Decoding a meteorite
On June 6, 2017, residents of Mukundpura village near Jaipur saw a bright trail in the sky followed by a thunderous sound. They spotted a burning object with a sulphur smell on the soft agricultural land.
- The meteorite broke into several fragments, but a pit of about 15 cm in diameter and 10 cm in depth was formed at the impact site.
- The meteorite named Mukundpura CM2 was classified to be a carbonaceous chondrite.
- This is a type of stony meteorite, considered the most primitive meteorite and a remnant of the first solid bodies to accrete in the solar system.
- The composition of carbonaceous chondrites are also similar to the Sun.
- Meteorites are broadly classified into three groups – stony (silicate-rich), iron (Fe–Ni alloy), and stony-iron (mixed silicate–iron alloy).
- Chondrites are silicate-droplet-bearing meteorites, and this Mukundpura chondrite is the fifth carbonaceous meteorite known to fall in India.
Degrees of alteration
- The study revealed that Mukundpura CM2 had experienced varying degrees of alteration during the impact.
- Some minerals like forsterite and FeO olivine, calcium aluminium rich inclusion (CAI) minerals escaped alteration.
- Few magnetites, sulphides and calcites were also found.
- Detailed spectroscopic studies revealed that the meteorite had very high (about 90%) phyllosilicate minerals comprising both magnesium and iron.
- Further X-ray studies showed it also had aluminium complexes.
Relevance to asteroids
- The Mukundpura CM2 study are relevant to the surface composition of near-Earth asteroids Ryugu and Bennu.
- In October 2020, NASA’s OSIRIS-REx mission collected samples from Bennu and is expected to return in September 2023.
- Last month, Japan’s Hayabusa-2 mission landed on Earth with samples from Ryugu.
- Infrared spectroscopy results suggest that spectral properties of the surface of these asteroids are consistent with CM carbonaceous meteorites.
- Therefore, a better understanding of the nature and evolution of such meteorites that have been aqueously altered will help considerably in the interpretation of results of these missions.
Early solar system
- Meteorites are representative of asteroids. Asteroids are the remnant debris of the inner solar system formation process and thus offer the formation history or the building blocks of the planets.
- Therefore, by studying meteorites in the laboratory and asteroids by exploration and sample return mission we try to reconstruct the activity of early solar system events.
- Also, asteroids are often rich in volatiles and other minerals and can be exploited for future planetary exploration.