The most detailed telescope photographs to date of the asteroid Kleopatra – named after the ancient Egyptian queen – clearly show its odd “dog bone” shape, and astronomers say their studies may provide clues as to the solar system.
The latest observations of the asteroid, more than 125 million kilometers from Earth in the main asteroid belt between Mars and Jupiter, have allowed scientists to more accurately measure Cleopatra’s unusual shape and mass – and it s ‘turned out to be about a third lighter than expected, giving clues to its composition and formation.
“Asteroids are not inert bodies but complex geological mini-worlds,” said Franck Marchis, senior planetary astronomer at the SETI Institute in California and lead author of a new study on Cleopatra published this month in the journal Astronomy and Astrophysics. “Kleopatra and other weird asteroids are natural laboratories for challenging our knowledge of the solar system and getting us outside the box.”
Cleopatra was discovered in 1880 and takes its name from the original spelling of Cleopatra in the Greek alphabet. It is relatively large for an asteroid and has been observed by terrestrial telescopes for decades to determine its orbit around the sun. Its peculiar shape was only confirmed by radar about 10 years ago.
The latest photographs of the powerful Very Large Telescope at the European Southern Observatory in northern Chile provide more detail on its odd shape – with two large lobes connected by a thick “neck” so that it distinctly resembles a bone. .
Kleopatra is about 160 miles end-to-end – about the size of New Jersey – and weighs over 3.3 trillion tons. It spins about every five hours, and astronomers predict that if it spins much faster, its lobes could separate.
Marchis said Cleopatra’s unusual shape is a clue to her makeup. “It’s probably a loosely linked asteroid made from iron rubble,” he said in an email.
Researchers believe it may have formed from debris from an impact between larger asteroids that took place billions of years ago.
A team led by Marchis announced in 2008 that their observations showed Kleopatra also had two small moons, each a few miles in diameter, which they nicknamed Alexhelios and Cleoselene after two of the Egyptian queens’ children.
It is not uncommon for asteroids to have moons or form “binary systems” where two asteroids orbit each other. At least 15 asteroids in the main belt are known to have moons, and more than 400 pairs of orbiting asteroids have been found, Marchis said.
The latest observations have allowed astronomers to make detailed measurements of the moons’ orbits around Cleopatra, he said, suggesting that it is ancient conglomerates of rubble from the main asteroid – in in other words, Cleopatra could have “given birth” to her children.