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| Paper: |
Exploring Solar System Giant Planets with Habitable Worlds Observatory |
| Monograph: |
10, HWO25 Proceedings Part I: Community Science Case Development Documents |
| Page: |
575 |
| Authors: |
Leigh N. Fletcher; Amy Simon; Michael H. Wong; Jonathan D. Nichols; Nick A. Teanby; Conor A. Nixon; Marina Galand |
| DOI: |
10.26624/EEFC7595 |
| Abstract: |
Visible and ultraviolet imaging and spectroscopy of Solar System giant planets can set the paradigm
for the atmospheric, ionospheric, and magnetospheric processes shaping the diversity of giant exoplanets,
brown dwarfs, and their interactions with stellar hosts. Spectra of their molecular absorptions, aerosol
scattering, airglow, and auroral emissions can reveal these dynamic atmospheres in three dimensions, from
the cloud-forming weather layer, to the ionosphere and beyond. Given that giant planets are extended, bright,
moving, and rotating objects, with extreme dynamic range and highly variable appearances, they impose
specific mission and instrumentation requirements on future large space-based optical/UV observatories like
the proposed Habitable Worlds Observatory (HWO). We advocate that HWO must have the capability to track
non-sidereal targets like the giant planets and their satellites; should be able to view auroras and atmospheres
without saturation (e.g., through the use of filters or fast read-out modes); and with a high dynamic range to
explore faint objects near bright discs. HWO should enable spatially-resolved spectroscopy from ∼80 nm to
∼900 nm, capturing H2 Lyman and Werner band series and H Lyman-α in the far-UV; molecular absorptions
and scattering in the mid-UV/visible; and deep hydrogen/methane absorptions in the 800-900 nm for cloud
characterisation and CH4 mapping. Imaging should enable time-resolved observations, from seconds to
create auroral movies, to hours for cloud tracking and winds, to months and years for atmosphere/ionosphere
variability. We advocate that an imager should have sufficient field of view to capture Jupiter (> 50′′), and
that UV/visible integral field spectrographs be considered with both narrow (3′′) and wide (> 10′′) field
capabilities to provide efficient mapping of atmospheres and auroras. A large field of regard would enable
viewing giant planets over a full apparition, enabling rapid viewing of unexpected phenomena (impacts,
storms, solar events, etc.), and maximal spatial resolution at opposition. The benefits of extension beyond
1 µm are also discussed. With these capabilities, HWO would enable new discoveries in comparative
planetology, from our Solar System giants to those in other stellar systems.
This article is an adaptation of a
science case document developed for HWO’s Solar System Steering Committee. |
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