[meteorite-list] New Study Sheds Light on Origin of Most Common Meteorites

[Ron Baalke]

https://www.psi.edu/news/sanchez

New Study Sheds Light on Origin of Most Common Meteorites
Planetary Science Institute
Aug. 5, 2015
 
Tucson, Ariz. -- For decades astronomers debated the source of the most 
common type of meteorites that fall on Earth called H ordinary chondrites. 
A new study by researchers at the Planetary Science Institute sheds some 
light on the origin of these meteorites in the main asteroid belt between 
Mars and Jupiter.
 
"H-chondrites make up 33 percent of all the meteorites that fall on Earth, 
yet their origin has been the source of debate for the last few decades. 
We have now added an important piece to this puzzle that will contribute 
to resolve this debate," said Juan Sanchez, an associate research scientist 
at PSI who is the lead author of a paper published in The Astrophysical 
Journal. 
 
H ordinary chondrites have been traditionally linked to (6) Hebe, a large 
asteroid located in the inner part of the main asteroid belt. This study, 
however, shows that some of these meteorites might have originated in 
a more distant region of the main belt.
 
The team of astronomers, which included PSI researchers Vishnu Reddy and 
Lucille Le Corre, studied minerals on the surface of a near-Earth asteroid 
named (214869) 2007 PA8 using the NASA Infrared Telescope Facility (IRTF) 
on Mauna Kea, Hawaii during its close approach to Earth during November 
2012. These observations showed that H ordinary chondrite meteorites came 
from an asteroid similar to 2007 PA8. 
 
2007 PA8, like all near-Earth asteroids, comes from the main asteroid 
belt. However, its orbit places the origin of this object in the outer 
regions of the main belt. 
 
"The fact that a near-Earth asteroid with this orbit has a composition 
similar to H-chondrites suggests that some of these meteorites might not 
be related to (6) Hebe, nor originated in the inner part of the main belt," 
Sanchez said. 
 
"Moreover, it allows us to link H-chondrites to some specific asteroid 
families in the outer part of the main belt. Our study shows that the 
Koronis family is the most likely source region for 2007 PA8, and possibly 
the source for some of the H-chondrites that fall on Earth," he said.
 
The research is funded by a grant to PSI from NASA's Near Earth Object 
Observations program.