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Escape of the martian protoatmosphere and initial water inventory.

Erkaev NV, Lammer H, Elkins-Tanton LT, Stökl A, Odert P, Marcq E, Dorfi EA, Kislyakova KG, Kulikov YN, Leitzinger M, Güdel M - Planet Space Sci (2014)

Bottom Line: If this was not the case, then our results suggest that the timescales for H2O condensation and ocean formation may have been shorter compared to the atmosphere evaporation timescale, so that one can speculate that sporadically periods, where some amount of liquid water may have been present on the planet's surface.However, depending on the amount of the outgassed volatiles, because of impacts and the high XUV-driven atmospheric escape rates, such sporadically wet surface conditions may have also not lasted much longer than [Formula: see text].After the loss of the captured hydrogen envelope and outgassed volatiles during the first 100 Myr period of the young Sun, a warmer and probably wetter period may have evolved by a combination of volcanic outgassing and impact delivered volatiles [Formula: see text] ago, when the solar XUV flux decreased to values that have been [Formula: see text] times that of today's Sun.

View Article: PubMed Central - PubMed

Affiliation: Institute for Computational Modelling, 660041 Krasnoyarsk 36, Russian Academy of Sciences, Russian Federation ; Siberian Federal University, 660041 Krasnoyarsk, Russian Federation.

ABSTRACT

Latest research in planet formation indicates that Mars formed within a few million years (Myr) and remained as a planetary embryo that never grew to a more massive planet. It can also be expected from dynamical models that most of Mars' building blocks consisted of material that formed in orbital locations just beyond the ice line which could have contained [Formula: see text] of H2O. By using these constraints, we estimate the nebula-captured and catastrophically outgassed volatile contents during the solidification of Mars' magma ocean and apply a hydrodynamic upper atmosphere model for the study of the soft X-ray and extreme ultraviolet (XUV) driven thermal escape of the martian protoatmosphere during the early active epoch of the young Sun. The amount of gas that has been captured from the protoplanetary disk into the planetary atmosphere is calculated by solving the hydrostatic structure equations in the protoplanetary nebula. Depending on nebular properties such as the dust grain depletion factor, planetesimal accretion rates and luminosities, hydrogen envelopes with masses [Formula: see text] to [Formula: see text] could have been captured from the nebula around early Mars. Depending on the before mentioned parameters, due to the planets low gravity and a solar XUV flux that was [Formula: see text] times stronger compared to the present value, our results indicate that early Mars would have lost its nebular captured hydrogen envelope after the nebula gas evaporated, during a fast period of [Formula: see text]. After the solidification of early Mars' magma ocean, catastrophically outgassed volatiles with the amount of [Formula: see text] H2O and [Formula: see text] CO2 could have been lost during [Formula: see text], if the impact related energy flux of large planetesimals and small embryos to the planet's surface lasted long enough, that the steam atmosphere could have been prevented from condensing. If this was not the case, then our results suggest that the timescales for H2O condensation and ocean formation may have been shorter compared to the atmosphere evaporation timescale, so that one can speculate that sporadically periods, where some amount of liquid water may have been present on the planet's surface. However, depending on the amount of the outgassed volatiles, because of impacts and the high XUV-driven atmospheric escape rates, such sporadically wet surface conditions may have also not lasted much longer than [Formula: see text]. After the loss of the captured hydrogen envelope and outgassed volatiles during the first 100 Myr period of the young Sun, a warmer and probably wetter period may have evolved by a combination of volcanic outgassing and impact delivered volatiles [Formula: see text] ago, when the solar XUV flux decreased to values that have been [Formula: see text] times that of today's Sun.

No MeSH data available.


Related in: MedlinePlus

Illustration of Mars' origin and protoatmosphere formation and evolution. The dotted lines correspond to the accumulation during the growth and escape of nebula-based hydrogen from proto-Mars. The onset of escape corresponds to the nebula dissipation time around , which is also the expected time period when Mars finished its accretion (Brasser, 2013). The short dashed lines illustrate the catastrophically outgassed volatiles and their expected escape after the planet's magma ocean solidified. Later on when the solar activity decreased a secondary CO2 atmosphere could have build up by volcanic activity (Grott et al., 2011; Lammer et al., 2013a) and the late heavy bombardment may also have delivered volatiles to Mars  ago.
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f0005: Illustration of Mars' origin and protoatmosphere formation and evolution. The dotted lines correspond to the accumulation during the growth and escape of nebula-based hydrogen from proto-Mars. The onset of escape corresponds to the nebula dissipation time around , which is also the expected time period when Mars finished its accretion (Brasser, 2013). The short dashed lines illustrate the catastrophically outgassed volatiles and their expected escape after the planet's magma ocean solidified. Later on when the solar activity decreased a secondary CO2 atmosphere could have build up by volcanic activity (Grott et al., 2011; Lammer et al., 2013a) and the late heavy bombardment may also have delivered volatiles to Mars ago.

Mentions: degassing by volcanic processes during geological epochs.


Escape of the martian protoatmosphere and initial water inventory.

Erkaev NV, Lammer H, Elkins-Tanton LT, Stökl A, Odert P, Marcq E, Dorfi EA, Kislyakova KG, Kulikov YN, Leitzinger M, Güdel M - Planet Space Sci (2014)

Illustration of Mars' origin and protoatmosphere formation and evolution. The dotted lines correspond to the accumulation during the growth and escape of nebula-based hydrogen from proto-Mars. The onset of escape corresponds to the nebula dissipation time around , which is also the expected time period when Mars finished its accretion (Brasser, 2013). The short dashed lines illustrate the catastrophically outgassed volatiles and their expected escape after the planet's magma ocean solidified. Later on when the solar activity decreased a secondary CO2 atmosphere could have build up by volcanic activity (Grott et al., 2011; Lammer et al., 2013a) and the late heavy bombardment may also have delivered volatiles to Mars  ago.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4375622&req=5

f0005: Illustration of Mars' origin and protoatmosphere formation and evolution. The dotted lines correspond to the accumulation during the growth and escape of nebula-based hydrogen from proto-Mars. The onset of escape corresponds to the nebula dissipation time around , which is also the expected time period when Mars finished its accretion (Brasser, 2013). The short dashed lines illustrate the catastrophically outgassed volatiles and their expected escape after the planet's magma ocean solidified. Later on when the solar activity decreased a secondary CO2 atmosphere could have build up by volcanic activity (Grott et al., 2011; Lammer et al., 2013a) and the late heavy bombardment may also have delivered volatiles to Mars ago.
Mentions: degassing by volcanic processes during geological epochs.

Bottom Line: If this was not the case, then our results suggest that the timescales for H2O condensation and ocean formation may have been shorter compared to the atmosphere evaporation timescale, so that one can speculate that sporadically periods, where some amount of liquid water may have been present on the planet's surface.However, depending on the amount of the outgassed volatiles, because of impacts and the high XUV-driven atmospheric escape rates, such sporadically wet surface conditions may have also not lasted much longer than [Formula: see text].After the loss of the captured hydrogen envelope and outgassed volatiles during the first 100 Myr period of the young Sun, a warmer and probably wetter period may have evolved by a combination of volcanic outgassing and impact delivered volatiles [Formula: see text] ago, when the solar XUV flux decreased to values that have been [Formula: see text] times that of today's Sun.

View Article: PubMed Central - PubMed

Affiliation: Institute for Computational Modelling, 660041 Krasnoyarsk 36, Russian Academy of Sciences, Russian Federation ; Siberian Federal University, 660041 Krasnoyarsk, Russian Federation.

ABSTRACT

Latest research in planet formation indicates that Mars formed within a few million years (Myr) and remained as a planetary embryo that never grew to a more massive planet. It can also be expected from dynamical models that most of Mars' building blocks consisted of material that formed in orbital locations just beyond the ice line which could have contained [Formula: see text] of H2O. By using these constraints, we estimate the nebula-captured and catastrophically outgassed volatile contents during the solidification of Mars' magma ocean and apply a hydrodynamic upper atmosphere model for the study of the soft X-ray and extreme ultraviolet (XUV) driven thermal escape of the martian protoatmosphere during the early active epoch of the young Sun. The amount of gas that has been captured from the protoplanetary disk into the planetary atmosphere is calculated by solving the hydrostatic structure equations in the protoplanetary nebula. Depending on nebular properties such as the dust grain depletion factor, planetesimal accretion rates and luminosities, hydrogen envelopes with masses [Formula: see text] to [Formula: see text] could have been captured from the nebula around early Mars. Depending on the before mentioned parameters, due to the planets low gravity and a solar XUV flux that was [Formula: see text] times stronger compared to the present value, our results indicate that early Mars would have lost its nebular captured hydrogen envelope after the nebula gas evaporated, during a fast period of [Formula: see text]. After the solidification of early Mars' magma ocean, catastrophically outgassed volatiles with the amount of [Formula: see text] H2O and [Formula: see text] CO2 could have been lost during [Formula: see text], if the impact related energy flux of large planetesimals and small embryos to the planet's surface lasted long enough, that the steam atmosphere could have been prevented from condensing. If this was not the case, then our results suggest that the timescales for H2O condensation and ocean formation may have been shorter compared to the atmosphere evaporation timescale, so that one can speculate that sporadically periods, where some amount of liquid water may have been present on the planet's surface. However, depending on the amount of the outgassed volatiles, because of impacts and the high XUV-driven atmospheric escape rates, such sporadically wet surface conditions may have also not lasted much longer than [Formula: see text]. After the loss of the captured hydrogen envelope and outgassed volatiles during the first 100 Myr period of the young Sun, a warmer and probably wetter period may have evolved by a combination of volcanic outgassing and impact delivered volatiles [Formula: see text] ago, when the solar XUV flux decreased to values that have been [Formula: see text] times that of today's Sun.

No MeSH data available.


Related in: MedlinePlus