Long awaited, Comet PanSTARRS is on track to peak at only magnitude +2 or +3 in the March evening twilight for Northern Hemisphere skywatchers, not –1 as originally predicted.As we report in the print edition of S&T, Comet PanSTARRS (C/2011 L4) will emerge from the Sun's glare low in the western twilight in early and mid-March of 2013. But how bright will it be?
Fainter than we originally predicted.
More than a month ago, using brightness measurements coming from Southern Hemisphere observers, Seiichi Yoshida, editor of Weekly Information about Bright Comets, changed his magnitude formula for Comet PanSTARRS. His new predicted light curve (scroll down there) had the comet peaking at only magnitude +3 in early March.
In the month since then, with many more brightness estimates coming in from Southern Hemisphere observers, there has been little or no change in that new prediction.
As we warned in print, the slightly hyperbolic orbit of PanSTARRS indicates that it's a fresh comet from the outer Oort Cloud being warmed by the Sun for the first time. Such comets have quite a history of brightening early with the promise of great things to come, and then weakening after a thin, virgin coating of volatiles on the nucleus evaporates off.
For further news as it develops, and recent images, bookmark our Updates on Comet PanSTARRS.