45P/Honda-Mrkos-Pajdusakova's background

Discovery and Subsequent Apparitions

H-M-P was first discovered on December 3, 1948 by Minuru Honda. It was independently discovered on December 6 by Ludmilla Pajdusakova and on December 7 by Antonin Mrkos. Since then, it has been observed on every apparition except for its 1959 and 1985 passages, when it was close to the Sun throughout those apparitions.

Encounters with Jupiter

At aphelion, H-M-P approaches Jupiter's orbit. Over the last few apparitions (and future ones), it has been close enough to Jupiter to experience a number of significant perturbations that have caused its orbit to evolve.

Date Distance from Jupiter Change in Perihelion Distance Change in Orbital Period
Aug 5, 1935 0.08 AU 0.64 →  0.58 AU 5.53 →  5.27 yr
Mar 26, 1983 0.11 AU 0.58 →  0.54 AU 5.28 →  5.30 yr
Aug 3, 2030 0.17 AU 0.56 →  0.63 AU 5.34 →  5.52 yr

Recent and Upcoming Apparitions

H-M-P's current orbit, with a 5.3 year period, is such that it cycles through three observational opportunities. One apparition will be poor, when the comet is on the far side of the Sun around the time of perihelion (e.g., 2006), followed by an appartion where it is positioned well for pre-perihelion observations (2011), and then one that is positioned for post-perihelion observations (2016/2017).

H-M-P has made several recent close approaches to the Earth, including one in 1996 at a distance of 0.1702 AU, another in 2011 at 0.089 AU, and most recently on Feb 11, 2017 at distance of 0.083 AU.

Many thanks to Gary Kronk and his Cometography books for contributions to this history.