BIZARRE! NASA reveals this strange asteroid's comet-like tail is not dust, but GAS

An asteroid has sprouted a comet-like tail.

| Updated on: Apr 27 2023, 21:09 IST
Where do comets come from?
1/6 Most comets come from the Kuiper belt, a region beyond the orbit of Neptune comets from this neighborhood usually take 200 years or less to make one orbit around the sun. These are called short-period comets. (NASA)
2/6 Comets also come from their other hangout Oort cloud, a far-far-distant cloud, sending some flying into the inner solar system. (Pixabay)
3/6 When they are at home in the Oort cloud or Kuiper belt comets are just dull, dark chunks of ice, dust, and rock. In this state, they may not be much different from asteroids. (NASA/MSFC/Aaron Kingery)
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4/6 Sometimes the gravitational pull of a planet can disturb comets in the Kuiper Belt and fly one headlong toward the sun. Notably, Jupiter's strong gravity can turn a long-period comet into a short-period one. (NASA)
5/6 The Sun's gravitational pull takes over, shaping the comet's path into an elliptical orbit. The comet travels faster and faster as it nears the sun swings and goes around close to the backside, then heads back to more or less where it came from. (Pixabay)
image caption
6/6 What makes comets look fuzzy and have tails? As comets get closer to the sun and begin to warm up, some of their materials start to boil off. This material forms a cloud around the nucleus. The cloud is called the coma and may stretch over hundreds of thousands of miles across. (NASA)
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A weird asteroid has a comet-like tail. (NASA/JPL-Caltech/IPAC)

Asteroids are mostly rocky and airless remnants left over from the early formation of our solar system. On the other hand, Comets are a mix of ice and rock. One of the interesting facts about comets is that they do form tails as the Sun vaporizes their ice and it blasts off material and leaves a trail along their orbits. Contrarily, due to their rocky nature, asteroids do not form such tails.

However, weirdly, there is a bizarre asteroid named 3200 Phaethon which acts just like a comet! NASA has revealed that asteroid 3200 Phaethon "brightens and forms a tail when it's near the Sun, and it is the source of the annual Geminid meteor shower." So far, scientists have blamed this behaviour due to the escape of dust from the asteroid while coming closer to the Sun. Surprisingly, the latest study using two NASA solar observatories has helped to indicate that instead of dust, Phaethon's tail is primarily composed of sodium gas.

About asteroid 3200 Phaethon

In 1983, the discovery of Phaethon by astronomers led to the realization that the asteroid's orbit was in alignment with that of the Geminid meteors. Despite being an asteroid and not a comet, this discovery pointed toward Phaethon as the source of the annual meteor shower.

As Phaethon approached its closest point to the Sun in 2009, NASA's Solar Terrestrial Relations Observatory (STEREO) detected a short tail emanating from the asteroid. This supported the notion that dust was being released from the asteroid's surface due to the Sun's heat.

However, in 2018, a solar mission imaged part of the Geminid debris trail and made an unexpected discovery. The observations from NASA's Parker Solar Probe showed that the trail contained a significantly larger amount of material than Phaethon could have shed during its close approaches to the Sun.

What makes this asteroid behave like a comet?

The latest paper in the Planetary Science Journal, led by Qicheng Zhang, a PhD student at the California Institute of Technology, suggested that the close encounter of the asteroid Phaethon with the Sun led to the vaporization of the sodium within the asteroid and drive comet-like activity.

The researchers used the Solar and Heliospheric Observatory (SOHO) spacecraft — a joint mission between NASA and the European Space Agency (ESA) – which has colour filters that can detect sodium and dust. This evidence indicates that Phaethon's tail is made of sodium, not dust.

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First Published Date: 27 Apr, 21:09 IST