46P/Wirtanen Home Page
What is special about comet Wirtanen?
- Wirtanen is a "hyperactive" comet.
Hyperactive comets are a small family of comets whose activity levels are higher than expected. They seem to emit more water than they should for the size of their nucleus. (Comet 103P/Hartley 2, the target of the Deep Impact extended mission, is another hyperactive comet.)
- Wirtanen is a prime spacecraft target.
The comet has an orbit that makes it readily accessible for a spacecraft rendezvous. Wirtanen was the original target of the Rosetta spacecraft, which retargeted to 67P/Churyumov-Gerasimenko after their original launch was delayed. It was also the target of the Comet Hopper Discovery mission, which progressed through the Phase A proposal, but was not selected for flight. Given its accessibility, it is likely that Wirtanen will be the target of future missions as well, and so we are interested in learning as much about it as we can.
- Wirtanen can get very close to the Earth.
Wirtanen can approach the Earth at distances as small as 0.071 AU. Although this does not technically place it under the category of a "potentially hazardous object" (requires a distance <0.05 AU), it is possible that its non-gravitational forces and close approaches to Jupiter could someday nudge it into an orbit that could change its status. In the mean time, its 2018 apparation will bring it to within 0.077 AU of the Earth, providing an excellent opportunity to study it in detail.
For more information about the 2018 apparition, click on the menu item to the left.