MercuryMars

Earth

• First passage of comet through inner solar system since formation and ejection- Likely contains some of the most pristine material left in the solar system- Detailed orbital knowledge for an Oort comet perturbed many Mya to into inner system

• On a Sungrazing Orbit, with > 1 yr lead time since discovery- Perihelion on Nov 28, 2013 at rh = 2.7 RSun, so close all dust & gas will atomize

• ISON will have close encounters with Mars (C.A. = 0.07 AU), Mercury (C.A. = 0.24 AU), Sol, Earth(?) (C.A. = 0.44AU), & Venus (C.A.=0.42 AU) in 2013.

• The last time(s) this happened, in 1965 with Comet Ikeya-Seki, we observed one of the 10 brightest comets ever as it disintegrated at the Sun; and in 1973, when Comet Kohoutek mysteriously bloomed in the outer S.S. then faded away. But now we have > 18 s/c at Mars, Venus, Mercury, Earth, and others watching the Sun 24/7, that can study ISON.

The Scientific Importance of Comet C/2012 S1 (ISON)

Earth

Sol

Spitzer 6/13/13

Dust Gas

HST 4/10/13

Dust

Ice Jet?