New Magnitude Prediction for Comet Hyakutake

New Magnitude Prediction for C/1996 B2 (Hyakutake)

Unfortunately, this comet is not living up to its advanced billing as it approaches perihelion. The power-law exponent, which represents the rate of brightening, is decreasing as the comet approaches perihelion (May 1). The following predictions are based on 11 estimates made by C. S. Morris from 1996 April 5-19 UT which give the following formula: m1 = 4.90 + 5 log (delta) + 7.65 log r.

 
   UT Date      
  (0 hours)      m1
 1996  4 20     1.8
 1996  4 21     1.7
 1996  4 22     1.6
 1996  4 23     1.5
 1996  4 24     1.3
 1996  4 25     1.2
 1996  4 26     1.0
 1996  4 27      .8
 1996  4 28      .7
 1996  4 29      .5
 1996  4 30      .4
 1996  5  1      .4
 1996  5  5      .9
 1996  5 10     2.1
 1996  5 15     3.0
 1996  5 20     3.7
 1996  5 25     4.2
 1996  5 30     4.7

Because the comet will be close to the horizon in a dark sky or only visible in twilight (or in daytime around perihelion), the comet will look less impressive than these magnitudes suggest. As always, comet brightness can change unexpectedly.

You can find additional information, images (hundreds), up-to-date observations, light curves, etc. for Hyakutake and other comets at the Comet Observation Home Page (http://encke.jpl.nasa.gov).

 
Charles S. Morris
Jet Propulsion Laboratory
csm@encke.jpl.nasa.gov

Comet 1996 B2 Hyakutake Home Page