Skywatchers using the online Slooh system for real-time broadcast of celestial images were among the first on February 12, 2017 to confirm that the nucleus of passing comet 73P/Schwassmann-Wachmann has split into at least two large pieces. Slooh members using the company’s telescopes in Chile were able to view the comet as it broke.
This seems to be the continuation of a process that was first witnessed in 1995, then again in 2006 …
Comets are fragile, icy bodies that do sometimes break up as they pass nearest the sun that binds them in orbit, and comet 73P will reach its perihelion – or closest approach to the sun – on March 16, 2017.
In 2025, comet 73P will come within 31 million miles of the planet Jupiter, which has also been known to “chew up comets,” Slooh said, due to its intense gravitational field.
“It certainly feels like it’s only a matter of time before comet 73P is destroyed, disintegrating into a trail of cosmic dust.” said Cox.
Comet 45P/Honda-Mrkos-Pajdušáková – which swept closest to Earth on February 11, 2017, temporarily becoming the most famous comet that practically nobody saw.
Its closest point was around 8 UTC at which time the comet was 0.08 AU (7.4 million miles, about 12 million km, or some 30 times the moon’s distance) from the Earth.
The estimated brightness of Comet 45P/Honda-Mrkos-Pajdušáková at its closest and brightest was magnitude +7.
That’s well outside the limit for visibility with the unaided eye. What’s more, a diffuse object, like a comet, is even tougher to see at that magnitude, or any magnitude. The comet is still around, but an extremely dark sky and optical aid (at least binoculars, probably a telescope) are needed to see it.