The Process of Tholin Formation in Titan's Upper Atmosphere

  title={The Process of Tholin Formation in Titan's Upper Atmosphere},
  author={J. Waite and D. Young and T. Cravens and A. Coates and F. Crary and B. Magee and J. Westlake},
  pages={870 - 875}
Titan's lower atmosphere has long been known to harbor organic aerosols (tholins) presumed to have been formed from simple molecules, such as methane and nitrogen (CH4 and N2). Up to now, it has been assumed that tholins were formed at altitudes of several hundred kilometers by processes as yet unobserved. Using measurements from a combination of mass/charge and energy/charge spectrometers on the Cassini spacecraft, we have obtained evidence for tholin formation at high altitudes (∼1000… Expand
Cation Chemistry in Titan’s Upper Atmosphere and its Influence on Tholin Formation
Titan is Saturn’s largest satellite. This object is unique in the solar system as it hosts a dense atmosphere mainly made of molecular nitrogen N and methane CH4, with a surface pressure of 1.5 bar.Expand
Photochemistry of HCN Ice on Tholins Simulated in Titan’s Lower Atmosphere Conditions
Titan’s organic atmospheric chemistry is unique in the Solar System. Revealed by the Voyager and ongoing Cassini Missions, a variety of latitudinal and altitudinal-changing trace species broken downExpand
Composition and chemistry of Titan's thermosphere and ionosphere
  • V. Vuitton, R. Yelle, P. Lavvas
  • Chemistry, Medicine
  • Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences
  • 2008
Observations of Titan's ionospheric chemistry indicate that molecular growth starts in the upper atmosphere rather than at lower altitude, and that Benzene (C6H6) is created by ion chemistry at high altitudes and its main photolysis product, the phenyl radical, is at the origin of the formation of aromatic species at higher altitude. Expand
The photochemical products of benzene in Titan’s upper atmosphere
Abstract The Cassini spacecraft detected benzene high in Titan’s atmosphere as well as the presence of large mass positive and negative ions. Previous work has suggested that these large mass ionsExpand
Volatile products controlling Titan's tholins production
A quantitative agreement between nitrile relative abundances and Titan’s atmospheric composition was recently shown with a reactor simulating the global chemistry occurring in Titan’s atmosphereExpand
Low-Temperature Alkaline pH Hydrolysis of Oxygen-Free Titan Tholins: Carbonates' Impact.
To produce reliable laboratory analogues of organic aerosols produced in Titan's atmosphere that play an important role in atmospheric and surface processes and in organic chemistry as it applies to exobiological interests, a device for the synthesis of clean tholins was developed and tested, and a list of potential precursors of these compounds was established. Expand
Nitrogen incorporation in Titan's tholins inferred by high resolution orbitrap mass spectrometry and gas chromatography–mass spectrometry
Abstract Influx of solar photons and heavy charged particles from Saturn's magnetosphere on Titan's atmosphere – mainly comprised of methane and nitrogen – induce an intense organic photochemistryExpand
Tholin Aggregation in Titan's Atmosphere: Developing a Probabalistic Model
Titan’s climate is dominated by a reddish haze in its atmosphere made of the organic aerosol tholin. This haze is known to influence the climate through temperature control, hydrocarbon productionExpand
Elusive anion growth in Titan’s atmosphere: Low temperature kinetics of the C3N− + HC3N reaction
Ion chemistry appears to be deeply involved in the formation of heavy molecules in the upper atmosphere of Titan. These large species form the seeds of the organic aerosols responsible for the opaqueExpand
A Study of Chemical Modeling for Several Precursors of Tholins in Titan's Atmosphere
Titan, one of the moons of Saturn, has an atmosphere rich in organic molecules. It is similar to the atmosphere of Primordial Earth. In Titan’s atmosphere, there are highly abundant conjugatedExpand


Titan's atmosphere is unique because dissociation of N2 and CH4, the primary atmospheric constituents, provides the H, C, and N atoms necessary for the synthesis of complex organic molecules. TheExpand
Photochemistry of the atmosphere of Titan: comparison between model and observations.
The photochemistry of simple molecules containing carbon, hydrogen, nitrogen, and oxygen atoms in the atmosphere of Titan has been investigated using updated chemical schemes and the authors' own estimates of a number of key rate coefficients, which satisfactorily accounts for the concentrations of minor species observed by the Voyager IRIS and UVS instruments. Expand
The abundances of constituents of Titan's atmosphere from the GCMS instrument on the Huygens probe
Direct atmospheric measurements from the Gas Chromatograph Mass Spectrometer (GCMS), including altitude profiles of the constituents, isotopic ratios and trace species (including organic compounds), were reported, confirming the primary constituents were confirmed to be nitrogen and methane. Expand
Mechanisms for the formation of benzene in the atmosphere of Titan
[1] Polycyclic aromatic hydrocarbons (PAHs) are important interstellar species, and their precursor benzene (C6H6) has been detected in our solar system. In this study the possibility of benzeneExpand
Models for Polar Haze Formation in Jupiter's Stratosphere
We present coupled chemical–microphysical models for the formation, growth, and physical properties of the jovian polar haze based on a gas-phase photochemical model for the auroral regions developedExpand
Ion Neutral Mass Spectrometer Results from the First Flyby of Titan
The Cassini Ion Neutral Mass Spectrometer (INMS) has obtained the first in situ composition measurements of the neutral densities of molecular nitrogen, methane, molecular hydrogen, argon, and a hostExpand
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- The ionic mechanism of soot formation assumes rapid growth of ions from the chemiion C3H3+ to form increasingly larger ions which either become incipient charged soot particles or combine withExpand
Ion-molecule chemistry in Titan's ionosphere
Abstract A summary is presented of the information available from laboratory studies of ion-molecule reactions that is relevant to the chemistry occurring in Titan's ionosphere. Reaction informationExpand
Physical properties of the organic aerosols and clouds on Titan
Abstract Titan's haze is optically thick in the visible, with an optical depth at 0.5 μm of about three. The haze varies with latitude in a seasonal cycle and has a detached upper layer.Expand
Laser flash photolysis of benzene. VIII. Formation of hot benzene from the S2 state and its collisional deactivation
Time‐resolved absorption spectra of gaseous benzene have been observed in the time range from 0 to 4 μs with an ArF laser (193 nm) as an excitation source, which pumps the S2 state. The absorptionExpand