Impact induced erosion of hot and dense atmospheres

Шувалов, В. В.; Kührt, Ekkehard; Niem, D. de; Wünnemann, K.

doi:10.1016/j.pss.2013.08.018

Cited by 29 publications

(35 citation statements)

References 14 publications

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“…Equation 1 implies that for a Venus-like atmosphere, a 1 km-diameter asteroid or a 2 km-diameter comet are crater-forming. For the atmosphere studied by Shuvalov et al (2014) (a 200 bar atmosphere with a scale height of 40 km), a 8 km-diameter asteroid or a 14 km-diameter comet are crater-forming. In the following sections, we will consider impactors with a diameter of 20 km that should thus be crater-forming even for thick atmospheres.…”

Section: Direct Detection Of Biological Mattermentioning

confidence: 99%

Searching for Biosignatures in Exoplanetary Impact Ejecta

et al. 2017

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With the number of confirmed rocky exoplanets increasing steadily, their characterization and the search for exoplanetary biospheres are becoming increasingly urgent issues in astrobiology. To date, most efforts have concentrated on the study of exoplanetary atmospheres. Instead, we aim to investigate the possibility of characterizing an exoplanet (in terms of habitability, geology, presence of life, etc.) by studying material ejected from the surface during an impact event. For a number of impact scenarios, we estimate the escaping mass and assess its subsequent collisional evolution in a circumstellar orbit, assuming a Sun-like host star. We calculate the fractional luminosity of the dust as a function of time after the impact event and study its detectability with current and future instrumentation. We consider the possibility to constrain the dust composition, giving information on the geology or the presence of a biosphere. As examples, we investigate whether calcite, silica, or ejected microorganisms could be detected. For a 20 km diameter impactor, we find that the dust mass escaping the exoplanet is roughly comparable to the zodiacal dust, depending on the exoplanet's size. The collisional evolution is best modeled by considering two independent dust populations, a spalled population consisting of nonmelted ejecta evolving on timescales of millions of years, and dust recondensed from melt or vapor evolving on much shorter timescales. While the presence of dust can potentially be inferred with current telescopes, studying its composition requires advanced instrumentation not yet available. The direct detection of biological matter turns out to be extremely challenging. Despite considerable difficulties (small dust masses, noise such as exozodiacal dust, etc.), studying dusty material ejected from an exoplanetary surface might become an interesting complement to atmospheric studies in the future. Key Words: Biosignatures-Exoplanets-Impacts-Interplanetary dust-Remote sensing. Astrobiology 17, 721-746.

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Section: Direct Detection Of Biological Mattermentioning

confidence: 99%

Searching for Biosignatures in Exoplanetary Impact Ejecta

et al. 2017

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“…This is particularly relevant for massive atmospheres, like that of Venus, for which this can be relevant for the 10s of km size range of planetesimals that had been predicted to have most effect on the planet's atmosphere. Simulations in this regime were performed in Shuvalov et al (2014), which also provided a prescription to implement this in a manner similar to that presented in §3.2 (see their eqs 7-11). However, since these simulations were only performed for an Earth-like planet, their equations 9 and 10 were not generalised to the range of planet masses being considered here.…”

Section: Massive Atmospheresmentioning

confidence: 99%

Susceptibility of planetary atmospheres to mass loss and growth by planetesimal impacts: the impact shoreline

Wyatt

Kral

Sinclair

2019

Monthly Notices of the Royal Astronomical Society

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This paper considers how planetesimal impacts affect planetary atmospheres. Atmosphere evolution depends on the ratio of gain from volatiles to loss from atmosphere stripping f v ; for constant bombardment, atmospheres with f v < 1 are destroyed in finite time, but grow linearly with time for f v > 1. An impact outcome prescription is used to characterise how f v depends on planetesimal impact velocities, size distribution and composition. Planets that are low mass and/or close to the star have atmospheres that deplete in impacts, while high mass and/or distant planets grow secondary atmospheres. Dividing these outcomes is an f v = 1 impact shoreline analogous to Zahnle & Catling's cosmic shoreline. The impact shoreline's location depends on assumed impacting planetesimal properties, so conclusions for the atmospheric evolution of a planet like Earth with f v ≈ 1 are only as strong as those assumptions. Application to the exoplanet population shows the gap in the planet radius distribution at ∼ 1.5R ⊕ is coincident with the impact shoreline, which has a similar dependence on orbital period and stellar mass to the observed gap. Given sufficient bombardment, planets below the gap would be expected to lose their atmospheres, while those above could have atmospheres enhanced in volatiles. The level of atmosphere alteration depends on the total bombardment a planet experiences, and so on the system's (usually unknown) other planets and planetesimals, though massive distant planets would have low accretion efficiency. Habitable zone planets around lower luminosity stars are more susceptible to atmosphere stripping, disfavouring M stars as hosts of life-bearing planets if Earth-like bombardment is conducive to the development of life.

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“…Precise modeling is, however, difficult to constrain for those sizes and numerical simulations usually focus on the consequences for the solid planet. Erosion of the atmosphere by a few large impacts (above 200 km radius) appears limited, unless airburst processes are considered, especially in a dense atmosphere (Shuvalov, 2009;Shuvalov et al, 2014). Swarms of smaller (1km<R<100km) more mass-effective impactors seem required for this effect to be significant.…”

Section: Impactsmentioning

confidence: 99%

Geoscience for Understanding Habitability in the Solar System and Beyond

et al. 2019

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This paper reviews habitability conditions for a terrestrial planet from the point of view of geosciences. It addresses how interactions between the interior of a planet or a moon and its atmosphere and surface (including hydrosphere and biosphere) can affect habitability of the celestial body. It does not consider in detail the role of the central star but focusses more on surface conditions capable of sustaining life. We deal with fundamental issues of planetary habitability, i.e. the environmental conditions capable of sustaining life, and the above-mentioned interactions can affect the habitability of the celestial body.We address some hotly debated questions including:-How do core and mantle affect the evolution and habitability of planets? -What are the consequences of mantle overturn on the evolution of the interior and atmosphere? -What is the role of the global carbon and water cycles? -What influence do comet and asteroid impacts exert on the evolution of the planet? -How does life interact with the evolution of the Earth's geosphere and atmosphere?-How can knowledge of the solar system geophysics and habitability be applied to exoplanets?In addition, we address the identification of preserved life tracers in the context of the interaction of life with planetary evolution.

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Impact induced erosion of hot and dense atmospheres

Cited by 29 publications

References 14 publications

Searching for Biosignatures in Exoplanetary Impact Ejecta

Searching for Biosignatures in Exoplanetary Impact Ejecta

Susceptibility of planetary atmospheres to mass loss and growth by planetesimal impacts: the impact shoreline

Geoscience for Understanding Habitability in the Solar System and Beyond

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