Search Publications
Accurate Machine-learning Atmospheric Retrieval via a Neural-network Surrogate Model for Radiative Transfer
Arney, Giada N.; Domagal-Goldman, Shawn D.; Harrington, Joseph +8 more
Atmospheric retrieval determines the properties of an atmosphere based on its measured spectrum. The low signal-to-noise ratios of exoplanet observations require a Bayesian approach to determine posterior probability distributions of each model parameter, given observed spectra. This inference is computationally expensive, as it requires many exec…
A New UV Spectral Feature on Europa: Confirmation of NaCl in Leading-hemisphere Chaos Terrain
Alday, Juan; Roth, Lorenz; Brown, Michael E. +6 more
Recent visible-wavelength observations of Europa's surface obtained with the Hubble Space Telescope (HST) revealed the presence of an absorption feature near 450 nm that appears spatially correlated with leading-hemisphere chaos terrain. This feature was interpreted to reflect the presence of irradiated sodium chloride ultimately sourced from the …
A Survey of CO, CO2, and H2O in Comets and Centaurs
Bauer, James; Harrington Pinto, Olga; Womack, Maria +1 more
CO and CO2 are the two dominant carbon-bearing molecules in comae and have major roles in driving activity. Their relative abundances also provide strong observational constraints to models of solar system formation and evolution but have never been studied together in a large sample of comets. We carefully compiled and analyzed publish…
Photometric Observations of the Binary Near-Earth Asteroid (65803) Didymos in 2015-2021 Prior to DART Impact
Carry, B.; Souami, D.; Dotto, E. +24 more
We performed photometric observations of the binary near-Earth asteroid (65803) Didymos in support of the Double Asteroid Redirection Test (DART) mission that will test the Kinetic Impactor technology for diverting dangerous asteroids. It will hit the Didymos secondary, called Dimorphos, on 2022 September 26. We observed Didymos with 11 telescopes…
International Asteroid Warning Network Timing Campaign: 2019 XS
Popescu, Marcel; Granvik, Mikael; Chambers, Kenneth C. +69 more
As part of the International Asteroid Warning Network's observational exercises, we conducted a campaign to observe near-Earth asteroid 2019 XS around its close approach to Earth on 2021 November 9. The goal of the campaign was to characterize errors in the observation times reported to the Minor Planet Center, which become an increasingly importa…
Thermal Properties of 1847 WISE-observed Asteroids
Masiero, Joseph R.; Tholen, David J.; Hung, Denise +1 more
We present new thermophysical model fits of 1847 asteroids, deriving thermal inertia, diameter, and Bond and visible geometric albedo. We use thermal flux measurements obtained by the Wide-field Infrared Survey Explorer (WISE) during its fully cryogenic phase, when both the 12 µm (W3) and 22 µm (W4) bands were available. We take shape …
An Open-source Bayesian Atmospheric Radiative Transfer (BART) Code. III. Initialization, Atmospheric Profile Generator, Post-processing Routines
Cubillos, Patricio E.; Blecic, Jasmina; Challener, Ryan C. +12 more
This and companion papers by Harrington et al. and Cubillos et al. describe an open-source retrieval framework, Bayesian Atmospheric Radiative Transfer (BART), available to the community under the reproducible-research license via https://github.com/exosports/BART. BART is a radiative transfer code (transit; https://github.com/exosports/transit; R…
Mid-ultraviolet Hubble Observations of Europa and the Global Surface Distribution of SO2
Alday, Juan; Roth, Lorenz; McGrath, Melissa A. +6 more
We present spatially resolved reflectance spectra of Europa's surface in the wavelength range of 210-315 nm obtained by the Hubble Space Telescope Imaging Spectrograph in 2018 and 2019. These data provide the first high-quality, near-global spectral observations of Europa from 210 to 240 nm. They show that the reflectance of Europa's leading, trai…
Student Dust Counter Status Report: The First 50 au
Singer, Kelsi N.; James, David; Weaver, Harold +12 more
The Venetia Burney Student Dust Counter (SDC) is an in situ dust detector on board the New Horizons spacecraft measuring the interplanetary dust particle (IDP) distribution for grains with mass m > 10-12 g. SDC provides a near-continuous measure of the interplanetary dust environment, with recent results spanning beyond 50 au. This c…
The Diverse Shapes of Dwarf Planet and Large KBO Phase Curves Observed from New Horizons
Buratti, Bonnie J.; Singer, Kelsi N.; Stern, S. Alan +15 more
Observing dwarf planets and other large Kuiper Belt objects (KBOs) from vantage points between 8 and 47 au from the Sun, NASA's New Horizons spacecraft has found diversity in the shapes of their solar phase curves. Here we extend solar phase angle coverage of dwarf planets (136199) Eris, (136472) Makemake, and (136108) Haumea; large KBOs (28978) I…