Atmosphere of Mercury

Atmosphere of Mercury - nPa ). [2] The exospheric species...

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Atmosphere of Mercury Atmosphere of Mercury [1] Species CD, [n 1] cm −2 SD, [n 2] cm −3 Hydrogen (H) ~ 3 × 10 9 ~ 250 Molecular hydrogen < 3 × 10 15 < 1.4 × 10 7 Helium < 3 × 10 11 ~ 6 × 10 3 Atomic oxygen < 3 × 10 11 ~ 4 × 10 4 Molecular oxygen < 9 × 10 14 < 2.5 × 10 7 Sodium ~ 2 × 10 11 1.7–3.8 × 10 4 Potassium ~ 2 × 10 9 ~ 400 Calcium ~ 1.1 × 10 8 ~ 300 Magnesium ~ 4 × 10 10 ~ 7.5 × 10 3 Argon ~ 1.3 × 10 9 < 6.6 × 10 6 Water < 1 × 10 12 < 1.5 × 10 7 Other neon , silicon , sulfur , argon , iron , carbon dioxide , etc. 1. ^ Column density 2. ^ Surface density Mercury has a very tenuous and highly variable atmosphere (surface-bound exosphere ) containing hydrogen , helium , oxygen , sodium , calcium , potassium and water vapor , with a combined pressure level of about 10 −14 bar (1
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Unformatted text preview: nPa ). [2] The exospheric species originate either from the Solar wind or from the planetary crust. Solar light pushes the atmospheric gases away from the Sun, creating a comet-like tail behind the planet. The existence of a Hermian atmosphere had been contentious before 1974, although by that time a consensus had formed that Mercury, like the Moon , lacked any substantial atmosphere. This conclusion was confirmed in 1974 when the Mariner 10 spacecraft discovered only a tenuous exosphere. Later, in 2008, improved measurements were obtained by the MESSENGER spacecraft, which discovered magnesium in the Hermian exosphere....
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Atmosphere of Mercury - nPa ). [2] The exospheric species...

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