Ca-Al-rich inclusions

Ca-Al-rich inclusions (CAIs) are inclusions found in carbonaceous chondrites. These inclusions are about 1 cm (0.39 in) long. They are light-colored and made of calcium and aluminum. High-temperature minerals are often found in CAIs. These objects are among the first solid objects to be created by the cooling of a protoplanetary disk. CAIs are formed at much higher temperatures than the associated chondrules. They may have survived many high-temperature events while most chondrules are created in a single melting event.

The isotopic anomalies of CAIs give important information about the creation of the solar system. The studying of them suggests that the solar nebula collapsed soon after a nearby supernova. Radiometric dating shows that the CAIs formed about 2 million years before the chondrules formed.

References

• Gilmour J. 2002. The Solar System's first clocks Science 297, 1658-1659. Archived 2016-03-03 at the Wayback Machine
• Amelin Y. et al. 2002. Lead isotopic ages of chondrules and calcium-aluminum-rich inclusions Science, 297, 1678-1683.
• Krot A.N. 2002. Dating the earliest solids in our Solar System. Planetary science research discoveries. http://www.psrd.hawaii.edu/Sept02/isotopicAges.html
• Shukolyukov A. & Lugmair G.W. 2002. Chronology of asteroid accretion and differentiation 687-695, in Bottke W.F. et al. (eds) Asteroids III. University of Arizona Press. ISBN 0-8165-2281-2