Atmosphere of Pluto

Atmosphere of Pluto
Pluto
Departure shot of Pluto by New Horizons, showing Pluto's atmosphere backlit by the Sun. The blue color is close to what a human eye would have seen, and is caused by layers of haze in the atmosphere
General information
Height~1 700 km (exobase)[1]
Average surface pressure1.0 Pa (9.87×10−6 atm) (2015)[2]
0.91 Pa (8.98×10−6 atm) (2020)[3]
Composition[a]
Nitrogen (N
2)		>99%
Methane (CH
4)		0.25%
Carbon monoxide (CO)~0.0515%
Acetylene (C
2H
2)		0.0003%
Ethylene (C
2H
4)		0.0001%
Hydrogen cyanide (HCN)10-5-10-6%

The atmosphere of Pluto is the layer of gasses that surround the dwarf planet Pluto. It consists mainly of nitrogen (N2), with minor amounts of methane (CH4) and carbon monoxide (CO), all of which are vaporized from surface ices on Pluto's surface. It contains layered haze, probably consisting of heavier compounds which form from these gases due to high-energy radiation. The atmosphere of Pluto is notable for its strong and not completely understood seasonal changes caused by peculiarities of the orbital and axial rotation of Pluto.[6]

The surface pressure of the atmosphere of Pluto, measured by New Horizons in 2015, is about 1 Pa (10 μbar), roughly 1/100,000 of Earth's atmospheric pressure. The temperature on the surface is 40 to 60 K (−230 to −210 °C),[6] but it quickly rises with altitude due to a methane-generated greenhouse effect. Near the altitude of 30 km it reaches 110 K (−163 °C), where it then slowly decreases afterwards with height.[7]

Pluto is the only trans-Neptunian object with a known atmosphere.[7] Its closest analog is the atmosphere of Triton, although in some aspects it resembles even the atmosphere of Mars.[8][9]

The atmosphere of Pluto has been studied since the 1980s by way of earth-based observation of occultations of stars by Pluto[10][11] and spectroscopy.[12] In 2015, it was studied from a close distance by the spacecraft New Horizons.[4][2]

  1. ^ Cite error: The named reference Strobel2017 was invoked but never defined (see the help page).
  2. ^ a b Cite error: The named reference Gladstone_2016 was invoked but never defined (see the help page).
  3. ^ Cite error: The named reference Farahani2021 was invoked but never defined (see the help page).
  4. ^ a b Cite error: The named reference Stern_2015 was invoked but never defined (see the help page).
  5. ^ Cite error: The named reference Lellouch_2017 was invoked but never defined (see the help page).
  6. ^ a b Cite error: The named reference Stern_2014 was invoked but never defined (see the help page).
  7. ^ a b Cite error: The named reference Dias_Oliveira_2015 was invoked but never defined (see the help page).
  8. ^ Cite error: The named reference Lellouch_2015 was invoked but never defined (see the help page).
  9. ^ Cite error: The named reference Johnston_2006 was invoked but never defined (see the help page).
  10. ^ Cite error: The named reference Elliot_2007 was invoked but never defined (see the help page).
  11. ^ Cite error: The named reference Olkin_2015 was invoked but never defined (see the help page).
  12. ^ Cite error: The named reference Yelle_1997 was invoked but never defined (see the help page).


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