What's going on with comet Wirtanen?

1 Jun 2018

Comet Wirtanen has been recovered!

46P/Wirtanen was recovered on May 8, 2018 in images obtained by Nick Moskovitz (Lowell Observatory), in collaboration with Tony Farnham and Matthew Knight (University of Maryland). Six images of the comet were obtained at the Discovery Channel Telescope operated by Lowell Observatory. They were acquired during astronomical twilight at 4.5-5.1 airmass. A coadded version of the images is shown below.

At the time of the recovery, Wirtanen was at a heliocentric distance of 2.61 AU, geocentric distance of 2.80 AU, and had an r' magnitude of 20.3. There is no obvious coma visible in the images, but the comet's brightness suggests that it is already exhibiting activity.

The updated orbit solution confirms that Wirtanen will make its close approach to the Earth at a distance of 0.078 AU on December 16, 2018, but with only limited 2018 observations, the exact time of close approach has an uncertainty of several hours. Additional astrometry is requested to refine the orbit and constrain the effects of non-gravitational forces.

Recovery image
of comet 46P/Wirtanen