There鈥檚 a new type of asteroid, and it鈥檚 spinning so fast it鈥檚 falling apart. A small asteroid has been throwing off rocks for at least 6 years, the most activity we鈥檝e ever seen from a rock of its type.
Generally there are two reasons for an asteroid to blow off material: either something has hit it, or it has ices or elements called volatiles, including water, that turn into gas and blow away when the asteroid gets warm.
But (6478) Gault, a rock about 4.5 kilometres across that orbits the sun every 3.5 years, seems different. As far as we can tell, it doesn鈥檛 have any volatiles, and when Colin Orion Chandler at Northern Arizona University and his colleagues examined data from 2013 to now from the National Optical Astronomy Observatory, they found signs of activity in every picture of it.
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In all the pictures, (6478) Gault has a comet-like tail of material behind it, so it appears to be constantly shedding debris 鈥� the first asteroid of its type that we鈥檝e seen doing so more than once. 鈥淭his has been happening for a long time, in multiple orbits around the sun and at different distances from the sun,鈥� says Chandler. 鈥淚t鈥檚 a really weird object no matter how you look at it.鈥�
He says that this may be due to a phenomenon called the YORP effect, in which sunlight hits the angled side of an asteroid and makes it spin. The faster spin makes the rock shed dust and debris. Eventually, it will probably fall apart completely.
鈥淚f this is a type of object that can mimic something that has water, we need to know why that happens and how it works so we can distinguish between things that have water and things that don鈥檛,鈥� says Chandler. Figuring out exactly what鈥檚 going on with it may help eventual asteroid miners rule out rocks like this as targets when looking for water and other volatiles in space.
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