ISRO: Chandrayaan-2 orbiter detects Argon-40 on Lunar exosphere

Chandra’s Atmospheric Composition Explorer-2 (CHACE-2) paylo aboard Chandrayaan-2 orbiter has detected Argon-40 from an altitude of approximately 100 km said ISRO on Thursday. Planetary scientists prefer to call thin gaseous envelope around Moon as ‘Lunar exosphere’ since it is so tenuous that gas atoms very rarely collide with each or. ISRO also released a schematic of how Argon-40 is formed.

RE | Chandrayaan-2: NASA takes new pictures of Vikram Lander's landing site

An important constituent of lunar exosphere

Argon-40 (⁴⁰Ar), which is one of isotopes of ble gas Argon, is an important constituent of lunar exosphere. It originates from rioactive disintegration of Potassium-40 (⁴⁰K), which has a half-life of ~1.2 X 10⁹ years. rioactive ⁴⁰K nuclide, which is present deep below lunar surface, disintegrates to ⁴⁰Ar, which, in turn, diffuses through intergranular and makes way up to lunar exosphere through seeps and faults.

RE | Chandrayaan 2 observes "impact craters" on Moon's surface: ISRO

CHACE-2 is a neutral mass spectrometer

Chandra’s Atmospheric Composition Explorer-2 (CHACE-2) paylo aboard Chandrayaan-2 orbiter, is a neutral mass spectrometer-based paylo which can detect constituents in lunar neutral exosphere in range of 1-300 amu (atomic mass unit). As part of its early operation, it has detected ⁴⁰Ar in lunar exosphere from an altitude of ~100 km, capturing day-night variations of concentration. ⁴⁰Ar being a condensable gas at temperatures and pressures that prevail on lunar surface, condenses during lunar night. After lunar dawn,  ⁴⁰Ar starts getting released to lunar exosphere.

RE | Chandrayaan-2: NASA takes new pictures of Vikram Lander's landing site

Impact craters on south polar region of moon

On October 22, ISRO released pictures of impact craters on  south polar region of moon ed by orbiter of Chandrayaan 2. se pictures show observations me by  Syntic Aperture Rar on lunar surface. Moon’s surface has a lot of impact craters owing to  continuous bombardment of celestial bodies, se craters are usually studied by a powerful remote sensing instrument to kw more about moon’s surface. 

RE | Russia, UAE all praise for ISRO post losing contact with lander