Optical constants of Titan aerosols and their tholins analogs: Experimental results and modeling/observational data

Brassé, C.; Muñoz, Olga; Coll, Patrice; Raulin, F.

doi:10.1016/j.pss.2015.02.012

Cited by 43 publications

(58 citation statements)

References 62 publications

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“…Although the optical properties of a variety of tholins have been measured [ Podolak et al , ; Khare et al , ; Bar‐Nun et al , ; Coll et al , ; Ramírez et al , ; Tran et al , ; Bernard et al , ; Quirico et al , ; Vuitton et al , ; Hasenkopf et al , ; Gautier et al , ; Imanaka et al , ; Sciamma‐O'Brien et al , ; Mahjoub et al , ; Hadamcik et al , ], no laboratory analogue completely reproduces Titan's haze optical properties over the measured wavelength regions [ Tomasko et al , ; Bellucci et al , ; Lavvas et al , ; Rannou et al , ; Anderson and Samuelson , ; Kim et al , ; Vinatier et al , ; Hirtzig et al , ; Kim and Courtin , ; Sim et al , ; Courtin et al , ]. Brassé et al [] review the current state of optical constants for tholins. It is important to be aware that the optical constants of Khare et al [] are used most frequently because they are the only in depth study of optical constants for planetary haze particles that span a wide spectral range.…”

Section: Complex Organic Chemistrymentioning

confidence: 99%

Titan's atmosphere and climate

2017

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Titan is the only moon with a substantial atmosphere, the only other thick N2 atmosphere besides Earth's, the site of extraordinarily complex atmospheric chemistry that far surpasses any other solar system atmosphere, and the only other solar system body with stable liquid currently on its surface. The connection between Titan's surface and atmosphere is also unique in our solar system; atmospheric chemistry produces materials that are deposited on the surface and subsequently altered by surface‐atmosphere interactions such as aeolian and fluvial processes resulting in the formation of extensive dune fields and expansive lakes and seas. Titan's atmosphere is favorable for organic haze formation, which combined with the presence of some oxygen‐bearing molecules indicates that Titan's atmosphere may produce molecules of prebiotic interest. The combination of organics and liquid, in the form of water in a subsurface ocean and methane/ethane in the surface lakes and seas, means that Titan may be the ideal place in the solar system to test ideas about habitability, prebiotic chemistry, and the ubiquity and diversity of life in the universe. The Cassini‐Huygens mission to the Saturn system has provided a wealth of new information allowing for study of Titan as a complex system. Here I review our current understanding of Titan's atmosphere and climate forged from the powerful combination of Earth‐based observations, remote sensing and in situ spacecraft measurements, laboratory experiments, and models. I conclude with some of our remaining unanswered questions as the incredible era of exploration with Cassini‐Huygens comes to an end.

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Section: Complex Organic Chemistrymentioning

confidence: 99%

Titan's atmosphere and climate

2017

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“…They are thought to be present on the surfaces and/or in the atmospheres of several Solar System bodies. For example, they are likely responsible for the reddish color of many objects such as Pluto (Gladstone 2016) and Ceres (Combe et al 2017), and are believed to be responsible for Titan's atmospheric haze (Brassé et al 2015). Analysis of 1P/Halley dust mass spectra indicated for the first time the existence of CHON particles in comets (Kissel and Krueger 1987).…”

Section: Organicsmentioning

confidence: 99%

“…The refractive index of tholins at 532 nm has been reported by Hasenkopf et al (2010); for a detailed analysis of the tholins optical properties see Brassé et al (2015). The refractive indexes of the Allende, DaG521, FRO99040, and FRO95002 meteorite samples are unknown.…”

Section: Refractive Indexmentioning

confidence: 99%

Experimental phase function and degree of linear polarization of cometary dust analogues

Frattin

Muñoz

Moreno

et al. 2019

Monthly Notices of the Royal Astronomical Society

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We present experimental phase function and degree of linear polarization curves for seven samples of cometary dust analogues namely: ground pieces of Allende, DaG521, FRO95002 and FRO99040 meteorites, Mg-rich olivine and pyroxene, and a sample of organic tholins. The experimental curves have been obtained at the IAA Cosmic Dust Laboratory at a wavelength of 520 nm covering a phase angle range from 3 • to 175 • . We also provide values of the backscattering enhancement (BCE) for our cometary analogue samples. The final goal of this work is to compare our experimental curves with observational data of comets and asteroids to better constrain the nature of cometary and asteroidal dust grains. All measured phase functions present the typical behavior for µm-sized cosmic dust grains. Direct comparison with data provided by the OSIRIS/Rosetta camera for comet 67P Churyumov-Gerasimenko reveals significant differences and supports the idea of a coma dominated by big chunks, larger than one micrometer. The polarization curves are qualitatively similar to ground-based observations of comets and asteroids. The position of the inversion polarization angle seems to be dependent on the composition of the grains. We find opposite dependence of the maximum of the polarization curve for grains sizes in the Rayleigh-resonance and geometric optics domains, respectively.

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“…In our work, we computed the single scattering parameters for the tholin‐coated NH 3 cloud by using the BART code [ Quirantes and Delgado , ], which is based on the Aden‐Kerker theory, starting from the refractive index by Howett et al [] and Khare et al [] for ammonia ice and tholin, respectively. We tested different tholin refractive indexes covering the spectral region of interest as suggested in the work by Brassé et al []. The ones from Khare et al [] provided the best fit results on a sample of our data set.…”

Section: The Analysis Proceduresmentioning

confidence: 99%

Characterization of the white ovals on Jupiter's southern hemisphere using the first data by the Juno/JIRAM instrument

Sindoni

Grassi

Adriani

et al. 2017

Geophysical Research Letters

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During the first perijove passage of the Juno mission, the Jovian InfraRed Auroral Mapper (JIRAM) observed a line of closely spaced oval features in Jupiter's southern hemisphere, between 30°S and 45°S. In this work, we focused on the longitudinal region covering the three ovals having higher contrast at 5 μm, i.e., between 120°W and 60°W in System III coordinates. We used the JIRAM's full spectral capability in the range 2.4–3 μm together with a Bayesian data inversion approach to retrieve maps of column densities and altitudes for an NH3 cloud and an N2H4 haze. The deep (under the saturation level) volume mixing ratio and the relative humidity for gaseous ammonia were also retrieved. Our results suggest different vortex activity for the three ovals. Updraft and downdraft together with considerations about the ammonia condensation could explain our maps providing evidences of cyclonic and anticyclonic structures.

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Optical constants of Titan aerosols and their tholins analogs: Experimental results and modeling/observational data

Cited by 43 publications

References 62 publications

Titan's atmosphere and climate

Titan's atmosphere and climate

Experimental phase function and degree of linear polarization of cometary dust analogues

Characterization of the white ovals on Jupiter's southern hemisphere using the first data by the Juno/JIRAM instrument

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