Rare blue asteroid sometimes behaves like a comet (earthsky.org)
By Eleanor Imster in Space | November 1, 2018
Astronomers caught a glimpse of Phaethon – the bizarre blue asteroid responsible for the Geminid meteor shower – and found it even more enigmatic than they’d thought.
Blue asteroids are rare, and blue comets are almost unheard of. An international team of astronomers investigated 3200 Phaethon, a bizarre blue asteroid that sometimes behaves like a comet, and found it even more enigmatic than they’d previously thought.
On December 16, 2017, the asteroid made its closest approach to Earth since 1974, passing within 6.4 million miles (10.3 million km). The team analyzed data from the flyby from several telescopes around the world to learn more about the mysterious object which has puzzled astronomers since its discovery in 1983. The researchers presented the results of their study on October 23, 2018, at the annual meeting of the American Astronomical Society’s Division for Planetary Science in Knoxville, Tennessee.
Blue asteroids, which reflect more light in the blue part of the spectrum, make up only a fraction of all known asteroids. A majority of asteroids are dull grey to red, depending on the type of material on their surface.
Phaethon sets itself apart for two reasons: it appears to be one of the bluest of similarly-colored asteroids or comets in the solar system; and its orbit takes it so close to the sun that its surface heats up to about 1,500 degrees Fahrenheit (800 degrees C), hot enough to melt aluminum.
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more: https://earthsky.org/space/rare-blue-asteroid-phaeton-fly-by?utm_source=EarthSky+News