Search Publications
The two Titan stellar occultations of 14 November 2003
Glass, I. S.; Jones, T.; Colas, F. +49 more
We report the observation of two stellar occultations by Titan on 14 November 2003, using stations in the Indian Ocean, southern Africa, Spain, and northern and southern Americas. These occultations probed altitudes between ~550 and 250 km (~1 to 250 µbar) in Titan's upper stratosphere. The light curves reveal a sharp inversion layer near 51…
Winds on Titan from ground-based tracking of the Huygens probe
Plettemeier, D.; Bird, M. K.; Asmar, S. W. +14 more
Large radio telescopes on Earth tracked the radio signal transmitted by the Huygens probe during its mission at Titan. Frequency measurements were conducted as a part of the Huygens Doppler Wind Experiment (DWE) in order to derive the velocity of the probe in the direction to Earth. The DWE instrumentation on board Huygens consisted of an ultrasta…
Titan's planetary boundary layer structure at the Huygens landing site
Colombatti, Giacomo; Tokano, Tetsuya; Ferri, Francesca +2 more
Huygens Atmospheric Structure Instrument (HASI) for the first time performed an in situ measurement of the thermal structure in Titan's atmosphere with a vertical resolution sufficient to analyze the planetary boundary layer (PBL). The vertical potential temperature profile reveals the presence of a weakly convective PBL, with a surface layer thic…
Overview of the coordinated ground-based observations of Titan during the Huygens mission
de Pater, Imke; Sicardy, Bruno; Buratti, Bonnie J. +50 more
Coordinated ground-based observations of Titan were performed around or during the Huygens atmospheric probe mission at Titan on 14 January 2005, connecting the momentary in situ observations by the probe with the synoptic coverage provided by continuing ground-based programs. These observations consisted of three different categories: (1) radio t…
Characterization of zonal winds in the stratosphere of Titan with UVES: 2. Observations coordinated with the Huygens Probe entry
Livengood, T.; Kostiuk, T.; Witasse, O. +8 more
The Huygens Probe has successfully entered Titan's atmosphere and landed on its surface on 14 January 2005. With the aim of characterizing the zonal wind flow in Titan's stratosphere close to the time of entry, coordinated observations were carried out at the Very Large Telescope on the nights of 7, 12, 14, and 15 January. As in our previous inves…
Stratospheric global winds on Titan at the time of Huygens descent
Sonnabend, G.; Kostiuk, T.; Witasse, O. +9 more
Measurements of stratospheric zonal winds on Titan were made in preparation for and during the time of the descent of the Huygens Probe into Titan's atmosphere on 14 January 2005. Fully resolved emission lines from ethane near 11.7 µm were measured on the east, center, and west positions on Titan using the NASA/GSFC Heterodyne Instrument for…
Titan's bright spots: Multiband spectroscopic measurement of surface diversity and hazes
Genzel, R.; Eisenhauer, F.; de Pater, I. +3 more
Spatially resolved near-infrared spectra of Titan, which simultaneously cover two CH4 absorption bands (from 1.45 to 2.45 µm), have been obtained using the SINFONI integral-field spectrometer with adaptive optics at the Very Large Telescope (VLT) of the European Southern Observatory. We observe the enhancement in 2 µm surfac…
Nonequilibrium radiative heat flux modeling for the Huygens entry probe
Magin, T. E.; Caillault, L.; Bourdon, A. +1 more
An electronic collisional-radiative model is proposed to predict the nonequilibrium populations and the radiation of the excited electronic states CN(A, B) and N2(A, B, C) during the entry of the Huygens probe into the atmosphere of Titan. The model is loosely coupled with flow solvers using a Lagrangian method. First, the model was tes…
Titan imagery with Keck adaptive optics during and after probe entry
de Pater, Imke; Brown, Michael E.; Marchis, Franck +6 more
We present adaptive optics data from the Keck telescope, taken while the Huygens probe descended through Titan's atmosphere and on the days following touchdown. No probe entry signal was detected. Our observations span a solar phase angle range from 0.05° up to 0.8°, with the Sun in the west. Contrary to expectations, the east side of Titan's stra…
Limits to the abundance of surface CO2 ice on Titan
Coustenis, A.; Dumas, C.; Hartung, M. +1 more
In the context of the Cassini/Huygens mission, we performed supporting ground-based observations to complement the results from the NASA/ESA/ASI space mission to the Saturnian system with particular focus on Titan. On the nights of 18 and 19 December 2004, we conducted adaptive optics observations with VLT/NACO to search for and map the distributi…