Planetary Magnetic Dynamo Effect on Atmospheric Protection of Early Earth and Mars

Déhant, V.; Lämmer, H.; Kulikov, Yu. N.; Grießmeier, J.-M.; Breuer, D.; Verhoeven, O.; Karatekin, Özgür; Hoolst, Tim Van; Korablev, Oleg; Lognonné, Philippe

doi:10.1007/s11214-007-9163-9

Cited by 61 publications

(33 citation statements)

References 125 publications

(150 reference statements)

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…While these latter values result from the scaling laws suggested by Grießmeier et al (2005) and Dehant et al (2007) when a faster initial rotation period ($13 h) of the early Earth is considered (MacDonald, 1964), the weaker moment given by Eq.…”

Section: Magnetospheric Protectionmentioning

confidence: 93%

Aeronomical evidence for higher CO2 levels during Earth’s Hadean epoch

Lichtenegger

Lämmer

Grießmeier

et al. 2010

Icarus

Self Cite

122

View full text Add to dashboard Cite

Section: Magnetospheric Protectionmentioning

confidence: 93%

Aeronomical evidence for higher CO2 levels during Earth’s Hadean epoch

Lichtenegger

Lämmer

Grießmeier

et al. 2010

Icarus

Self Cite

122

View full text Add to dashboard Cite

“…Volcanism and magnetic field generation may be important for habitability. Magnetic fields may influence habitability by protecting the planetary atmosphere against erosion by stellar winds [80]. Volcanism adds greenhouse gases to the atmosphere that may be essential for preventing or ending completely ice-covered snowball states.…”

Section: −2β Pmentioning

confidence: 99%

Melting in super-earths

Stixrude

2014

Phil. Trans. R. Soc. A.

104

View full text Add to dashboard Cite

We examine the possible extent of melting in rockiron super-earths, focusing on those in the habitable zone. We consider the energetics of accretion and core formation, the timescale of cooling and its dependence on viscosity and partial melting, thermal regulation via the temperature dependence of viscosity, and the melting curves of rock and iron components at the ultra-high pressures characteristic of superearths. We find that the efficiency of kinetic energy deposition during accretion increases with planetary mass; considering the likely role of giant impacts and core formation, we find that super-earths probably complete their accretionary phase in an entirely molten state. Considerations of thermal regulation lead us to propose model temperature profiles of super-earths that are controlled by silicate melting. We estimate melting curves of iron and rock components up to the extreme pressures characteristic of superearth interiors based on existing experimental and ab initio results and scaling laws. We construct superearth thermal models by solving the equations of mass conservation and hydrostatic equilibrium, together with equations of state of rock and iron components. We set the potential temperature at the core-mantle boundary and at the surface to the local silicate melting temperature. We find that ancient (∼4 Gyr) super-earths may be partially molten at the top and bottom of their mantles, and that mantle convection is sufficiently vigorous to sustain dynamo action over the whole range of super-earth masses.

show abstract

“…Planetary magnetic dynamo theory predicts that the strength of a magnetic moment depends on the planetary rotation rate, the core radius and input energy (either thermal, chemical or gravitational) to drive vigorous internal convection inside the core (e.g., Busse 1976;Stevenson et al 1983;Schubert and Spohn 1990;Dehant et al 2007, this issue). The available data obtained by MGS on an early martian magnetic field are mainly restricted to measurements related to the presence of significant local, small-scale, crustal remnant magnetization (Acuña et al 1998Connerney et al 1999).…”

Section: Magnetic Field Protection Of the Early Martian Atmospherementioning

confidence: 99%

A Comparative Study of the Influence of the Active Young Sun on the Early Atmospheres of Earth, Venus, and Mars

et al. 2007

View full text Add to dashboard Cite

Because the solar radiation and particle environment plays a major role in all atmospheric processes such as ionization, dissociation, heating of the upper atmospheres, and thermal and non-thermal atmospheric loss processes, the long-time evolution of planetary atmospheres and their water inventories can only be understood within the context of the evolving Sun. We compare the effect of solar induced X-ray and EUV (XUV) heating on the upper atmospheres of Earth, Venus and Mars since the time when the Sun arrived at the Zero-Age-Main-Sequence (ZAMS) about 4.6 Gyr ago. We apply a diffusive-gravitational equilibrium and thermal balance model for studying heating of the early thermospheres by photodissociation and ionization processes, due to exothermic chemical reactions and cooling by IR-radiating molecules like CO 2 , NO, OH, etc. Our model simulations result in extended thermospheres for early Earth, Venus and Mars. The exospheric temperatures obtained for all the three planets during this time period lead to diffusion-limited hydrodynamic escape of atomic hydrogen and high Jeans' escape rates for heavier species like H 2 , He, C, N, O, etc. The duration of this blow-off phase for atomic hydrogen depends essentially on the mixing ratios of CO 2 , N 2 and H 2 O in the atmospheres and could last from ∼100 to several hundred million years. Furthermore, we study the efficiency of various non-thermal atmospheric loss processes on Venus and Mars and investigate the possible protecting effect of the early martian magnetosphere against solar wind induced ion pick up Yu.N. Kulikov et al. erosion. We find that the early martian magnetic field could decrease the ion-related nonthermal escape rates by a great amount. It is possible that non-magnetized early Mars could have lost its whole atmosphere due to the combined effect of its extended upper atmosphere and a dense solar wind plasma flow of the young Sun during about 200 Myr after the Sun arrived at the ZAMS. Depending on the solar wind parameters, our model simulations for early Venus show that ion pick up by strong solar wind from a non-magnetized planet could erode up to an equivalent amount of ∼250 bar of O + ions during the first several hundred million years. This accumulated loss corresponds to an equivalent mass of ∼1 terrestrial ocean (TO (1 TO ∼1.39 × 10 24 g or expressed as partial pressure, about 265 bar, which corresponds to ∼2900 m average depth)). Finally, we discuss and compare our findings with the results of preceding studies.

show abstract

Planetary Magnetic Dynamo Effect on Atmospheric Protection of Early Earth and Mars

Cited by 61 publications

References 125 publications

Aeronomical evidence for higher CO2 levels during Earth’s Hadean epoch

Aeronomical evidence for higher CO2 levels during Earth’s Hadean epoch

Melting in super-earths

A Comparative Study of the Influence of the Active Young Sun on the Early Atmospheres of Earth, Venus, and Mars

Contact Info

Product

Resources

About