Abstract The loss and gain of volatile elements during planet formation is key for setting their subsequent climate, geodynamics, and habitability. Two broad regimes of volatile element transport in and out of planetary building blocks have been identified: that occurring when the nebula is still present, and that occurring after it has dissipated. Evidence for volatile element loss in planetary bodies after the dissipation of the solar nebula is found in the high Mn to Na abundance ratio of Mars, the Moon, and many of the solar system's minor bodies. This volatile loss is expected to occur when the bodies are heated by planetary collisions and short-lived radionuclides, and enter a global magma ocean stage early in their history. The bulk composition of exo-planetary bodies can be determined by observing white dwarfs which have accreted planetary material. The abundances of Na, Mn, and Mg have been measured for the accreting material in four polluted white dwarf systems. Whilst the Mn/Na abundances of three white dwarf systems are consistent with the fractionations expected during nebula condensation, the high Mn/Na abundance ratio of GD362 means that it is not ( > 3 σ ). We find that heating of the planetary system orbiting GD362 during the star's giant branch evolution is insufficient to produce such a high Mn/Na. We, therefore, propose that volatile loss occurred in a manner analogous to that of the solar system bodies, either due to impacts shortly after their formation or from heating by short-lived radionuclides. We present potential evidence for a magma ocean stage on the exo-planetary body which currently pollutes the atmosphere of GD362.

中文翻译：

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系外行星体中星云后挥发的证据

摘要 行星形成过程中挥发性元素的损失和增加是决定其后续气候、地球动力学和宜居性的关键。已经确定了两种广泛的挥发性元素运输进出行星构件的机制：星云仍然存在时发生的，以及星云消散后发生的。在太阳星云消散后行星体中挥发性元素损失的证据是在火星、月球和许多太阳系小天体的高锰钠丰度比中发现的。当这些物体被行星碰撞和短寿命放射性核素加热并在其历史早期进入全球岩浆海洋阶段时，预计会发生这种不稳定的损失。系外行星体的整体组成可以通过观察具有吸积行星物质的白矮星来确定。已经测量了四个受污染的白矮星系统中吸积物质的 Na、Mn 和 Mg 的丰度。虽然三个白矮星系统的 Mn/Na 丰度与星云凝聚期间预期的分馏一致，但 GD362 的高 Mn/Na 丰度比意味着它不是 (> 3 σ )。我们发现，在恒星巨大分支演化过程中，围绕 GD362 运行的行星系统的加热不足以产生如此高的 Mn/Na。因此，我们提出挥发性损失的发生方式类似于太阳系天体的损失，要么是由于它们形成后不久的撞击，要么是由于短寿命放射性核素的加热。