Some technical data on Titan I composed

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thalion

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I've had a little trouble finding more technical information on Titan online, so I decided to do a little research and post what I've found. Hopefully this will be useful for someone.<br /><br />Titan Facts<br /><br />Mass: 1.347x10^23 kg<br />Radius: 2575 km (solid body), 2775 km (inc. atmosphere)<br />Density: 1.88 x 10^3 kg/m^3<br />Hill Radius / <br />Tidal Radius: 5.2432 x 10^4 km*<br />Escape velocity<br />at surface: 2.640 km/s<br />Gravity at surface: 1.354 m/s^2 (Earth, 9.78 m/s^2)<br /><br />Semimajor axis: 1.2218 x 10^6 km<br />Eccentricity: 0.02919<br />Inclination: 0.33 deg<br />Increase of line<br />of apsides: 0.5213 deg / yr<br />Tropical period: 15.945421 d (22.577014 deg / d*)<br />Mean orbital velocity: 5.5721 km/sec*<br /><br />Geometric albedo: 0.22<br />Avg. mag. at opp.: 8.28<br />Abs. mag V (1,0): -1.28<br />B-V mag: 1.28<br />Max. elong. at mean opp.: 3' 17" (197"*) <br /><br />Atmospheric pressure at surface: 1.4953 bar<br />Atmospheric density at surface: 5.55 km/m^3 (Earth, 1.23 kg / m^3)<br />Scale height: ~20.2 km<br />Blackbody Temp.: 90 K<br />Surface Temp.: 94 K<br />Major Components: N2, Ar, CH4<br />Mean mol. weight: ~28.6 g/mol<br /><br />*Figures with asterisks were calculated. The formula for calculating the Hill Radius (or Hill Sphere) is familiar, and available from many online sites. I used<br />the following example:<br /><br />Hr = a * (m / 3(M+m)^.3333<br /><br />M = mass of larger body<br />m = mass of smaller body<br />a = semimajor axis<br /><br />More often than not, m is omitted, but it can be included if the objects are similar<br />in mass.<br /><br />References:<br /><br />Hartmann, William K. <i>Moons & Planets.</i> Fourth edition. Belmont: Wadsworth Publishing Co., 1999.<br /><br />Lodders, Katharina, and Bruce Fegley, Jr. <i>The Planetary Scientist's</i>
 
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bobvanx

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Wow, cool beans! Thanks, Thalion!<br /><br />I saw that the surface gravity calculates out to be about .14 that of Earth. I'd weigh there, about as much as 3 gallons of water does here. Wow, I could throw me over a house!!!<br /><br />I love thinking about such a low escape velocity with such a big atmosphere. This is, roughly 1/4 that of Earth? Ours is about 11km/sec. Lets see, that means that a ram-jet engine (Mach 5-ish) has the speed you need to get into orbit around Titan.
 
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thalion

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Thanks much. <img src="/images/icons/smile.gif" /><br /><br />Actually, when considering the escape velocity we definitely need to factor in the substantial air resistance we'd encounter, and the fact that that drag would be operating over a greater distance than on Earth (due to the deeper atmosphere). Also, the escape velocity from Saturn at Titan's distance is roughly the square root of 2 times the orbital velocity, which would be about 7.9 km/s. Added to Titan's escape velocity, the total delta V needed would be about 10.5 km/s, only slightly less than Earth's escape velocity. This isn't counting the extra energy needed to stray far from Saturn's orbit. A Titan surface return would be quite difficult.
 
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vogon13

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What about GNP? Population? Chief exports? NFL teams?<br /><br />Seriously, you have provided a very handy (and timely) reference. Thanx! <div class="Discussion_UserSignature"> <p><font color="#ff0000"><strong>TPTB went to Dallas and all I got was Plucked !!</strong></font></p><p><font color="#339966"><strong>So many people, so few recipes !!</strong></font></p><p><font color="#0000ff"><strong>Let's clean up this stinkhole !!</strong></font> </p> </div>
 
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newtonian

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Thalion - Thank you.<br /><br />On atmospheric content:<br /><br />I understand Nitrogen predominates, but at what percentage? Ditto other components?<br /><br />I note you mention methane (=CH4). Recent broadcasts on TV [this is space week on the Science channel] mentioned ethane was also found.<br /><br />Is this confirmed?
 
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thalion

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The data I was using was was presumably from the Voyager flyby, but it was not precise on the atmospheric content--the percentages for N2 alone in the <i>Planetary Scientist's Companion</i> ranged from 65% to over 90%. One of my books gives figures of ~90%, 10%, and a "few percent" of N2, Ar, and CH4 respectively, but those all ballpark figures. Huygens and Cassini will hopefully render such rough data obsolete. By the way, the source for that info is Chaisson and McMillan's <i>Astronomy Today</i>, (Englewood Cliffs: Prentice-Hall, Inc., 1993). By the way, if you can find a newer edition of this text, it's a great book--perhaps my most informative astronomy text, even for its age.<br /><br />I've since edited the first post to include Titan's B-V magnitude, which indicates that it is (as we all knew) quite red.<br /><br />And, thank you all for your compliments. <img src="/images/icons/smile.gif" /><br />
 
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newtonian

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Thallion- right now airing on the Science channel is a special on the Huygens probe on Titan. I am taping it and hope to get more info.<br /><br />It will be repeated tonight and tomorrow, along with programs on Mars and Jupiter. All 3 are one hour specials. <br /><br />I will start a thread on that.
 
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