Potentially dangerous asteroid Phaeton behaves 'strangely': It began to rotate faster around its axis

October 17, 2022  13:55

Asteroid 3200 Phaeton is about 5.4 km in diameter. This is one of the largest asteroids approaching the Earth, and therefore it is considered to be potentially dangerous for our planet.

Recently, scientists have noticed that the asteroid began to behave "strangely": 3200 Phaeton began to rotate faster and faster around its axis - every year its rotation period is reduced by 4 milliseconds. It may seem that this is not such a big difference, but the fact is that usually the rotation speed of asteroids does not change at all.

Unusual behavior of 3200 Phaeton

Japan's aerospace research agency JAXA plans to send the DESTINY+ research mission to asteroid Phaeton in 2024. The agency's probe is scheduled to fly past the asteroid in 2028.

In the run-up to the mission, this asteroid is being studied particularly closely, and because of this, a team of scientists led by the Arecibo Observatory and the University of Central Florida have noticed the asteroid's unusual behavior.

Based on observations from 1989 to 2021, researcher Sean Marshall of the Arecibo Observatory in Puerto Rico created a model to study the asteroid before the DESTINY+ mission started. However, it soon became clear that the predictions made on the basis of calculations do not correspond to real data. For example, the maximum brightness of the asteroid is not observed at the time that was predicted by the calculations. The scientist suggested that the discrepancy between theory and practice can be explained by a change in the rotation speed of the asteroid. Perhaps this occurred as a result of a collision or "interaction" of the asteroid with any comet in December 2020.

phaeton-rotation.jpg (121 KB)

So, according to scientists, the asteroid makes one rotation around its axis in 3.6 hours. However, as noted above, its rotation period is shortened by about 4 milliseconds per year. Even such a small change could affect DESTINY+ observations. To calculate the location of the asteroid when the spacecraft passes it, experts need to know its exact rotation speed.

If we can figure out why Phaeton behaves this way, it could give us new insight into the class of asteroids considered "potentially dangerous" that pass by Earth during its rotation around the Sun.

Note that the rotation speed of asteroids does not normally change. So far we know about only 11 cases (the 11th is Faeton), when the previously recorded indicators of the asteroid have changed.

How dangerous is 3200 Phaeton to us?

According to scientists, a collision with asteroid 3200 Phaeton is not expected in the foreseeable future. It is considered potentially dangerous to Earth because of its large size and the fact that it approaches us close enough.

phaeton

But, perhaps, scientists will have to revise their views on the degree of danger of this asteroid - in light of new data on the change in the speed of its rotation around its axis.

It is known that in the XXI century, the asteroid will approach the Earth several times: it will happen in 2050, 2060 and 2093. It also approached our planet on December 10, 2007 (it flew past at a distance of 18.1 million km) and on December 16, 2017 (it flew past at 10.31204 million km, which is equal to 27 distances to the Moon).

What is known about 3200 Phaeton?

3200 Phaeton is considered a Palladian asteroid with a "stone comet" orbit. Its orbit is extremely elongated, so it crosses the orbits of Mercury, Venus, Earth and Mars during its rotation around the Sun. The asteroid is named after Helios, the son of the sun god in Greek mythology, because during its rotation, it flies very close to the Sun.

It is this asteroid that is "responsible" for the Geminids meteor shower, which we can observe every year during the first half of December, and which is considered to be one of the most powerful meteor showers.

geminides

According to experts, several thousand years ago, asteroid 3200 Phaeton left behind a dusty trail, which is actually responsible for the Geminids. This makes Geminides a unique phenomenon, since most meteor showers come from the dust of a comet, not from an asteroid.

As the Earth revolves around the Sun, each December it crosses Phaeton's orbital path, flying through the dust and small rocks left behind by the asteroid. 

These rocks may be the size of a grain of sand, but they burn up in Earth's atmosphere and emit bright flashes of light.

Interestingly, Phaeton is one of only two asteroids known to us to be associated with meteor showers.


 
 
 
 
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