William Atkins
Friday, 18 September 2009 20:22
Science -
Space
Page 2 of 3
The astronomy team believes that the meteorite started out as part of an asteroid in the innermost main asteroid belt between Mars and Jupiter. The orbit of the meteorite gradually evolved into one that went around the Sun.
A picture of the meteoroid flying through the night sky is found on the CSIRO
website(September 18, 2009), which states,
“All-sky image from the easternmost station in the Desert Fireball Network showing the track of the fireball on the left.”
The same website also shows the meteorite, called “Bunburra Rockhole” (BR) after it landed on Earth in July 2007. [“
Bunburra Rockhole (BR), the meteorite, at the discovery site”]
Their abstract goes on to state,
“The great majority of basaltic meteorites are derived from the asteroid 4 Vesta. We report on a recent fall that has orbital properties and a oxygen isotope composition that suggest a distinct parent body. Although its orbit was almost entirely contained within Earth’s orbit, modeling indicates that it originated from the innermost main belt.”
“Because the meteorite parent body would likely be classified as a V-type asteroid, V-type precursors for basaltic meteorites unrelated to Vesta may reside in the inner main belt. This starting location is in agreement with predictions of a planetesimal evolution model that postulates the formation of differentiated asteroids in the terrestrial planet region, with surviving fragments concentrated in the innermost main belt.”
The meteorite is said to be rare in composition because it is composed of basaltic igneous rock.
Astronomers think these rare meteorites first formed very near to the Sun, but later scattered about further out in the solar system, most of them in the main asteroid belt.
Asteroids, and the meteoroids they expel out, are believed to have helped to form the planets that today exist in the solar system. Consequently, they are important to study in order to learn more about the origins of the solar system.
As a note: A meteoroid is one that is found in outer space, while the same object is called a meteor while it enters Earth’s atmosphere and, if it survives its journey and lands on Earth, it is then called a meteorite.
Page three concludes with comments from one of the authors of the study.
