nature of the Outer Envelope of Halo Coronal Mass Ejections
Vourlidas, Angelos; Kwon, Ryun-Young
We investigate the nature of the outer envelope of halo coronal mass ejections (H-CMEs) using multi-viewpoint observations from the Solar Terrestrial Relations Observatory-A, -B, and SOlar and Heliospheric Observatory coronagraphs. The 3D structure and kinematics of the halo envelopes and the driving CMEs are derived separately using a forward mod…
Various Local Heating Events in the Earliest Phase of Flux Emergence
Toriumi, Shin; Cheung, Mark C. M.; Katsukawa, Yukio
Emerging flux regions (EFRs) are known to exhibit various sporadic local heating events in the lower atmosphere. To investigate the characteristics of these events, especially to link the photospheric magnetic fields and atmospheric dynamics, we analyze Hinode, Interface Region Imaging Spectrograph (IRIS), and Solar Dynamics Observatory data of a …
ALMA Observations of Circumnuclear Disks in Early-type Galaxies: 12CO(2-1) and Continuum Properties
Ho, Luis C.; Barth, Aaron J.; Buote, David A. +4 more
We present results from an Atacama Large Millimeter/submillimeter Array (ALMA) Cycle 2 program to map CO(2-1) emission in nearby early-type galaxies (ETGs) that host circumnuclear gas disks. We obtained ∼0.″3 resolution Band 6 observations of seven ETGs selected on the basis of dust disks in Hubble Space Telescope images. We detect CO emission in …
DUSTiNGS. III. Distribution of Intermediate-age and Old Stellar Populations in Disks and Outer Extremities of Dwarf Galaxies
McQuinn, Kristen B. W.; Skillman, Evan D.; Boyer, Martha L. +8 more
We have traced the spatial distributions of intermediate-age and old stars in nine dwarf galaxies in the distant parts of the Local Group, using multi-epoch 3.6 and 4.5 µm data from the DUST in Nearby Galaxies with Spitzer (DUSTiNGS) survey. Using complementary optical imaging from the Hubble Space Telescope, we identify the tip of the red g…
Spectral properties of Martian and other planetary glasses and their detection in remotely sensed data
Mustard, John F.; Dyar, M. Darby; Cannon, Kevin M. +3 more
Thirty silicate glasses were synthesized as realistic analogs to those expected to exist on Mars, the Moon, and Mercury. Samples were measured using visible/near-infrared and Mössbauer spectroscopy to determine the effects of varying bulk chemistry, oxygen fugacity, and temperature on spectral properties. For Martian glasses, the fO2 du…
Size and Shape of Chariklo from Multi-epoch Stellar Occultations
Colas, F.; Bérard, D.; Lellouch, E. +28 more
We use data from five stellar occultations observed between 2013 and 2016 to constrain Chariklo’s size and shape, and the ring reflectivity. We consider four possible models for Chariklo (sphere, Maclaurin spheroid, triaxial ellipsoid, and Jacobi ellipsoid), and we use a Bayesian approach to estimate the corresponding parameters. The spherical mod…
Astrometry with Hubble Space Telescope Fine Guidance Sensors—A Review
Nelan, Edmund P.; Harrison, Thomas E.; Benedict, G. Fritz +1 more
Over the last 20 years, Hubble Space Telescope Fine Guidance Sensor interferometric astrometry has produced precise and accurate parallaxes of astrophysical interesting stars and mass estimates for stellar companions. We review parallax results, and binary star and exoplanet mass determinations, and compare a subset of these parallaxes with prelim…