Pluto, the dwarf planet continues to remain the center of attraction for astronomers throughout the world. An international team of astronomers, including from India, has successfully derived the accurate value of Pluto’s atmospheric pressure at its surface.
The atmospheric pressure on Pluto is 80,000 times less than Earth’s atmospheric pressure at mean sea level.
This pressure was calculated by observation of a stellar occultation by Pluto using a 3.6-m Devasthal optical telescope (DOT). It is India’s largest optical telescope and it also used the 1.3-m Devasthal Fast Optical Telescope (DFOT) telescopes located at Devasthal, Nainital.
The team has scientists from Aryabhatta Research Institute of Observational Sciences (ARIES). They used signal-to-noise ratio light curves from the sophisticated instruments to reach an accurate value of Pluto’s atmospheric pressure at its surface.
Besides, astronomers used data from 12 occultations. These 11 events took place between 1988 to 2016; it shows a three-fold monotonic increase of pressure during that period.
The research was published in the Astrophysical Journal Letters. Since mid-2015, Pluto’s atmosphere is in a plateau phase.
These new observations also confirm that Pluto suffers intense seasonal episodes; a large depression known as Sputnik Planitia is responsible for the same.
Meanwhile, its poles remain in permanent sunlight or darkness over its 248-year-long orbital period.
This is what leads to strong effects on its Nitrogen (N2) atmosphere, mainly controlled by vapour pressure equilibrium with the surface N2 ice.
Astronomers observe that Pluto is now moving away from the Galactic plane as seen from Earth . Moreover, the stellar occultations by Pluto are becoming increasingly rare.
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