A rare and spectacular meteor shower will unfold over New Zealand skies later this year, when dust and debris from a well-known comet collides with Earth’s atmosphere.
Scientists have described the December 12 event as “really unusual” and the first time that a debris shower from the Comet 46P/Wirtanen1 will be widely observable overhead.
Meteor showers occur when multiple space rocks, or meteorites, enter our atmosphere at high speed at once and burn up, appearing as shooting stars or fireballs.
While meteor showers aren’t uncommon in our skies – there’s more than a dozen that can be seen here throughout the year – December’s occurrence promised to be unique.
Dr Jeremie Vaubaillon, of France’s Paris Observatory, explained the debris stemmed from the 1.2km-wide, short-period comet 46P/Wirtanen1, which orbited the Sun once every 5.4 years – much faster than the 75-year orbit of the better known Halley.
Four years ago, it made one of its closest approaches of Earth in 70 years, coming within 12,000km of our planet.
Back in 1974 and 1980, as the comet passed close to Jupiter, its debris was pushed onto a collision course with Earth – and Vaubaillon calculated that it would finally arrive here on December 12.
“This is a really unusual event,” he said.
“We have modelled more than 50 years worth of debris clouds from this comet and December’s event will be the first time a collision should be widely observable.”
The event was also likely to be a one-off, as it’d be a long time before a debris cloud from this comet would be seen again soon.
“Since no meteor shower caused by comet 46P/Wirtanen has ever been seen before, we’re not quite sure how many meteors people will see.”
Here in New Zealand, a group of astronomers working under the Fireballs Aotearoa project were already preparing for the event.
“Over the last two years, Fireballs Aotearoa and its many volunteers have built an amazing network of meteor cameras covering most of New Zealand,” said the group’s co-founder, Otago University geologist Professor James Scott.
“We see loads of bright fireballs that drop meteorites, but our cameras also record and classify a whole range of meteor showers.”
Scott said the meteor shower – expected between 9pm and midnight on December 12 - should be visible to the eye.
“But there’s still time to get involved if people want to build or install their own fireball camera,” he said.
Royal Astronomical Society of NZ president Nalayini Davies was also looking forward to the big event.
“The new meteor shower happens at the same time as the Geminids, one of the main annual meteor showers,” she said.
“The Geminids will be going faster and from a different direction, so I’m hoping that all of New Zealand gets a clear night and a good show from both meteor showers.”
Vaubaillon said good observations of the event would help him and his colleagues better understand meteors and comets.
“The sizes of the meteors tells us about the distribution of particle sizes in comet 46P/Wirtanen,” he said.
“It’s hard to sample comets directly, even with spacecraft, so we hope to learn a lot from the New Zealand meteor observations.”
The forecast comes just days after much of the country was treated to a fireball show caused by an incoming meteor estimated at some 4.56 billion years old.
Scott and his colleagues were now hunting for its remains, which likely landed in the north of the Waitaki River in Otago.