ALBERT

Description: Although the primary focus of the Jupiter Icy Moons Orbiter (JIMO) mission will be the characterization and study of Jupiter's icy moons, there will be opportunities throughout the mission for unprecendented observations of Jupiter. With an adaptable suite of payload instruments, the atmospheric data collected by JIMO can help to answer fundamental questions about the largest planet in our solar system that remain after (or were generated by) previous spacecraft reconnaissance (e.g. Voyager, Galileo, and Cassini). Near-IR (0.7-4 micron) spectral imaging will most likely be used to identify mineralogies and ices on the Jovian satellites by virtue of their spectral signatures. This same capability is very well tailored for studies of Jovian atmospheric dynamics and structure. Near-IR methane absorption bands allow 2-D mapping of the horizontal wind field at size scales to tens of kms, as well as the height dependence of this field above the ammonia cloud deck (700 to a few mbar), constraining current models of atmospheric vertical structure. Likewise, atmospheric ice aerosols with unique spectroscopic signatures (ammonia ice near 1.5, 2.0, and 2.8 microns and water ice between 3.0 - 3.5 microns) can be detected and mapped using spectral difference imaging or spectrally inclusive principal-component methods. Spectral imaging of the Jovian aurora via (3)H(+) emission lines between 3 - 4 microns can be used to spatially map the interplay between the satellites) Jupiter's magnetosphere, and Jupiter's atmosphere. Each of these measurements addresses one or more fundamental questions related to the energy balance in Jupiter's atmosphere. All of these tunable imaging objectives can be achieved using acousto-optic tunable filters (AOTF's), which have been used for years in ground-based observing instruments and which have been proposed for numerous planetary missions. The application of this technology to the science objectives of both the icy satellites and Jovian atmospheric components of the JIMO mission will be discussed.

Description: Submillimeter emission lines of carbon monoxide (CO) in Titan's atmosphere provide excellent probes of atmospheric temperature due to the molecule's long chemical lifetime and stable, well constrained volume mixing ratio. Here we present the analysis of 4 datasets obtained with the Atacama Large Millimeter/Submillimeter Array (ALMA) in 2012, 2013, 2014, and 2015 that contain strong CO rotational transitions. Utilizing ALMA's high spatial resolution in the 2012, 2014, and 2015 observations, we extract spectra from 3 separate regions on Titan's disk using datasets with beam sizes ranging from 0.35 0.28'' to 0.39 0.34''. Temperature profiles retrieved by the NEMESIS radiative transfer code are compared to Cassini Composite Infrared Spectrometer (CIRS) and radio occultation science results from similar latitude regions. Disk-averaged temperature profiles stay relatively constant from year to year, while small seasonal variations in atmospheric temperature are present from 2012 to 2015 in the stratosphere and mesosphere ( approx. 100-500 km) of spatially resolved regions. We measure the stratopause (320 km) to in- crease in temperature by 5 K in northern latitudes from 2012 to 2015, while temperatures rise throughout the stratosphere at lower latitudes. We observe generally cooler temperatures in the lower stratosphere ( approx. 100 km) than those obtained through Cassini radio occultation measurements, with the notable exception of warming in the northern latitudes and the absence of previous instabilities; both of these results are indicators that Titan's lower atmosphere responds to seasonal effects, particularly at higher latitudes. While retrieved temperature profiles cover a range of latitudes in these observations, deviations from CIRS nadir maps and radio occultation measurements convolved with the ALMA beam-footprint are not found to be statistically significant, and discrepancies are often found to be less than 5 K throughout the atmosphere. ALMA's excellent sensitivity in the lower stratosphere (60-300 km) provides a highly complementary dataset to contemporary CIRS and radio science observations, including altitude regions where both of those measurement sets contain large uncertainties. The demonstrated utility of CO emission lines in the submillimeter as a tracer of Titan's atmospheric temperature lays the groundwork for future studies of other molecular species -particularly those that exhibit strong polar abundance enhancements or are pressure-broadened in the lower atmosphere, as temperature profiles are found to consistently vary with latitude in all three years by up to 15 K.

Description: Hubble Space Telescope data of the passage of Jupiter's Great Red Spot (GRS) and Oval BA were acquired on May 15, June 28 (near closest approach), and July 8. Wind fields were measured from Wide Field Planetary Camera 2 (WFPC2) data with 10-hour separations before and after closest approach, and within the GRS with 40-minute separations on all three dates. Color information was also derived using 8 narrowband WFPC2 filters from 343 to 673-nm on all three dates. We will present the results of principal components and wind analyses and discuss unique features seen in this data set. In addition, we will highlight any changes observed in the GRS, Oval BA and their surroundings as a result of the passage, including the movement of a smaller red anticyclone from west of the GRS, around its southern periphery, and to the east of the GRS.

Description: In recent years, Jupiter has undergone many atmospheric changes from storms turning red to global. cloud upheavals, and most recently, a cornet or asteroid impact. Yet, on top of these seemingly random changes events there are also periodic phenomena, analogous to observed Earth and Saturn atmospheric oscillations. We will present 15 years of Hubble data, from 1994 to 2009, to show how the equatorial tropospheric cloud deck and winds have varied over that time, focusing on the F953N, F41 ON and F255W filters. These filters give leverage on wind speeds plus cloud opacity, cloud height and tropospheric haze thickness, and stratospheric haze, respectively. The wind data consistently show a periodic oscillation near 7-8 S latitude. We will discuss the potential for variations with longitude and cloud height, within the calibration limits of those filters. Finally, we will discuss the role that large atmospheric events, such as the impacts in 1994 and 2009, and the global upheaval of 2007, have on temporal studies, This work was supported by a grant from the NASA Planetary Atmospheres Program. HST observational support was provided by NASA through grants from Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under contract NAS5-26555.