DETECTION AND TRACKING OF SUBTLE CLOUD FEATURES ON URANUS

Journal Article · Fri Jun 15 04:00:00 EDT 2012 · Astronomical Journal (New York, N.Y. Online)

DOI:https://doi.org/10.1088/0004-6256/143/6/150· OSTI ID:22034442

Fry, P M; Sromovsky, L A ^[1]; De Pater, I ^[2]; Hammel, H B ^[3]

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1. Space Science and Engineering Center, University of Wisconsin, Madison, WI 53706 (United States)
2. Astronomy Department, University of California, Berkeley, CA 94720 (United States)
3. Association of Universities for Research in Astronomy, Washington, DC 20005 (United States)

The recently updated Uranus zonal wind profile (Sromovsky et al.) samples latitudes from 71 Degree-Sign S to 73 Degree-Sign N. But many latitudes remain grossly undersampled (outside 20 Degree-Sign -45 Degree-Sign S and 20 Degree-Sign -50 Degree-Sign N) due to a lack of trackable cloud features. Offering some hope of filling these gaps is our recent discovery of low-contrast cloud that can be revealed by imaging at much higher signal-to-noise ratios (S/Ns) than previously obtained. This is demonstrated using an average of 2007 Keck II NIRC2 near-IR observations. Eleven one-minute H-band exposures, acquired over a 1.6 hr time span, were rectilinearly remapped and zonally shifted to account for planetary rotation. This increased the S/N by about a factor of 3.3. A new fine structure in latitude bands appeared, small previously unobservable cloud tracers became discernible, and some faint cloud features became prominent. While we could produce one such high-quality average, we could not produce enough to actually track the newly revealed features. This requires a specially designed observational effort. We have designed recent Hubble Space Telescope WFC3 F845M observations to allow application of the technique. We measured eight zonal winds by tracking features in these images and found that several fall off of the current zonal wind profile of Sromovsky et al., and are consistent with a partial reversal of their hemispherically asymmetric profile.

• OSTI ID: 22034442
• Journal Information: Astronomical Journal (New York, N.Y. Online), Journal Name: Astronomical Journal (New York, N.Y. Online) Journal Issue: 6 Vol. 143; ISSN 1538-3881
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
ASTRONOMY
ASTROPHYSICS
CLOUDS
DETECTION
FINE STRUCTURE
IMAGE PROCESSING
NEAR INFRARED RADIATION
SATELLITE ATMOSPHERES
SATELLITES
SIGNAL-TO-NOISE RATIO
SPACE
TELESCOPES
URANUS PLANET
WIND