Icy Worlds

Feasibility of Passive Sounding of Uranian Moons using Uranian Kilometric Radiation

By Keith Cowing
Press Release
May 9, 2023
Filed under , , , , , , ,
Feasibility of Passive Sounding of Uranian Moons using Uranian Kilometric Radiation
Frequency band available for passive sounding for each icy moon. The upper value of 900 kHz is due to the cutoff frequency of the UKR source. The green bar extends down to the plasma frequency upper limit derived from scaling to Europa’s peak ionospheric electron densities ( Figure 7) and scale heights. These upper limits are aggressively pessimistic given that, unlike Europa, Uranian icy moons do not reside in a plasma torus nor are they expected to be active. The yellow bars cover the uncertain range between the plasma frequency upper limit and the ambient plasma frequency in the Uranian system (f ‘ 9 kHz). Even with these pessimistic upper bounds, a significant portion of the spectrum of UKR emissions penetrate through the icy moon ionospheres and allows for passive sounding. — astro-ph.EP

We present a feasibility study for passive sounding of Uranian icy moons using Uranian Kilometric Radio (UKR) emissions in the 100 – 900 kHz band.

We provide a summary description of the observation geometry, the UKR characteristics, and estimate the sensitivity for an instrument analogous to the Cassini Radio Plasma Wave Science (RPWS) but with a modified receiver digitizer and signal processing chain.

We show that the concept has the potential to directly and unambiguously detect cold oceans within Uranian satellites and provide strong constraints on the interior structure in the presence of warm or no oceans. As part of a geophysical payload, the concept could therefore have a key role in the detection of oceans within the Uranian satellites.

The main limitation of the concept is coherence losses attributed to the extended source size of the UKR and dependence on the illumination geometry. These factors represent constraints on the tour design of a future Uranus mission in terms of flyby altitudes and encounter timing.

Andrew Romero-Wolf, Gregor Steinbruegge, Julie Castillo-Rogez, Corey J. Cochrane, Tom A. Nordheim, Karl L. Mitchell, Natalie S. Wolfenbarger, Dustin M. Schroeder, Sean T. Peters

Subjects: Earth and Planetary Astrophysics (astro-ph.EP); Instrumentation and Methods for Astrophysics (astro-ph.IM)
Cite as: arXiv:2305.05382 [astro-ph.EP] (or arXiv:2305.05382v1 [astro-ph.EP] for this version)
Submission history
From: Andrew Romero-Wolf
[v1] Sat, 6 May 2023 00:12:00 UTC (1,637 KB)

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