Hale-Bopp: A Continuing Tail

Explanation: Where is Hale-Bopp now? The Great Comet of 1997 , one of the largest and most active comets ever, is outbound about 400 million miles from the sun. Too faint for viewing without telescopes or binoculars, Hale-Bopp is presently positioned in the very southerly constellation of Pictor . This “negative” image (black stars against white sky) of Hale-Bopp is the result of a 1 hour time exposure using the 1-metre European Southern Observatory Schmidt telescope on January 5. Clearly the comet still has a substantial tail , blown by the solar wind , that points generally away from the sunward direction. But look closely. A spiky “anti-tail” is also visible pointing toward the sun! It is likely that this anti-tail is composed of dust grains released from the comet nucleus which are too large to be easily pushed by the solar wind. As Hale-Bopp recedes from the sun its activity will subside but astronomers are still uncertain as to how long its tails will last. After a swing through the outer solar system and the Oort cloud , Hale-Bopp will pass through the inner solar system again ... around the year 5400.