I’m still playing catch-up, and I appreciate everybody’s patience.  Today I’m writing about Comet Elenin, which is Jerry’s post.

This is from the JPL small-body database

Comet Elenin (C/2010 X1) is a fascinating little critter discovered December 10th, 2010, by Russian astronomer Leonid Elenin.  Mr. Elenin was using the International Scientific Optical Network’s robotic observatory in New Mexico when he made his discovery.  Back in December, when the tiny comet was first seen, it had an apparent magnitude of 19.5.  Remember, in order to be visible to the unaided eye, an object must have an apparent magnitude of about 6.5.  An object becomes more visible the smaller the number.  The Sun has an apparent magnitude of negative 26.74, which is so visible you risk injury to your eyes trying to catch a glimpse of it.

Image taken 030411 by Jean-Francois Soulier, all rights reserved

Since little Elenin was just discovered like 20 minutes ago, not much is known about it yet.  It’s believed to be about 3-4 kilometers in diameter, traveling at about 86,000 km/hr.  Elenin will come to perihelion on about September 10th, 2011, and will come closest to the Earth on about October 16th, 2011.  It will pass within about 34,000,000 km (about 21,000,000 miles) of the Earth.  It’s not known how visible little Elenin will be at that time, but if you train your telescopes on Mars around October 15th, you should be able to see it approach and pass in front of the planet as it heads out away from the Sun.

Image by Bernhard Hausler, 030611, all rights reserved

As I said before, not much is known about Comet Elenin, so most information is speculative.  Right now, many astronomers believe Elenin’s previous orbital period of about 4.1 million years (with aphelion at about 0.82 ly, or 51,800 AU) was only recently disrupted, shooting it out of the Oort Cloud into the inner solar system, and giving it aphelion at about 1033 AU.  Now, you realize that when I say “recently”, I mean within the last couple of million years.  Elenin’s current orbital period is believed to be about 11,750 years.

However speculative the information on Elenin’s current orbit, this little comet will most assuredly not pass this way again in your lifetime.  Be sure to mark your calendars for October 15th, grab your telescope, and watch this tiny speed-freak buzz Mars.