On February 12/13, 2019 comet Iwamoto makes a rare visit to our corner of the universe. Discovered in 2018 by amateur Japanese astronomer Massayuki Iwamoto, his namesake passes harmlessly at a distance of 45 million km. with astronomical magnitude of +6.5 – too faint for the human eye, easily observed by backyard telescopes. With a wonky elliptical orbit of 1,371 years, comet Iwamoto hasn’t said hello since 648 AD and won’t be back until the year 3390. Point your telescope toward constellation Leo around midnight on the 12th to catch a glimpse of Iwamoto.
Comet Iwamoto (C/2018 Y1) hails from beyond the Kuiper Belt. Officially this Extreme Trans-Neptunian Object (ETNOs) comes from a distance 5 times greater than that of Pluto to the Sun. Regarded as a “dirty snowball” –
“The most popular theory about the nature of comets was put forward by American astronomer Fred Whipple, often known as the “grandfather” of modern cometary science. Whipple believed they were like dirty snowballs – large chunks of water ice and dust mixed with ammonia, methane and carbon dioxide. As the snowball approached the Sun, its outer ices began to vapourise, releasing large amounts of dust and gas which formed the characteristic tails.
Today, largely thanks to data from Giotto and the Russian Vega spacecraft, we now know that Whipple’s model was fairly accurate. A comet nucleus resembles a fluffy snowball (usually only a few kilometres across) coated with a crust of black material and spouting jets of vaporised ice.”
Only a handful of keeners will witness Iwamoto’s passing. Seeing it matters less than knowing it’s out there and tipping your hat to cosmic wonder.