Search Publications
Orbits and Masses of the Small Satellites of Pluto
Porter, Simon B.; Canup, Robin M.
We present a new orbit and mass solution for the four small satellites of Pluto: Styx, Nix, Kerberos, and Hydra. We have reanalyzed all available observations of the Pluto system obtained by the Hubble Space Telescope from 2005 to 2019 with the ACS, WFPC2, and WFC3 instruments, as well as the New Horizons LORRI images taken on approach to Pluto in…
Material around the Centaur (2060) Chiron from the 2018 November 28 UT Stellar Occultation
Bosh, Amanda S.; Person, Michael J.; Levine, Stephen E. +5 more
A stellar occultation of Gaia DR3 2646598228351156352 by the Centaur (2060) Chiron was observed from the South African Astronomical Observatory on 2018 November 28 UT. Here we present a positive detection of material surrounding Chiron from the 74-inch telescope for this event. Additionally, a global atmosphere is ruled out at the tens of microbar…
Effects of Airless Bodies' Regolith Structures and of the Solar Wind's Properties on the Backscattered Energetic Neutral Atoms Flux
Verkercke, S.; Chaufray, J. -Y.; Leblanc, F. +4 more
The surfaces of airless planetary bodies, such as the Moon or Mercury, are covered with regoliths, which interact with the solar wind. The solar protons can either be absorbed by the surface or neutralized and reflected as hydrogen energetic neutral atoms (ENAs). The ENA flux is thought to depend mostly on the structure of the upper regolith layer…
Detectability of the Yarkovsky Effect in the Main Belt
Tholen, David J.; Farnocchia, Davide; Hung, Denise +1 more
We attempt to detect a signal of Yarkovsky-related acceleration in the orbits of 134 main belt asteroids (MBAs) we observed with the University of Hawai'i 88 inch telescope, supplemented with observations publicly available from the Minor Planet Center and Gaia Data Release 3. We estimated the expected Yarkovsky acceleration values based on parame…
Implications for the Formation of (155140) 2005 UD from a New Convex Shape Model
Fedorets, Grigori; Granvik, Mikael; Kareta, Theodore +15 more
(155140) 2005 UD has a similar orbit to (3200) Phaethon, an active asteroid in a highly eccentric orbit thought to be the source of the Geminid meteor shower. Evidence points to a genetic relationship between these two objects, but we have yet to fully understand how 2005 UD and Phaethon could have separated into this associated pair. Presented he…
Maps of Solar Wind Plasma Precipitation onto Mercury's Surface: A Geographical Perspective
Henri, Pierre; Aizawa, Sae; Raines, Jim M. +7 more
Mercury is the closest planet to the Sun, possesses a weak intrinsic magnetic field, and has only a very tenuous atmosphere (exosphere). These three conditions result in a direct coupling between the plasma emitted from the Sun (namely, the solar wind) and Mercury's surface. The planet's magnetic field leads to a nontrivial pattern of plasma preci…
The Second International Asteroid Warning Network Timing Campaign: 2005 LW3
Licandro, Javier; Granvik, Mikael; Thuillot, William +90 more
The Earth close approach of near-Earth asteroid 2005 LW3 on 2022 November 23 represented a good opportunity for a second observing campaign to test the timing accuracy of astrometric observation. With 82 participating stations, the International Asteroid Warning Network collected 1046 observations of 2005 LW3 around the time of the close approach.…
The Influence of Cloud Condensation Nucleus Coagulation on the Venus Cloud Structure
Barth, Erika L.; McGouldrick, Kevin
We present the Venus version of PlanetCARMA and demonstrate the significance of coagulation properties on the structure of the Venus cloud system. The composition of the smallest mode of particles in the Venus atmosphere, which likely serve as cloud condensation nuclei (CCN), is unknown. Here we demonstrate that a change in the ability of CCN to g…
The Enigmatic Abundance of Atomic Hydrogen in Saturn's Upper Atmosphere
West, Robert A.; Ballester, Gilda E.; Moses, Julianne I. +5 more
A planet's Lyα emission is sensitive to its thermospheric structure. Here we report joint Hubble Space Telescope and Cassini cross-calibration observations of the Saturn Lyα emission made 2 weeks before the Cassini grand finale. To investigate the long-term Saturn Lyα airglow observed by different ultraviolet instruments, we cross-correlate their …
Temporal Evolution of Titan's Stratospheric Temperatures and Trace Gases from a Two-dimensional Retrieval of Cassini Composite Infrared Spectrometer Data
Achterberg, Richard K.
We use a two-dimensional (2D) radiative transfer model of Titan, which allows the atmospheric structure to vary in both altitude and latitude, to retrieve the spatial distribution of temperature, haze extinction, and C2H2, C2H6, C3H8, CH3C2H, C4H