Planetary Science Seminar - spring-2015

April 2, 2015
noon - 12:50 p.m.
Geology 4677

Presented By:

• Bruce G. Bills - JPL

The Cassini mission radar data have given an unprecedentedly accurate picture of the rotation of Titan. I will describe the data, and on-going efforts to model and understand the rotational variations.

In previous studies, it was claimed that Titan exhibits non-synchronous rotation. The current analysis clarifies that situation. There are small variations in the rate of rotation, but they are driven by variations in the orbit. Titan appears to be a synchronous rotator, in the sense of keeping its axis of least inertia oriented toward Saturn. The largest deviation from uniform rotation is at a period of 640 days, and is a response to variations in orbital mean longitude associated with the 4:3 mean motion resonance with Hyperion. This variation will presumably drive interesting motions within the fluid interior.

April 9, 2015
noon - 12:50 p.m.
Geology 4677

Presented By:

• William I. Newman - UCLA

Seminar Description coming soon.

April 16, 2015
noon - 12:50 p.m.
Geology 4677

Presented By:

• Bonnie J. Buratti - JPL

Seminar Description coming soon.

April 23, 2015
noon - 12:50 p.m.
Geology 4677

Presented By:

• Joseph Masiero - JPL

Seminar Description coming soon.

April 30, 2015
noon - 12:50 p.m.
Geology 4677

Presented By:

• Glenn S. Orton - JPL

Similar to Earth-observing weather satellites, mid-infrared observations of the outer planets are sensitive to the distribution of temperatures, minor and trace gaseous constituents and the distribution of clouds and aerosols. Key sets of observations can be used with both spectroscopy and imaging of thermal emission to derive these properties. Recent observations with sensitive instrumentation on the Spitzer and Herschel infrared telescopes are providing access to new spectral regions. Sensitive ground-based spatially resolved observations, such as those from the Infrared Telescope Facility, the Very Large Telescope, the Gemini Telescopes, and the Subaru Telescope are extending observations by the Voyager IRIS experiment from several decades ago both to determine variability in time and to uncover additional information in fainter spectral regions that were not within the grasp of Voyager. Recent examples include the discovery of non-seasonal as well as seasonal dependence of temperatures in Saturn and Jupiter that indicate the presence of waves with properties that are similar to those in the Earth's atmosphere. We plan to focus ground-based observations in a campaign to supplement observations from the Juno mission that is scheduled to orbit Jupiter in the 2016-2018 time frame.

May 21, 2015
noon - 12:50 p.m.
Geology 4677

Presented By:

• Deborah S. Bass - JPL

Building on the success of Curiosity's landing, NASA announced plans for a new robotic science rover set to launch in 2020, based on the Curiosity design. The proposed 2020 rover mission is part of NASA's Mars Exploration Program , a long-term effort of robotic exploration of the red planet. Designed to advance high-priority science goals for Mars exploration, the mission would address key questions about the potential habitability of the rover’s landing site and directly search for signs of ancient life on Mars. The mission would also provide opportunities to gather knowledge and demonstrate technologies that address the challenges of future human expeditions to Mars. Dr. Bass will speak with us on this exciting new chapter of Mars exploration.

May 28, 2015
noon - 12:50 p.m.
Geology 4677

Presented By:

• James Sinclair - JPL

Saturn has an axial tilt of 26.7deg and therefore experiences seasons during it’s 29.5 year orbital period around the Sun. CIRS (Composite Infrared Spectrometer) observations from the Cassini spacecraft acquired from 2004 (upon arrival to Saturn) to present cover approximately a Saturnian season and have allowed the effects of seasonal change on Saturn’s temperature and composition to be tracked. In addition, CIRS data acquired in 2009/2010 captures Saturn approximately one Saturnian year after the Voyager flybys in 1980/1981 during which IRIS (Infrared Interferometer Spectrometer) observations were acquired. A comparison of atmospheric properties from IRIS and CIRS therefore allows internannual variability to be explored. An retrieval analysis of Cassini-CIRS and Voyager-IRIS observations has been conducted in order to investigate the seasonal and interannual variability of Saturn’s stratosphere.

June 4, 2015
noon - 12:50 p.m.
Geology 4677

Presented By:

• Richard M. Thorne - UCLA

On July 5 , 2016 after a five year cruise, JUNO will be inserted into orbit around Jupiter. Jupiter is by far the largest planet in our solar system and has remained virtually unchanged since it first formed. Consequently, Jupiter contains important clues to how the solar system formed. The primary science objective of this second NASA "New Frontiers” mission is to measure the Oxygen (Water) abundance in the deep atmosphere, to determine whether Jupiter has a substantial core composed of heavy elements, and to understand the dynamo process which generates Jupiters’s internal magnetic field. To accomplish these objectives JUNO will be placed into a polar orbit, which minimizes radiation exposure and allows, us over 30 science orbits, to make precise measurements of the internal gravity and magnetic field, and the composition of the deep atmosphere. These science orbits pass through the auroral flux tubes and as a secondary science objective we will explore the process responsible for the Jovian aurora. This talk will describe the basic measurements taken on JUNO and describe how these can be used to better understand the process that occurred during the formation of the solar system.