Events

June 21, 2022 11:00 - 12:00 EDT

Ice Giant Systems Seminar Series: Dr. Jason Hofgartner

Zoom

*** Delayed one week from the usual "2nd Tuesday" date to deconflict with the OPAG Meeting. ***
Presenter: Dr. Jason Hofgartner (Cornell University)
Topic: Hypotheses for Triton's Plumes: New Analyses and Future Remote Sensing Tests
Abstract: At least two active plumes were observed on Triton during the Voyager 2 flyby in 1989. An eruption model based on a solar-powered, solid-state greenhouse effect was previously considered the leading hypothesis for Triton's plumes, in part due to the proximity of the plumes to the subsolar latitude during the Voyager 2 flyby and the distribution of Triton's fans that are putatively deposits from former plumes. Based on new analyses of the ostensible relation between the latitude of the subsolar point on Triton and the geographic locations of the plumes and fans, we argue that neither the locations of the plumes nor fans are strong evidence in favor of the solar-powered hypothesis. We conclude that two other eruption models based on internal heat, not solar insolation, as well as the solar-powered greenhouse model should be further considered. We present five tests that could be implemented with remote sensing observations from future spacecraft to confidently distinguish among the eruption hypotheses for Triton's plumes.

Questions? jodi.berdis@jhuapl.edu

August 9, 2022 11:00 - 12:00 EDT

Ice Giant Systems Seminar Series: Dr. Naomi Rowe-Gurney

Zoom

Presenter: Dr. Naomi Rowe-Gurney (NASA Goddard)
Topic: Neptune's Atmospheric Structure from the Spitzer Infrared Spectrometer
Abstract: NASA's Spitzer Infrared Spectrometer (IRS) acquired mid-infrared (5 - 37 micron) disc-averaged spectra of Neptune multiple times between 2004 and 2006. The data from 2005 is analysed using optimal estimation retrievals for the first time. The disc-averaged thermal and chemical structure from Spitzer will likely be our best characterisation of Neptune's thermal structure until JWST/MIRI acquires spatially resolved mid-infrared spectroscopy in the next year.

Questions? jodi.berdis@jhuapl.edu

September 13, 2022 11:00 - 12:00 EDT

Ice Giant Systems Seminar Series: Dr. Amy Simon

Zoom

Presenter: Dr. Amy Simon (NASA Goddard)
Topic: Observing Neptune's Great Dark Spots
Abstract: Neptune's iconic Great Dark Spot, seen by Voyager 2 in 1989, had disappeared before the first Hubble Space Telescope observations in 1995. However, several new dark spots have been observed from 1995 to 2022. This talk will discuss their behavior and longevity as observed by Hubble.

Questions? jodi.berdis@jhuapl.edu

October 11, 2022 11:00 - 12:00 EDT

Ice Giant Systems Seminar Series: Dr. Tanguy Bertrand

Zoom

Presenter: Dr. Tanguy Bertrand (LESIA, Paris Observatory)
Topic: Volatile Transport and Climate Modeling on Triton
Abstract: We developed a Volatile Transport Model (VTM) and a Global Climate Model (GCM) of Triton and tested its ability to simulate its volatile cycles of N2, CH4 and CO as well as the dynamics of its atmosphere. We will present results published in a recent paper (Bertrand et al., 2022) showing how the volatile cycles evolve over long-term and seasonal timescales for varying model parameters, and what scenarios allow for a best match of the available observations. We will also present results regarding the atmosphere dynamics of Triton. Finally, we will discuss the implications of these results and how future observations could help us better understand how Triton works.

Questions? jodi.berdis@jhuapl.edu