The Asteroid/Comet Connection's
daily news journal about
asteroids, comets, and meteors

Today's issue status: done

• News briefs – one-way traffic + bits & pieces
• Risk monitoring

Cover: This animation by Pasquale Tricarico was created with his ORSA software to demonstrate the retrograde hyperpolic path of comet C/2003 K4 (LINEAR) through the inner Solar System. One set of frames shows how the path crosses through the ecliptic near Earth's orbit this coming September 30th while the Earth is elsewhere, and another set follows the comet (at 0.0131 Earth radius) on its path while keeping the view centered on the Sun. (Hit [Esc] to stop, and use refresh to restart.) See below for more about this comet's near-Earth experience, and see C/2003 K4 images by Pepe Manteca on Saturday's "cover."

One-way traffic:  Comet C/2003 K4 (LINEAR) was discovered on the 28th of this month one year ago, 491 days before it will come to about 20 lunar distances from Earth's orbit, at the 0.05 AU limit that defines objects as "potentially hazardous" if they are on closed orbits (eccentricity e<1.0). C/2003 K4, however, has fallen in from the Oort Cloud on a hyperbolic (e=1.000326) retrograde (i=134.3°) path that comes closest to the Sun at 1.024 AU this October 13th and then heads out forever into interstellar space.

After Pepe Manteca's Saturday "cover" with pictures of C/2003 K4, A/CC asked Pasquale Tricarico for information about how close this object will, and could have, come to Earth. He used his Orbit Reconstruction, Simulation, and Analysis (ORSA) software to report that it comes closest to Earth's orbit this coming September 30th, two weeks before perihelion. C/2003 K4 won't come nearly so close to Earth itself, but gets closest twice due to how it is rounding the Sun in reverse direction at a steep

angle to Earth's orbit. It will be at 1.42 AU on July 7th, and at 1.15 AU on December 24th. Between those two dates, C/2003 K4 will be as far away from Earth as 2.04 AU. This occurs on September 28th, just two day's before its closest approach to Earth's orbit. And that closest point is where Earth is on its orbit every April 9th. So we are all missing what could have been a spectacular comet show (and very public comet hazard wakeup call) by about half a year. See the cover above for animated orbit illustrations from ORSA.

Bits & pieces:  Cometography has a nice collection of C/2004 F4 (Bradfield) images, and BBC profiled discoverer William Bradfield today. And the Christian Science Monitor has a report about other current comet news today, "The comets are coming!"

Space.com has an article today, "Details Emerge in Robotic Plan to Service Hubble." And SpaceRef.com yesterday posted a new NASA presolicitation notice, "Hubble Space Telescope (HST) Robotic Servicing/Deorbit Module." It replaces Friday's notice, which lacked the "Robotic Servicing" part.

Risk monitoring 4 May

Of five objects currently listed with impact solutions and recently in view, none are reported in the Tuesday Daily Orbit Update MPEC. (This is not unusual during the time of the full Moon.)