Results 261 to 270 of about 1,115,032 (293)

Thermal atmospheric escape of close-in exoplanets

Proceedings of the International Astronomical Union, 2020
AbstractIn this work we applied the previously developed self-consistent 1D model of hydrogen-helium atmosphere with suprathermal electrons to close-in hot neptune GJ 436 b. The obtained height profile of density shows the two-scale structure of the planetary atmosphere. The mass-loss rate is found to be about .
Eugenia S. Kalinicheva, Valery I. Shematovich   +1 more
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Dust storm-enhanced gravity wave activity in the Martian thermosphere observed by MAVEN and implications for atmospheric escape

, 2020
Lower atmospheric global dust storms affect the smalland large-scale weather and variability of the whole Martian atmosphere. Analysis of the CO2 density data from the Neutral Gas and Ion Mass Spectrometer instrument (NGIMS) on board NASA’s Mars ...
Erdal Yiğit, A. Medvedev, M. Benna, B. Jakosky   +3 more
semanticscholar   +1 more source

Escape of Planetary Atmospheres

2012
The extreme radiation and plasma environments during the period of the young active Sun/Stars have important implications for the evolution of planetary atmospheres and may be responsible that planets with a low gravity like early Mars most likely could never build up a dense atmosphere during the first few 100 Myr after their origin. On the other hand
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Titan's hydrodynamically escaping atmosphere

Icarus, 2008
Abstract The upper atmosphere of Titan is currently losing mass at a rate ∼ ( 4 – 5 ) × 10 28 amu s −1 , by hydrodynamic escape as a high density, slow outward expansion driven principally by solar UV heating by CH4 absorption. The hydrodynamic mass loss is essentially CH4 and H2 escape.
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Escape and Stand of the Pluto Atmosphere

Communications in Theoretical Physics, 2002
Molar mass mu(min) of the lightest gas, Which will exist "forever" in the atmosphere at the planet surface, can be evaluated by Jeans rule. The mu(min) of Pluto is 17.3 g . mol(-1). It is evident that both N-2 and CO can be major atmospheric composition at the Pluto surface, and will exist "forever".
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An attractive problem on atmospheric escape

Journal of Chemical Education, 1980
A question on escape velocity is representative of the wealth of material that can be exploited from applying the gas laws to atmospheric and meteorological phenomenon.
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Effects of the IMF Direction on Atmospheric Escape From a Mars‐like Planet Under Weak Intrinsic Magnetic Field Conditions

Journal of Geophysical Research - Space Physics, 2019
Direction of the upstream interplanetary magnetic field (IMF) significantly changes the magnetospheric configuration, influencing the atmospheric escape mechanism. This paper investigates effects of IMF on the ion escape mechanism from a Mars‐like planet
S. Sakai, K. Seki, N. Terada, H. Shinagawa, R. Sakata, Takashi Tanaka, Y. Ebihara   +6 more
semanticscholar   +1 more source

Photon escape probabilities in expanding atmospheres

Journal of Astrophysics and Astronomy, 1981
A comparison of mean number of scatterings and escape probabilities has been made in isotropic scattering and dipole scattering by using the angle-averaged partial frequency redistribution functionR I. We have solved the equations of radiative transfer and statistical equilibrium simultaneously in a spherically symmetric expanding ...
A. Peraiah, K. E. Rangarajan, D. Mohan Rao   +2 more
openaire   +1 more source

The escape of helium from the Earth's atmosphere

Reviews of Geophysics, 1963
The rate of influx of helium 4 from the earth's crust into the atmosphere is about 2 × 106 atoms cm−2 sec−1. The average rate of thermal escape averaged over the last solar cycle is 6 × 104 atoms cm−2 sec−1. The present abundance of helium in the atmosphere would accumulate in about two million years. Either some nonthermal mechanism permits at present
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Escape of atmospheric helium by nonthermal processes

Reviews of Geophysics, 1968
Several nonthermal mechanims have been proposed to resolve the discrepancy between the rate at which helium is released from the earth's crust and the average rate of thermal escape of the gas. The various mechanisms are examined critically. Loss of its ions from the polar ionosphere appears to be the most likely mechanism controlling the escape of ...
openaire   +1 more source