Piia Maria TombergUniversity of Copenhagen, Globe Institute, Anders JohansenUniversity of Copenhagen, Globe Institute
{"title":"Evolution of gas envelopes and outgassed atmospheres of rocky planets formed via pebble accretion","authors":"Piia Maria TombergUniversity of Copenhagen, Globe Institute, Anders JohansenUniversity of Copenhagen, Globe Institute","doi":"arxiv-2409.11005","DOIUrl":null,"url":null,"abstract":"We present here results of numerical simulations of the formation and early\nevolution of rocky planets through pebble accretion, with an with an emphasis\non hydrogen envelope longevity and the composition of the outgassed atmosphere.\nWe model planets with a range in mass from 0.1 to 5 Earth masses that orbit\nbetween 0.7 and 1.7 AU. The composition of the outgassed atmosphere is\ncalculated with the partial pressure of free oxygen fit to geophysical models\nof magma ocean self-oxidation. XUV radiation powered photoevaporation is\nconsidered as the main driver of atmospheric escape. We model planets that\nremain below the pebble isolation mass and hence accrete tenuous envelopes\nonly. We consider slow, medium or fast initial stellar rotation for the\ntemporal evolution of the XUV flux. The loss of the envelope is a key event\nthat allows the magma ocean to crystallise and outgas its bulk volatiles. The\natmospheric composition of the majority of our simulated planets is dominated\nby CO$_2$. Our planets accrete a total of 11.6 Earth oceans of water, the\nmajority of which enters the core. The hydrospheres of planets lighter than the\nEarth reach several times the mass of the Earth's modern oceans, while the\nhydrospheres of planets ranging from 1 to 3.5 Earth masses are comparable to\nthose of our planet. However, planets of 4-5 Earth masses have smaller\nhydrospheres due to trapping of volatiles in their massive mantles. Overall,\nour simulations demonstrate that hydrogen envelopes are easily lost from rocky\nplanets and that this envelope loss triggers the most primordial partitioning\nof volatiles between the solid mantle and the atmosphere.","PeriodicalId":501209,"journal":{"name":"arXiv - PHYS - Earth and Planetary Astrophysics","volume":"48 1","pages":""},"PeriodicalIF":0.0000,"publicationDate":"2024-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"arXiv - PHYS - Earth and Planetary Astrophysics","FirstCategoryId":"1085","ListUrlMain":"https://doi.org/arxiv-2409.11005","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"","JCRName":"","Score":null,"Total":0}
引用次数: 0
Abstract
We present here results of numerical simulations of the formation and early
evolution of rocky planets through pebble accretion, with an with an emphasis
on hydrogen envelope longevity and the composition of the outgassed atmosphere.
We model planets with a range in mass from 0.1 to 5 Earth masses that orbit
between 0.7 and 1.7 AU. The composition of the outgassed atmosphere is
calculated with the partial pressure of free oxygen fit to geophysical models
of magma ocean self-oxidation. XUV radiation powered photoevaporation is
considered as the main driver of atmospheric escape. We model planets that
remain below the pebble isolation mass and hence accrete tenuous envelopes
only. We consider slow, medium or fast initial stellar rotation for the
temporal evolution of the XUV flux. The loss of the envelope is a key event
that allows the magma ocean to crystallise and outgas its bulk volatiles. The
atmospheric composition of the majority of our simulated planets is dominated
by CO$_2$. Our planets accrete a total of 11.6 Earth oceans of water, the
majority of which enters the core. The hydrospheres of planets lighter than the
Earth reach several times the mass of the Earth's modern oceans, while the
hydrospheres of planets ranging from 1 to 3.5 Earth masses are comparable to
those of our planet. However, planets of 4-5 Earth masses have smaller
hydrospheres due to trapping of volatiles in their massive mantles. Overall,
our simulations demonstrate that hydrogen envelopes are easily lost from rocky
planets and that this envelope loss triggers the most primordial partitioning
of volatiles between the solid mantle and the atmosphere.