ISRO Chandrayaan-2 Payload Detects Argon-40 On Lunar Exosphere

ISRO Chandrayaan-2 orbiter has detected the Argon-40, which is one of the isotopes of the noble gas Argon. The Argon-40 is an important constituent of the lunar exosphere and has been detected by Chandrayaan-2's CHACE-2 payload from roughly 100km altitude, ISRO updated from its official Twitter handle.

Chandrayaan-2 CHASE-2 Detects Argon-40

The Chandrayaan-2 is equipped with the Chandra's Atmospheric Composition Explorer-2 or the CHACE-2 payload. It is a neutral mass spectrometer-based payload with the capability of detecting constituents in the lunar neutral exosphere. As part of Chandrayaan-2 CHACE-2's initial operation, the payload has detected Argon-40 and has also captured the day-night variations of concentration.

ISRO notes that the Argon-40 gas is a condensable one at the temperatures and pressures in the lunar surface/environment. The CHACE-2 has noted that the Argon-40 gas condenses during a lunar night and begins to release in the lunar exosphere as lunar dawn starts.

Chandrayaan-2 CHACE-2 In Lunar Exosphere

The Chandrayaan-2 with the CHACE-2 is a piece of important equipment to help understand the lunar exosphere. "Planetary scientists prefer to call the thin gaseous envelope around the Moon as the 'Lunar exosphere' since it is so tenuous that the gas atoms very rarely collide with each other," ISRO states in the latest report.

In further comparison, ISRO elaborates that the Earth's atmosphere, near the mean seal level, contains approximately 1019 atoms in a cubic centimeter of volume. On the other hand, the Moon's exosphere contains roughly 104 to 106atoms in a cubic centimeter, which shows the massive gap in the exosphere.

ISRO Chandrayaan-2 Findings

This further brings us to understanding the presence of Argon-40. The Indian Space Research Organisation notes that the Argon-40 originates from the radioactive disintegration of Potassium. The radioactive Potassium nuclide in the deep lunar surface then disintegrates into Argon-40 and "diffuses through the intergranular space and makes way up to the lunar exosphere through seepages and faults," ISRO explains.

Apart from the CHACE-2's Argon-40 finding, the ISRO Chandrayaan-2 has also helped find other important discoveries on the lunar surface. Earlier this month, ISRO released images of the moon's surface clicked by Orbiter High-Resolution Camera (OHRC) aboard Chandrayaan-2 to help understand it for future explorations.