Overview of the coordinated ground‐based observations of Titan during the Huygens mission

Witasse, Olivier; Lebreton, Jean‐Pierre; Bird, M. K.; Dutta-Roy, R.; Folkner, W. M.; Preston, R. A.; Asmar, S. W.; Gurvits, L. I.; Pogrebenko, S. V.; Avruch, I. M.; Campbell, R. M.; Bignall, H. E.; Garrett, M. A.; Langevelde, H. J. van; Parsley, S. M.; Reynolds, C.; Szomoru, Arpad; Reynolds, John E.; Phillips, Chris; Sault, R. J.; Tzioumis, A. K.; Ghigo, F. D.; Langston, G. I.; Brisken, Walter; Romney, J. D.; Mujunen, Ari; Ritakari, Jouko; Tingay, S. J.; Dodson, Richard; Klooster, C.G.M. van 't; Blancquaert, Thierry; Coustenis, A.; Gendron, É.; Sicardy, B.; Hirtzig, M.; Luz, D.; Negrão, A.; Kostiuk, T.; Livengood, T. A.; Hartung, Markus; Pater, Imke de; Ádámkovics, Máté; Lorenz, Ralph D.; Roe, H. G.; Schaller, E. L.; Brown, Michael E.; Bouchez, Antonin H.; Trujillo, C. A.; Buratti, B. J.; Caillault, L.; Magin, Thierry; Bourdon, Anne; Laux, Christophe O.

doi:10.1029/2005je002640

Cited by 43 publications

(21 citation statements)

References 42 publications

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“…Ground-based observations of Jupiter's moon Io (Marchis et al, 2002) and Saturn's moon Titan (Witasse et al, 2006) have been found to be in good agreement with sizes measured from Galileo and Cassini spacecraft data.…”

Section: (2) Pallas Surface In the Near-infraredsupporting

confidence: 70%

Physical properties of (2) Pallas

Carry¹,

Dumas²,

Kaasalainen³

et al. 2010

Icarus

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a b s t r a c tGround-based high angular-resolution images of asteroid (2) Pallas at near-infrared wavelengths have been used to determine its physical properties (shape, dimensions, spatial orientation and albedo distribution).We acquired and analyzed adaptive optics (AO) J/H/K-band observations from Keck II and the Very Large Telescope taken during four Pallas oppositions between 2003 and 2007, with spatial resolution spanning 32-88 km (image scales 13-20 km/pixel). We improve our determination of the size, shape, and pole by a novel method that combines our AO data with 51 visual light-curves spanning 34 years of observations as well as archived occultation data.The shape model of Pallas derived here reproduces well both the projected shape of Pallas on the sky (average deviation of edge profile of 0.4 pixel) and light-curve behavior (average deviation of 0.019 mag) at all the epochs considered. We resolved the pole ambiguity and found the spin-vector coordinates to be within 5°of [longitude, latitude] = [30°, À16°] in the Ecliptic J2000.0 reference frame, indicating a high obliquity of about 84°, leading to high seasonal contrast. The best triaxial-ellipsoid fit returns ellipsoidal radii of a ¼ 275 km; b ¼ 258 km, and c ¼ 238 km. From the mass of Pallas determined by gravitational perturbation on other minor bodies ð1:2 AE 0:3Þ Â 10 À10 M , [Michalak, G., 2000. Astron. Astrophys. 360, 363-374], we derive a density of 3:4 AE 0:9 g cm À3 significantly different from the density of C-type (1) Ceres of 2:2 AE 0:1 g cm À3 [Carry, B., Dumas, C., Fulchignoni, M., Merline, W.J., Berthier, J., Hestroffer, D., Fusco, T., Tamblyn, P., 2008. Astron. Astrophys. 478 (4), 235-244]. Considering the spectral similarities of Pallas and Ceres at visible and near-infrared wavelengths, this may point to fundamental differences in the interior composition or structure of these two bodies.We define a planetocentric longitude system for Pallas, following IAU guidelines. We also present the first albedo maps of Pallas covering $80% of the surface in K-band. These maps reveal features with diameters in the 70-180 km range and an albedo contrast of about 6% with respect to the mean surface albedo.

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Section: (2) Pallas Surface In the Near-infraredsupporting

confidence: 70%

Physical properties of (2) Pallas

Carry¹,

Dumas²,

Kaasalainen³

et al. 2010

Icarus

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“…For example, our understanding of the Saturnian system is rapidly improving through the combination of different data sets from the Cassini-Huygens mission (e.g., Lebreton et al, 2005;Stofan et al, 2007;Witasse et al, 2006).…”

Section: Discussionmentioning

confidence: 99%

Planetary science: Multiple data sets, multiple scales, and unlocking the third dimension

Martin

Stofan²

2007

Geosphere

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Observations of the planets in our solar system cover a wide range of scales and are undertaken using a variety of techniques and platforms, resulting in extremely rich data sets. This review paper provides a basic introduction to the available range of planetary science data sets, and the combination of these data sets over a range of scales, resolutions, and techniques to address geological problems. The wealth of data available and the use of a selected combination of data sets to address geological problems are best illustrated by taking a closer look at the planet Mars. As a result of the increasing precision of spacecraft sensors, we now have data sets that cover the whole planet at spatial resolutions ranging from kilometers down to meters (e.g., Mars Global Surveyor) and multiple wavelengths (e.g., Mars Reconnaissance Orbiter), which have been collected over several years. This global coverage is complemented by surface missions that provide localized data sets down to microscopic resolutions (Mars Exploration Rovers). Thus, it is now possible to study geological features and processes quantitatively over an impressive range of scales. The combination of new data sets from current and future missions to Mars (e.g., Mars Express and Mars Reconnaissance Orbiter) will facilitate attempts to unlock the third dimension of Martian geology. The experience gained at Mars will help us to plan and exploit the 3-D exploration of other planets in the future.

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“…Previous studies for aerocapture trajectories with entry speeds between 6 and 10 km∕s highlighted uncertainties in the prediction of the peak radiative heat flux [2,3,7]. The peak radiative heat flux was significantly overpredicted by Boltzmann predictions, which were estimated to be as much as four times the peak convective heat flux.…”

Section: Introductionmentioning

confidence: 92%