Worldwide pro-am help sought for comet trio study

Planetary Science Institute

Comet 45P/Honda-Mrkos-Pajdušáková is one of three comets that organisers of the 4*P Coma Morphology Campaign would like amateur and professional astronomers to observe in their close approaches to Earth over the next two years. Comet 45P passes just 0.083 astronomical units (7.73 million miles, or 32 lunar distances) from Earth on the morning of 11 February 2017. Image credit: NASA JPL Small-Body Database Browser/Osamu Ajiki/Ron Baalke/Ade Ashford.
Comet 45P/Honda-Mrkos-Pajdušáková is one of three comets that organisers of the 4*P Coma Morphology Campaign would like amateur and professional astronomers to observe in their close approaches to Earth over the next two years. Comet 45P passes just 0.083 astronomical units (7.73 million miles, or 32 lunar distances) from Earth on the morning of 11 February 2017. Image credit: NASA JPL Small-Body Database Browser/Osamu Ajiki/Ron Baalke/Ade Ashford.
Amateur and professional astronomers are invited to provide observations of three comets that will make close approaches to Earth over the next two years.

“We are organising a worldwide coma morphology campaign for three comets,” said Nalin Samarasinha, Senior Scientist at the Planetary Science Institute, who is leading the project. “Two of these comets will have close approaches to Earth in early 2017 while the third one will come close in late 2018. We want to get both professional and amateur astronomers involved in the campaign.”

The three comets are 41P/Tuttle-Giacobini-Kresák, 45P/Honda-Mrkos-Pajdušáková, and 46P/Wirtanen. The comets will pass by Earth at distances ranging from 0.08 AU to 0.15 AU. (AU, or Astronomical Unit, is the mean distance from the Sun to Earth: 149,597,870.7 kilometres.) Such close approaches of three comets within two years are rare and typically occur only once every few decades.

The other organisers of the 4*P Coma Morphology Campaign are PSI Senior Scientist Beatrice Mueller, University of Maryland scientists Matthew Knight and Tony Farnham, and Walt Harris, a scientist from the University of Arizona.

“For most of the time when an active comet is close to the Earth and easily studied, we expect the comet to have a coma with embedded structures. However, it cannot be continuously monitored from a given location thus we would miss crucial time-dependent phenomena,” Samarasinha said. “An international campaign observing the comet from around the globe would allow better temporal coverage, allowing 24/7 observations of the comet across all longitudes.”

The team is seeking continuum (dust) images as well as gas images with good signal-to-noise.

Visit the Planetary Science Institute website for more information on participating in the project.