Titan in Late Northern Summer from JWST and Keck Observations
- 1NASA Goddard Space Flight Center, Planetary Systems Laboratory, Greenbelt, United States of America (conor.a.nixon@nasa.gov).
- 2LESIA, Observatoire de Paris, Université PSL, Sorbonne Université, Université Paris Cité, CNRS, Place Jules Janssen, Meudon, 92195, France.
- 3Aurora Technology BV for ESA, European Space Astronomy Centre (ESA/ESAC), Camino Bajo del Castillo s/n, Urb. Villafranca del Castillo, Villanueva de la Cañada, 28692, Spain
- 4Department of Geophysical Sciences, University of Chicago, 5734 S. Ellis Ave, Chicago, 60615, IL, USA
- 5Department of Astronomy and Department of Earth and Planetary Science, University of California, Berkeley, 501 Campbell Hall, University of California, Berkeley, 94720, USA.
- 6Université Paris Cité, Institut de physique du globe de Paris (IPGP), CNRS, Street, Paris, 75005, France.
- 7Association of Universities for Research in Astronomy, 1331 Pennsylvania Ave NW, Washington, 20004, DC, USA.
- 8Department of Earth and Planetary Sciences, Yale University, 210 Whitney Avenue, New Haven, 06511, CT, USA.
- 9Instituto de Astrofísica de Andalucía, CSIC, Glorieta de la Astronomía, s/n, Granada, E-18008, Spain.
- 10GSMA, UMR CNRS 7331, Université de Reims Champagne-Ardenne, Campus Sciences Exactes et Naturelles, Reims, 51687, France.
- 11School of Earth Sciences, University of Bristol, Queens Road, Bristol, BS8 1RJ, UK.
- 12Space Exploration Sector, Johns Hopkins Applied Physics Laboratory, 11100 Johns Hopkins Road, Laurel, 20723, MD, USA.
- *A full list of authors appears at the end of the abstract
Titan is an object of fascination for scientists researching the solar system, as a ‘terrestrial-like’ world with active meteorology and fluvial and lacustrine formations based on methane chemistry and condensation. The Cassini-Huygens mission explored Titan extensively from 2004 to 2017, but since that time further observation of its slow seasonal cycle has been possible only via telescopes positioned on or close to the Earth. Titan’s unique characteristics led to a concerted post-Cassini observational campaign, with many of the most powerful telescopes available to astronomy. In this work we report on observations from 2022 & 2023 with three instruments on the James Webb Space Telescope (JWST), NIRCam, NIRSpec and MIRI, also in coordination with imaging from Keck II. In November 2022 and July 2023, Titan was the subject of multi-spectral filter imaging with JWST NIRCam and Keck II NIRC2, revealing tropospheric clouds at mid-northern latitudes, in line with climate modeling predictions for this season (late northern summer). In filters sensitive to the upper troposphere, we observed clouds growing and apparently ascending in altitude during a Titan day. JWST NIRSpec spectroscopy yielded for the first time a high resolution (R=2700) spectrum of Titan across the entire near-infrared (1-5 microns) unobscured by telluric absorption. This, among other things, enabled measuring the detailed structure of the CO 4.7 micron non-LTE emission, including the fundamental, the first two overtone bands and two isotopic bands. It is also the first time that CO2 emission has been resolved in the NIR and the first time it has been seen on Titan’s dayside. Finally, very sensitive spectroscopy with JWST MIRI in the mid infrared (5-28 microns) confirmed the many stratospheric gases seen by Cassini CIRS, but also added a new detection of methyl (CH3) in the middle atmosphere, a product of methane photochemistry that was expected but not previously seen. We modeled parts of the spectra to find a global mean temperature profile and profiles of minor gases. Soon we hope to extract yet more results from the NIRSpec and MIRI spectra as our understanding of the calibration and modeling progresses. In this presentation we summarize our results to date and describe planned future observations of Titan with JWST and Keck cycles.
Richard K. Achterberg, Katherine de Kleer, Leigh N. Fletcher, Alexander G. Hayes, Bryan J. Holler, Patrick Irwin, Oliver R. King, Nicholas W. Kutsop, Stefanie N. Milam, Scot C. R. Rafkin, Michael T. Roman, Naomi Rowe-Gurney, Judy Schmidt, Christophe Sotin, John A. Stansberry, Robert A. West
How to cite: Nixon, C., Bézard, B., Cornet, T., Coy, B., de Pater, I., Es-Sayeh, M., Hammel, H., Lellouch, E., Lora, J., Lombardo, N., López-Puertas, M., Rannou, P., Rodriguez, S., Teanby, N., and Turtle, E. and the Titan JWST and Keck Observation Team: Titan in Late Northern Summer from JWST and Keck Observations, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-2392, https://doi.org/10.5194/egusphere-egu24-2392, 2024.
