Search Publications
Observation of DCl and upper limit to NH3 on Venus
Krasnopolsky, Vladimir
To search for DCl in the Venus atmosphere, a spectrum near the D35Cl (1-0) R4 line at 2141.54 cm-1 was observed using the CSHELL spectrograph at NASA IRTF. Least square fitting to the spectrum by a synthetic spectrum results in a DCl mixing ratio of 17.8 ± 6.8 ppb. Comparing to the HCl abundance of 400 ± 30 ppb (Krasnopolsky …
Zonal winds at high latitudes on Venus: An improved application of cyclostrophic balance to Venus Express observations
Read, Peter L.; Mendonça, João M.; Wilson, Colin F. +1 more
Recent retrievals of zonal thermal winds obtained in a cyclostrophic regime on Venus are generally consistent with cloud tracking measurements at mid-latitudes, but become unphysical in polar regions where the values obtained above the clouds are often less than or close to zero. Using a global atmospheric model, we show that the main source of er…
UV spectrum of Enceladus
Noll, Keith S.; Clarke, John T.; Hendrix, Amanda R. +1 more
We present a far ultraviolet (FUV) spectrum of Saturn’s moon Enceladus from the Cosmic Origins Spectrograph (COS) on the Hubble Space Telescope (HST). We have put upper limits on emission from C, N, and O lines in Enceladus’ atmosphere and column densities for the C lines assuming solar resonance scattering. We find these upper limits to be relati…
Improved luminosity model and albedo for Saturn
Mallama, Anthony
The globe of Saturn is brighter than previously reported as indicated by its absolute opposition magnitudes in the UBVRI band passes which are -7.080, -7.842, -8.914, -9.587 and -9.606, respectively. The geometric albedo in V is 0.501 and it peaks in the R filter at 0.567. The brightest apparent magnitude of the system in the V-band is -0.61 and t…
Vertical cloud structure of the 2009 Jupiter impact based on HST/WFC3 observations
Sánchez-Lavega, A.; Pérez-Hoyos, S.; Wong, M. H. +7 more
The impact of a body of unknown origin with Jupiter in July 2009 produced an intense perturbation of the planet’s atmosphere at the visible cloud levels. The vertical cloud structure was deeply affected by the presence of a strongly absorbing dense aerosol layer that was expanded steadily by advection in the local winds. We observed this phenomeno…
Comparisons of Cassini flybys of the Titan magnetospheric interaction with an MHD model: Evidence for organized behavior at high altitudes
Luhmann, J. G.; Russell, C. T.; Dougherty, M. K. +8 more
Recent papers suggest the significant variability of conditions in Saturn's magnetosphere at the orbit of Titan. Because of this variability, it was expected that models would generally have a difficult time regularly comparing to data from the Titan flybys. However, we find that in contrast to this expectation, it appears that there is underlying…
Thermal convection in the porous methane-soaked regolith in Titan: Finite amplitude convection
Czechowski, Leszek; Kossacki, Konrad J.
Titan is the only body, beside the Earth, where liquid is present on the surface. This paper is aimed to show the properties of possible convection in a porous regolith on Titan. In our previous work (Czechowski, L., Kossacki, K.J. [2009]. Icarus 202, 599-607) we showed, that the Rayleigh number Ra can exceed its critical value Rac. Hen…
CO prompt emission as a CO2 marker in comets and planetary atmospheres
Slanger, Tom G.; Kalogerakis, Konstantinos S.; Ahmed, Musahid +2 more
Observations of CO emissions in the visible and near-infrared (NIR) have been rare for comets, and no measurements from orbiters are currently available in the visible for the dayglows of Mars or Venus. Analysis of the ultraviolet CO(a-X) Cameron bands from Mars Express dayglow observations supports the conclusion that these bands have very high r…
Aerial electromagnetic sounding of the lithosphere of Venus
Harrison, Keith P.; Barr, Amy C.; Grimm, Robert E. +4 more
Electromagnetic (EM) investigation depths are larger on Venus than Earth due to the dearth of water in rocks, in spite of higher temperatures. Whistlers detected by Venus Express proved that lightning is present, so the Schumann resonances ∼10-40 Hz may provide a global source of electromagnetic energy that penetrates ∼10-100 km. Electrical conduc…
Upper limits on the size of satellites of Asteroid (4) Vesta from 2007 Hubble Space Telescope observations
Mutchler, Max; Hamilton, Douglas P.; Li, Jian-Yang +4 more
We imaged the region around Asteroid (4) Vesta in nine long exposures using the Wide Field Planetary Camera 2 on the Hubble Space Telescope on May 14 and 16, 2007 to conduct a deep search for satellites in support of NASA's Dawn mission that orbited (4) Vesta in 2011-2012. Several previous search efforts have been undertaken, but no satellites wer…