M
MeteorWayne
Guest
<p>Currently it's the highest risk object on the JPL Sentry Risk page among recently observed objects (Torino Scale -2.59 on Feb 21,2010).</p><p>It's a large asteroid, (~ 900 meters diameter) and if the best fit orbit is correct can never actually hit earth since it's aphelion (furthest distance from the sun) is inside of earth's perihelion (closest to the sun).</p><p>However, the node (where it crosses the plane of the earth's orbit, i.e. the only time an impact can occur) is close to earth. It's in a highly inclined (42 degree) orbit, close to circular, and basically orbiting between Venus and the Earth's orbital distances.</p><p>The uncertainties are quite large since the entire observational arc is less than a full day so far, on January 3rd.</p><p>Here's the 3D orbit page from JPL:</p><p>http://ssd.jpl.nasa.gov/sbdb.cgi?sstr=2009+AV;orb=1 </p><p>You can use the handle at the very bottom to zoom in, and the handle on the right to change the view from overhead in the solar sytem (which shows the orbit is inside that of the earth) to along the plane of the solar system (which shows it's large inclination).</p><p>As you can see if you run the animation, the best fit orbit places in nearly a quarter of an orbit past the earth on Feb 21, 2010. The reason the risk is so high is that with such a short period of observation (only 1 day) the uncertainties in it's orbital speed are so large it could actually wind up closer the earth.</p><p>It should be interesting to watch things change as new observations come in to constrain the uncertainties in the orbit.</p><p>If you've got a REALLY big scope it is visible at ~ Magnitude +20 between Virgo and Libra in the early morning sky.</p><p>Wayne</p> <div class="Discussion_UserSignature"> <p><font color="#000080"><em><font color="#000000">But the Krell forgot one thing John. Monsters. Monsters from the Id.</font></em> </font></p><p><font color="#000080">I really, really, really, really miss the "first unread post" function</font><font color="#000080"> </font></p> </div>