Search Publications
Emerging trends and a comet taxonomy based on the volatile chemistry measured in thirty comets with high-resolution infrared spectroscopy between 1997 and 2013
Weaver, Harold A.; Vervack, Ronald J.; Kawakita, Hideyo +1 more
A systematic analysis of the mixing ratios with respect to H2O for eight species (CH3OH, HCN, NH3, H2CO, C2H2, C2H6, CH4, and CO) measured with high-resolution infrared spectroscopy in thirty comets between 1997 and 2013 is presented. Some trends are…
Daily global mapping of Mars ozone column abundances with MARCI UV band imaging
Smith, Michael D.; Wolff, Michael J.; Lefèvre, Franck +3 more
Since November of 2006, The Mars Color Imager (MARCI) onboard the Mars Reconnaissance Orbiter (MRO) has obtained multiple-filter daily global images of Mars centered upon a local time (LT) of 3 pm. Ultraviolet imaging bands placed within (260 nm) and longward (320 nm) of Hartley band (240-300 nm) ozone (O3) absorption support retrievals…
Chromophores from photolyzed ammonia reacting with acetylene: Application to Jupiter's Great Red Spot
Baines, K. H.; Carlson, R. W.; Simon, A. A. +2 more
The high altitude of Jupiter's Great Red Spot (GRS) may enhance the upward flux of gaseous ammonia (NH3) into the high troposphere, where NH3 molecules can be photodissociated and initiate a chain of chemical reactions with downwelling acetylene molecules (C2H2). These reactions, experimentally studied e…
Discrete sources of cryovolcanism on the nucleus of Comet 29P/Schwassmann-Wachmann and their origin
Miles, Richard
Evidence for long-lived sources of cryovolcanism on the nucleus of the Comet 29P/Schwassmann-Wachmann has been found from a study of its times of outburst (t0) and the morphological development of inner coma structures. Analysis of data from the Minor Planet Center observations archive spanning 2002-2014 and other observations have yiel…
Characteristics of north jovian aurora from STIS FUV spectral images
Bonfond, B.; Nichols, J. D.; Ray, L. C. +4 more
We analyzed two observations obtained in Jan. 2013, consisting of spatial scans of the jovian north ultraviolet aurora with the HST Space Telescope Imaging Spectrograph (STIS) in the spectroscopic mode. The color ratio (CR) method, which relates the wavelength-dependent absorption of the FUV spectra to the mean energy of the precipitating electron…
Anatomy of outbursts and quiescent activity of Comet 29P/Schwassmann-Wachmann
Roche, Paul; Mottola, Stefano; Miles, Richard +4 more
Detailed morphological and photometric characterisation of Comet 29P in the optical region is presented comprising: (a) multi-filter observations of the outburst coma in 2010-2012 with the 2.0-m Faulkes Telescopes (FT); (b) high-cadence, high-precision photometry in May-September 2014; and (c) HST observations in March 1996 (WFPC2/F702W filter). O…
Saturn's auroral morphology and field-aligned currents during a solar wind compression
Brown, R. H.; Baines, K. H.; Dougherty, M. K. +12 more
On 21-22 April 2013, during a coordinated auroral observing campaign, instruments onboard Cassini and the Hubble Space Telescope observed Saturn's aurora while Cassini traversed Saturn's high latitude auroral field lines. Signatures of upward and downward field-aligned currents were detected in the nightside magnetosphere in the magnetic field and…
The spectrum of Jupiter's Great Red Spot: The case for ammonium hydrosulfide (NH4SH)
Chanover, Nancy J.; Simon, Amy A.; Hudson, Reggie L. +1 more
Here we present new ultraviolet-visible spectra of irradiated ammonium hydrosulfide (NH4SH), a reported jovian atmospheric cloud component, for a range of temperatures and radiation doses and make assignments to the spectral features. We show that the combination of radiolysis and thermal annealing of NH4SH causes the origina…
Saturn's northern auroras as observed using the Hubble Space Telescope
Badman, S. V.; Nichols, J. D.; Clarke, J. T. +4 more
We discuss the features of Saturn's northern FUV auroras as observed during a program of Hubble Space Telescope observations which executed over 2011-2013 and culminated, along with Cassini observations, in a comprehensive multi-spectral observing campaign. Our 2011-2013 observations of the northern aurora are also compared with those from our 200…
DSMC simulation of Europa water vapor plumes
Trafton, L. M.; Berg, J. J.; Goldstein, D. B. +1 more
A computational investigation of the physics of water vapor plumes on Europa was performed with a focus on characteristics relevant to observation and spacecraft mission operations. The direct simulation Monte Carlo (DSMC) method was used to model the plume expansion assuming a supersonic vent source. The structure of the plume was determined, inc…