We will assess the rotational variability in the stratospheres of the ice giants, Uranus and Neptune, to understand the dynamical and chemical variability of the atmospheric structure of both planets as a function of longitude. This effort follows up observations by the Spitzer IRS that shows consistent evidence for rotational variability of stratospheric hydrocarbons in Uranus and intermediate-term variability in Neptune.s emissions, neither of whose origins are not well understood. Herschel provides an opportunity to follow up these observations with its unparalleled sensitivity. Over the 17-hour periods characterizing the equatorial rotation periods of both planets a series of eight PACS dedicated line scans will be made of strategic lines of HD, methane and water vapor. An efficient scheme takes advantage of the simultaneous availability of Uranus and Neptune in Herschel.s visibility window. These will assess the variability of hydrocarbons vs temperatures in both atmospheres to an unprecedented accuracy. The results will be analyzed by a team consisting of many members of the Key Project on ..Water and Related Chemistry in the Solar System. who will apply their expertise with the data and its analysis, as well as researchers who discovered the Spitzer variability and ground-based inhomogeneity. The data will be examined in the context of models by team members who are experts in radiative transfer, photochemistry, and dynamical modeling of circulation and zonal thermal wave structure. By refining quantitative models for interactions between radiative, dynamical and chemical processes in these two cold but radiatively and dynamically diverse planets, a baseline will be created that will be useful in the interpretation of variability in the spectra of giant exoplanets. This work will also be programmatically useful in the evaluation of the variability of radiation from Uranus and Neptune, both which ar...e key members of the Herschel flux calibration system.
Publication
The D-H ratio in the atmospheres of Uranus and Neptune from Herschel-PACS observations . Feuchtgruber H. et al. . Astronomy & Astrophysics, Volume 551, id.A126, 9 pp. . 551 . 10.1051/0004-6361/201220857 . 2013A&A...551A.126F ,
Instrument
PACS_PacsLineSpec_point
Temporal Coverage
2011-01-12T11:21:14Z/2011-06-05T17:40:25Z
Version
SPG v14.2.0
Mission Description
Herschel was launched on 14 May 2009! It is the fourth 'cornerstone' mission in the ESA science programme. With a 3.5 m Cassegrain telescope it is the largest space telescope ever launched. It is performing photometry and spectroscopy in approximately the 55-671 µm range, bridging the gap between earlier infrared space missions and groundbased facilities.
