Comet 46P/Wirtanen on Dec. 12, 2018.
(Image credit: Wikimedia Commons/Stub Mandrel)
Earth may experience an entirely new meteor shower this December when our planet enters a stream of the debris left around the sun by a near-Earth comet. These meteors will appear to stream from the direction of the star Lambda-Sculptoris, meaning a potential name for this meteor shower is the “Lambda-Sculptorids.”
The progenitor of the potential new meteor shower is Comet 46P/Wirtanen, which was discovered in 1948 and orbits the sun every 5.4 years, much more rapidly than other comets, such as Halley’s Comet — which takes around 75 years to orbit our star.
A team of scientists led by Observatoire de Paris astronomer Jeremie Vaubaillon wanted to answer the question of why Earth hasn’t experienced a meteor shower created by debris from Comet 46P/Wirtanen before. What they discovered is that such an event is due to occur on Tuesday, Dec. 12, 2023.
“The results show a possible encounter forecast for Dec. 12, 2023, between 8:00 and 12:30 UT [0300 and 0730 EST]. The activity level of the shower is highly uncertain due to the absence of reported past showers,” they write in a paper discussing their results published on the open-source arXiv repository and set for publication in the journal Astronomy & Astrophysics. “Overall, the most optimal observations on the forecasted day would be achieved from Eastern Australia, New Zealand, and Oceania.”
Related: Meteor showers 2023: When is the next one?
Meteor showers are created when Earth passes through clouds of debris left behind by comets as they move close to the sun. As radiation from our star heats them, solid material within the comet turns straight into gas through a process called sublimation. As this gas erupts from the outer icy shell and escapes the comet, it blows debris free that forms the distinctive tails and auras — or “comas” — of these icy cosmic bodies.
This debris can also settle into streams around the sun that Earth then passes through at the same time roughly every year during our 365.3-day trip around our star. When that happens, fragments of debris enter Earth’s atmosphere at speeds as great as 162,000 miles per hour (260,713 kph) — or about 100 times faster than the top speed of a Lockheed Martin F-16 jet fighter. As they do, these fragments burn up high over Earth, creating steaks of light and larger pebble-sized fragments exploding as bright fireballs. This speed depends on a number of variables, including the angle at which fragments enter Earth’s atmosphere.
Meteors showers are named after objects in the sky from where the most intense bombardment seems to come. Thus, the Perseid meteor shower originates from debris left by the comet Swift-Tuttle that appears to stream to Earth from the constellation Perseus.
The roughly 1-mile-wide Comet 46P/Wirtanen is part of the Jupiter family of comets, which have orbits determined by the gravity of the gas giant and tend to orbit the sun with a period of less than 20 years. It last made a close approach to Earth on Dec. 16, 2018, coming to within around 7.22 million miles of our planet, at which time scientists discovered that it is a so-called “hyperactive comet,” which means it releases more water than would be expected for an icy body of the same size. Yet, no meteor showers have yet been associated with Comet 46P/Wirtanen.
To find out why this may be, the team used a variety of models to calculate the release of material from Comet 46P/Wirtanen, then calculated how these particles would behave after ejection and, thus, the type of stream of debris this would create. The team concluded that a meteoroid stream associated with this comet should have made contact with Earth several times in the past but that the low-velocity entry speed of debris into our planet’s atmosphere may have prevented meteor showers from manifesting.
“Several past encounters with the Earth and the stream were found, but no observations were reported to our knowledge. This is probably due to the quite unusual ejection velocity needed to bring large particles to the Earth,” the team wrote.
They discovered that Earth is due for an encounter with this stream in the very near future, possibly leading to the first recorded Lambda-Sculptorids meteor shower.
“The observation and subsequent report of this shower would be of tremendous scientific interest since it would put constraints on the size-frequency distribution of large particles for the comet,” the team concluded. “However, observations will be challenging due to the low entry velocity and the relatively small sizes of the meteoroids. Nevertheless, we strongly encourage meteor enthusiasts to perform scientific observations and send their reports to the International Meteor Organization (IMO).”
Another meteor shower, the well-known Geminids, are set to peak around the same time on the nights of Dec. 13 and 14.
If you want to try your hand at photographing the Geminids or any other meteor shower, be sure to check out our how to photograph meteors and meteor showers guide. And if you need imaging gear, consider our best cameras for astrophotography and best lenses for astrophotography.
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Robert Lea is a science journalist in the U.K. whose articles have been published in Physics World, New Scientist, Astronomy Magazine, All About Space, Newsweek and ZME Science. He also writes about science communication for Elsevier and the European Journal of Physics. Rob holds a bachelor of science degree in physics and astronomy from the U.K.’s Open University. Follow him on Twitter @sciencef1rst.