About the loss of a primordial atmosphere of super-Earths by planetesimal impacts

Michael Lozovsky, Dina Prialnik, Morris Podolak

Research output: Contribution to journalArticlepeer-review

1 Scopus citations


We consider planets composed of water ice and rock, located far from a central star. In an earlier study, computing the growth of planets by continuous accretion, we found that a large fraction of the ice evaporates upon accretion, creating a water vapor atmosphere. Here, we consider accretion as a discrete series of planetesimal impacts (of the order of 108), at the same time-dependent accretion rate, and investigate the fate of the vapor, as a result of its interaction with the accreting planetesimals. We find that a large fraction of the vapor escapes. The remaining fraction may form an outer layer of ice after the termination of accretion and cooling of the surface. The escaped water mass may significantly alter the ice-to-rock ratio of the planet. We investigate the effect of different choices of parameters such as the ice-to-rock ratio, the planetesimal size distribution, and the impact velocities. We find that the planetesimal size distribution has a negligible effect and explain why. By contrast, the ice-to-rock ratio and impact velocities affect the fraction of retained water masses considerably.

Original languageEnglish
Pages (from-to)L70-L73
JournalMonthly Notices of the Royal Astronomical Society: Letters
Issue number1
StatePublished - 1 May 2023


FundersFunder number
Pazy Fund of the Israel Atomic Energy Commission


    • planets and satellites: composition
    • planets and satellites: formation
    • planets and satellites: fundamental parameters


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