Comet Tuttle-Giacobini-Kresak's 2017 Apparition

T-G-K made its closest approach to the Earth since its discovery

  • Occurred Apr 1, 2017
    • Just 11 days before perihelion
    • The comet is near its brightest
  • Geocentric Distance
    • 0.142 AU
    • 56 Lunar distances
    • 21.2 million km
    • 13.2 million miles

T-G-K is fairly bright and can exhibit outburst activity

  • In its quiescent state, T-G-K is bright enough to see with binoculars or a small telescope.
  • If it experiences outbursts around perihelion, it is likely to reach naked eye brightness, and if the outburst is large enough, it could put on a nice show.

Observing conditions are excellent

  • Conditions are better than originally thought
    • Approaching its 2017 apparition, 41P/T-G-K was recovered Nov 10, 2016. Orbit solutions that used the newest positions showed that the comet would reach perihelion on Apr 12, 2017, almost a day earlier than predicted from the previous solution. This change in its orbit shifted the date of perigee by almost 4 days, moving it to April Fools Day, and reduced the closest approach to Earth to 0.142 AU (previously 0.148 AU).
  • Solar elongation is large for most of 2017
    • In the northern hemisphere, it is visible for most of the night around close approach
    • Visible for many hours for months before and after close approach (both Northern and Southern hemispheres)

Great apparition for studying the comet

  • Small geocentric distance offers close-up views
    • High spatial resolution (1 arcsec spans 103 km at close approach)
    • Unique opportunity to image and measure the inner coma
    • Use radar characterize the nucleus itself
  • Brightness allows many techniques to be used
    • High spectral resolution spectroscopy
    • Detailed composition measurements
  • Observability allows extensive temporal studies
    • Long-term secular behavior
    • Rotational variability
    • Outburst monitoring
    • Solar phase dependencies