TITAN A MOON WITH AN ATMOSPHERE
Ashley Gilliam Earth 450 – Satellites of Jupiter and Saturn 4/29/13 SATURN HAS > 60 SATELLITES, WHY TITAN?
Is the only satellite with a dense atmosphere
Has a nitrogen-rich atmosphere resembles Earth’s
Is the only world besides Earth with a liquid on its surface • Possible habitable world
Based on its size… Titan a planet in its o ght!
R = 6371 km R = 2576 km R = 1737 km Ch iaan Huy ns (1629-1695) DISCOVERY OF TITAN
Around 1650, Huygens began building telescopes with his brother Constantijn
On March 25, 1655 Huygens discovered Titan in an attempt to study Saturn’s rings
Named the moon Saturni Luna (“Saturns Moon”)
Not properly named until the mid-1800’s THE DISCOVERY OF TITAN’S ATMOSPHERE
Not much more was learned about Titan until the early 20th century
In 1903, Catalan astronomer José Comas Solà claimed to have observed limb darkening on Titan, which requires the presence of an atmosphere
Gerard P. Kuiper (1905-1973) José Comas Solà (1868-1937) This was confirmed by Gerard Kuiper in 1944
Image Credit: Ralph Lorenz Voyager 1 Launched September 5, 1977 M sions to Titan
Pioneer 11 Launched April 6, 1973
Cassini-Huygens Images: NASA Launched October 15, 1997 Pioneer 11
Could not penetrate Titan’s Atmosphere!
Image Credit: NASA
Vo y a r 1
Image Credit: NASA
Vo y a r 1
What did we learn about the Atmosphere?
• Composition (N2, CH4, & H2) • Variation with latitude (homogeneously mixed) • Temperature profile Mesosphere • Pressure profile
Stratosphere
Troposphere
Image Credit: Fulchignoni, et al., 2005
Image Credit: Conway et al. 2003 What is the main similarity between Earth’s atmosphere and Titan’s?
From Conway et al. 2003 Credit: C. P. McKay M = P P = atmospheric pressure g g = gravita onal accelera on
Titan: N kg 1 Pa = 1 = 1 m2 m s2 P = 1.5 bar = 1.5×105 Pa ! g = 1.35 m s-2
M = 1.1 × 105 kg m-2 The column mass is greater on Titan. More substan al atmosphere. Earth:
P = 1 bar = 1×105 Pa g = 9.78 m s-2
M = 1.0 × 104 kg m-2 Casini-Huy ns RADAR-SAR instrument was able to penetrate Titan’s thick veil of haze
Pre-Cassini Cassini
Image Credit: NASA Image Credit: NASA
e Huy ns Probe • Goals of the mission: • Collect aerosols for chemical analysis • Make spectral measurements and take pictures of Titan’s surface and atmosphere • Measure wind speeds • Identify composition of the atmosphere • Measure the physical properties of the atmosphere • Determine the physical state, topography, and composition of the surface The Huygens probe separated from thee Cassini Huy orbiter on Decemberns Probe 25, 2004
Took 148 minutes to descend through the atmosphere
Was prepared to touch down on land or liquid
Based on the pictures taken by Cassini 1,200 km away, the landing site appeared to resemble a shoreline HUYGENS LANDING SITE
Landed January 14, 2005 at 10.2°S, 192.4°W
Discovered small “rocks”, possibly made of water ice, at the landing site.
Fluvial activity (methane?)
Images taken during descent showed no open areas of liquid, but indicated liquid had once flowed
Titan Earth
Image Credit: NASA POSSIBLE SHORELINE
100 km LAKES ON TITAN
Image Credit: NASA Titan: Ligeia Mare Earth: Lake Superior Image Credit: William Hubbard, UA LPL AN ALIEN ENVIRONMENT
TITAN EARTH
Surface Liquid: Liquid methane & ethane Water
Surface: Ice Rock
Surface Composition: Hydrocarbons Dirt
Titan’s South Pole Clouds over a five hour period
Credit: C. P. McKay Credit: C. P. McKay COMPARING TITAN AND EARTH
Property Titan Earth
Gravity 1/7 1
Pressure 1.5 atm 1 atm
Atmosphere N2, CH4 N2, O2 ,CO2
Clouds & Rain CH4, C2H6 H2O
Greenhouse N2, CH4, H2 CO2, H2O
Temperature -180oC +15oC
Rotation 16 days 1 day
Solar Orbit 30 years 1 year Habitability of Titan
Titan = 0.64
Mars = 0.59
Gliese 581d = 0.43
Credit: Popular Science Future M sions
Aerial Vehicle for In-Situ and Airborne Titan Reconnaissance (AVIATR)
Titan Saturn System Mission (TSSM)
Titan Mare Explorer (TiME)