NASA spotted a mysterious six-tailed object in our Solar System using the Hubble Space Telescope on September 10, then caught another glimpse of it on September 23. The object, an asteroid named P/2013 P5, behaved in a strange manner that had never been documented before. The asteroid spun rapidly, and shot out jets of itself that caused it to move, somewhat like a pinwheel firework that’s gone out of control.
Somewhere between Jupiter and Mars, P/2013 P5 lurks in what is often called the main asteroid belt, and it appears to be rocketing about erratically under its own power. The behavior of the asteroid has been puzzling scientists ever since it was first detected by NASA, though some ideas are developing about what is causing P/2013 P5 to act differently from any other known asteroid.
According to David Jewitt, a professor in the Department of Earth and Space Sciences at the University of California in Los Angeles, one idea was that there was ice on the asteroid, and it was “outgassing.”
However, the professor noted that P/2013 P5 was “too hot, around 170 Kelvin, for ice.” Also, a collision with the asteroid was suggested; but, that wouldn’t cause it to have six plumes of matter spewing from it, just one.
The current theory is that the asteroid is breaking apart because it’s spinning too rapidly, and the spin might be due to eons of being bombarded by solar emissions.
How can emissions from the Sun move objects like asteroids?
All stars — of which our Sun is one — shoot out radiation and protons, and if these particles hit asteroids, sometimes this bombardment will cause them to rotate. Eventually, as the pressure from these solar emissions is constant and there is practically no friction in space, the rate the asteroids spin at increases and they spin about ejecting matter and falling apart until they are completely destroyed.
This theory is called the Yorp effect. It’s an acronym for the four scientists (Yarkovsky, O’Keefe, Radzievskii, and Paddack) who suggested that the reason there were not very many asymetrical objects in space is because they spun so rapidly due to solar emissions that they would break apart over time.
What NASA is observing with P/2013 P5 is that the theory might have a strong basis to it, but more irregular-shaped asteroids need to be detected and observed before the theory can be confirmed.
Professor Jewitt thinks that other asteroids which behave in a similar manner will, eventually, be observed. As he noted, P/2013 P5 is “almost certainly the first of many more to come.”
Though the shape of P/2013 P5 has changed, because it’s losing matter, it will likely be around for quite a while to come. Since the time it was discovered, only a tiny fraction of the asteroid has been destroyed. The nucleus of P/2013 P5 is 1,400 feet wide, so unless its rate of spin increases even more rapidly, or it collides with another object, scientist will have many more years to develop further theories about it.
Professor Jewitt has written and published a research paper on the peculiar-acting asteroid, P/2013 P5, in November’s issue of Astrophysical Journal Letters.
Maybe because scientists at NASA, using the Hubble Space Telescope, discovered the asteroid with six tails known as P/2013 P5, one day a chapter in an astronomy textbook will mention it, and the tale of how it helped prove the YORP theory that four scientists lent their initials to, in their attempt to explain why there are few asymmetrically-shaped objects in space.
Written by: Douglas Cobb