Comet 46P/Wirtanen could be the source of a new meteor shower on Earth

2023-12-11 18:08:45

According to a French team of astronomers, a new meteor shower might take place this Tuesday, December 12. Our planet is preparing to pass through a cloud of debris left by comet 46P/Wirtanen as it approaches the Sun.

A cloud of debris left around the Sun by a comet named 46P/Wirtanen might enter the Earth’s atmosphere and trigger a new meteor shower this Tuesday, according to a team of scientists led by astronomer Jérémie Vaubaillon of the Paris Observatory -PSL. “Results show a possible meeting scheduled for December 12, 2023, between 8:00 and 12:30 UT”i.e. between 9:00 a.m. and 1:30 p.m. (Paris time), indicate the researchers, whose results must be published soon in the journal Astronomy & Astrophysics.

Unfortunately, in our latitudes, the Sun will already have risen in Europe. “Overall, the most optimal observations on the planned day would be from eastern Australia, New Zealand and Oceania”underlines the team on the scientific pre-publication site arXiv. Shooting stars will appear to come from the star Lambda-Sculptor, located in the Sculptor constellation. Therefore, this new meteor shower might be called “Sculptorides”, according to the site Space.comwhich reminds us that these phenomena are named following the objects in the sky from which the most intense flow comes.

A small comet well known to astronomers

Discovered in 1948 at the Lick Observatory in California (United States) by astronomer Carl Alvar Wirtanen (hence its name), 46P/Wirtanen is a small comet. Its core is barely 750 m in diameter. It speeds through the cosmos at a speed of 38 kilometers per second and completes its revolution in 5.4 years. And her glow grows stronger every time she comes back around. Out of twelve of its successive passages at perihelion (the closest point to the Sun), it has been observed eleven times in the past. The last time was December 16, 2018.

That year, the hairy star flew past our planet at a distance of 7 million kilometers, so much so that it might be seen with the naked eye. 46P/Wirtanen, whose orbit is influenced by Jupiter, might one day be ejected outside the Solar System. Such an event might occur in twenty-five years, if astronomers are to be believed. Before leaving us forever, the hairy star will make a final flyby as close as possible to Earth. The traces of its passage around the Sun will remain for millennia, including following its departure.

How are meteor showers formed?

Indeed, meteor showers are formed when our planet passes through clouds of debris left by a comet at the time of its perihelion, that is to say the point of its orbit closest to the Sun. Unlike asteroids, which orbit between Jupiter and Mars, comets come from much further away, most of them well beyond the planet Neptune. These regions further from the Sun are colder. And comets therefore contain more ice than their asteroid cousins.

As it approaches the Sun, under the effect of radiation from our star, the solid materials of the comet are then transformed into gas by a process known as “sublimation”. When this gas bursts from the icy outer shell and escapes from the comet, it releases debris which forms its “tails”. The debris it leaves behind sometimes forms clouds that the Earth then passes through approximately every year at the same time during its journey around the Sun. Fragments then enter the atmosphere, creating these famous fleeting light trails in the sky.

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As for the new meteor shower scheduled for Tuesday, December 12, “the observations will be difficult due to the low entry velocity and relatively small size of the meteoroids.”warns the team of scientists from the Paris-PSL Observatory. “Nevertheless, we strongly encourage meteor enthusiasts to make scientific observations and send their reports to the International Meteor Organization (IMO)”, they emphasize. Small consolation, another meteor shower, the famous Geminids, will reach its peak around the same time, on the nights of December 13 and 14.

Matthieu DELACHARLERY

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