* Astronomy

Members Login
Post Info
TOPIC: Titan


L

Posts: 128137
Date:
RE: Titan
Permalink  
 


The Cassini probe has detected propene, or propylene, on Saturn's moon Titan.
On Earth, this molecule, which comprises three carbon atoms and six hydrogen atoms, is a constituent of many plastics.

Read more



__________________


L

Posts: 128137
Date:
Titan ice shell
Permalink  
 


New Cassini data from Titan indicate a rigid, weathered ice shell

An analysis of gravity and topography data from Saturn's largest moon, Titan, has revealed unexpected features of the moon's outer ice shell. The best explanation for the findings, the authors said, is that Titan's ice shell is rigid and that relatively small topographic features on the surface are associated with large roots extending into the underlying ocean. The study is published in the August 29 issue of the journal Nature.
Read more



__________________


L

Posts: 128137
Date:
RE: Titan
Permalink  
 


Cassini Sees Precursors to Aerosol Haze on Titan

Scientists working with data from NASA's Cassini mission have confirmed the presence of a population of complex hydrocarbons in the upper atmosphere of Saturn's largest moon, Titan, that later evolve into the components that give the moon a distinctive orange-brown haze. The presence of these complex, ringed hydrocarbons, known as polycyclic aromatic hydrocarbons (PAHs), explains the origin of the aerosol particles found in the lowest haze layer that blankets Titan's surface. Scientists think these PAH compounds aggregate into larger particles as they drift downward.
Read more



__________________


L

Posts: 128137
Date:
Permalink  
 

Saturn's moon Titan might be in for some wild weather as it heads into its spring and summer, if two new models are correct. Scientists think that as the seasons change in Titan's northern hemisphere, waves could ripple across the moon's hydrocarbon seas, and hurricanes could begin to swirl over these areas, too. The model predicting waves tries to explain data from the moon obtained so far by NASA's Cassini spacecraft. Both models help mission team members plan when and where to look for unusual atmospheric disturbances as Titan summer approaches.
Read more



__________________


L

Posts: 128137
Date:
Permalink  
 

Cassini Shapes First Global Topographic Map of Titan

pia17030-640.jpg

Scientists have created the first global topographic map of Saturn's moon Titan, giving researchers a valuable tool for learning more about one of the most Earth-like and interesting worlds in the solar system. The map was just published as part of a paper in the journal Icarus.
Read more



__________________


L

Posts: 128137
Date:
Permalink  
 

Title: In Situ Measurements of the Size and Density of Titan Aerosol Analogues
Authors: Sarah M. Horst, Margaret A. Tolbert

The organic haze produced from complex CH4/N2 chemistry in the atmosphere of Titan plays an important role in processes that occur in the atmosphere and on its surface. The haze particles act as condensation nuclei and are therefore involved in Titan's methane hydrological cycle. They also may behave like sediment on Titan's surface and participate in both fluvial and aeolian processes. Models that seek to understand these processes require information about the physical properties of the particles including their size and density. Although measurements obtained by Cassini-Huygens have placed constraints on the size of the haze particles, their densities remain unknown. We have conducted a series of Titan atmosphere simulation experiments and measured the size, number density, and particle density of Titan aerosol analogues, or tholins, for CH4 concentrations from 0.01% to 10% using two different energy sources, spark discharge and UV. We find that the densities currently in use by many Titan models are higher than the measured densities of our tholins.

Read more (1177kb, PDF)



__________________


L

Posts: 128137
Date:
Permalink  
 

Titan's Methane: Going, Going, Soon to Be Gone?

PIA16844.jpg

By tracking a part of the surface of Saturn's moon Titan over several years, NASA's Cassini mission has found a remarkable longevity to the hydrocarbon lakes on the moon's surface.
A team led by Christophe Sotin of NASA's Jet Propulsion Laboratory in Pasadena, Calif., fed these results into a model that suggests the supply of the hydrocarbon methane at Titan could be coming to an end soon (on geological timescales). The study of the lakes also led scientists to spot a few new ones in images from Cassini's visual and infrared mapping spectrometer data in June 2010.

Read more



__________________


L

Posts: 128137
Date:
Permalink  
 

Ice Cloud Heralds Autumn at Titan's South Pole

An ice cloud taking shape over Titan's south pole is the latest sign that the change of seasons is setting off a cascade of radical changes in the atmosphere of Saturn's largest moon. Made from an unknown ice, this type of cloud has long hung over Titan's north pole, where it is now fading, according to observations made by the composite infrared spectrometer (CIRS) on NASA's Cassini spacecraft.
Read more



__________________


L

Posts: 128137
Date:
Permalink  
 

NASA Team Investigates Complex Chemistry at Titan

A laboratory experiment at NASA's Jet Propulsion Laboratory, Pasadena, Calif., simulating the atmosphere of Saturn's moon Titan suggests complex organic chemistry that could eventually lead to the building blocks of life extends lower in the atmosphere than previously thought. The results now point out another region on the moon that could brew up prebiotic materials. The paper was published in Nature Communications this week.
Read more



__________________


L

Posts: 128137
Date:
Permalink  
 

Title: Nitrogen in the stratosphere of Titan from Cassini CIRS infrared spectroscopy
Authors: Conor A. Nixon, Nicholas A. Teanby, Carrie M. Anderson, Sandrine Vinatier

In this chapter we describe the remote sensing measurement of nitrogen-bearing species in Titan's atmosphere by the Composite Infrared Spectrometer (CIRS) on the Cassini spacecraft. This instrument, which detects the thermal infrared spectrum from 10-1500 cm-1 (1000-7 microns) is sensitive to vibrational emissions of gases and condensates in Titan's stratosphere and lower mesosphere, permitting the measurement of ambient temperature and the abundances of gases and particulates. Three N-bearing species are firmly detected: HCN, HC3N and C2N2, and their vertical and latitudinal distributions have been mapped. In addition, ices of HC3N and possibly C4N2 are also seen in the far-infrared spectrum at high latitudes during the northern winter. The HC(15)N isotopologue has been measured, permitting the inference of the 14N/15N ratio in this species, which differs markedly (lower) than in the bulk nitrogen reservoir (N2). We also describe the search in the CIRS spectrum, and inferred upper limits, for NH3 and CH3CN. CIRS is now observing seasonal transition on Titan and the gas abundance distributions are changing accordingly, acting as tracers of the changing atmospheric circulation. The prospects for further CIRS science in the remaining five years of the Cassini mission are discussed.

Read more (978kb, PDF)



__________________
«First  <  1 2 3 4 548  >  Last»  | Page of 48  sorted by
Quick Reply

Please log in to post quick replies.



Create your own FREE Forum
Report Abuse
Powered by ActiveBoard