论文标题
关于arrokoths和plutos Ice的起源和热稳定性
On the Origin and Thermal Stability of Arrokoths and Plutos Ices
论文作者
论文摘要
我们以热力学的地质经验方式讨论稳定多数冰的长期性质，该稳定的多数冰是在Kuiper带对象2014 MU69中存在于EKB中的4.6 Gyr住所作为冷古典物体之后。考虑到在彗星，半人马和KBO上通常在Myr到Gyr的Mu69的阳光阳光表面温度下，在彗星，半人马和KBO上常见的ICE套件的稳定性与升华，我们只发现3个真正折磨的常见冰：HCN，CH3OH和H2O（以增强的稳定性）。 NH3和H2CO ICES的稳定性略有稳定，可以通过EKB的任何正温度偏移来清除，因为附近的超新星和通过O/B星星每1E8-1E9年产生每1e8-1e9年。迄今为止，NH团队报告了在MU69S表面上存在丰富的CH3OH和H2O的证据（Lisse等，2017； Grundy等，2020）。 NH3已被搜索，但找不到。我们预测未来的吸收特征检测将是由于HCN或基于Poly-H2CO的物种引起的。考虑MU69形成期间EKB地区存在的条件，使我们推断出它在光学较厚的中间平面中“在黑暗中”形成，无法看到Nascent，可变性，高度发光的年轻恒星对象ttauri Sun，并在H2O ICE同阶段还漫游了H2o Ice spord concern cooct cooct con。最后，当我们将冰热稳定性分析应用于与MU69相关的身体/种群时，我们发现甲醇冰在外太阳系中可能无处不在。如果冥王星不是一个完全分化的身体，那么它必须从原始星际磁盘源中获得过度挥发性的冰，这是太阳系的前几米尔的存在。在类似的时间范围内，将那个高副本，高度原始的彗星C/2016 R2放在Oort云轨道上。
We discuss in a thermodynamic, geologically empirical way the long-term nature of the stable majority ices that could be present in Kuiper Belt Object 2014 MU69 after its 4.6 Gyr residence in the EKB as a cold classical object. Considering the stability versus sublimation into vacuum for the suite of ices commonly found on comets, Centaurs, and KBOs at the average ~40K sunlit surface temperature of MU69 over Myr to Gyr, we find only 3 common ices that are truly refractory: HCN, CH3OH, and H2O (in order of increasing stability). NH3 and H2CO ices are marginally stable and may be removed by any positive temperature excursions in the EKB, as produced every 1e8 - 1e9 yrs by nearby supernovae and passing O/B stars. To date the NH team has reported the presence of abundant CH3OH and evidence for H2O on MU69s surface (Lisse et al. 2017, Grundy et al. 2020). NH3 has been searched for, but not found. We predict that future absorption feature detections will be due to an HCN or poly-H2CO based species. Consideration of the conditions present in the EKB region during the formation era of MU69 lead us to infer that it formed "in the dark", in an optically thick mid-plane, unable to see the nascent, variable, highly luminous Young Stellar Object-TTauri Sun, and that KBOs contain HCN and CH3OH ice phases in addition to the H2O ice phases found in their Short Period comet descendants. Finally, when we apply our ice thermal stability analysis to bodies/populations related to MU69, we find that methanol ice may be ubiquitous in the outer solar system; that if Pluto is not a fully differentiated body, then it must have gained its hypervolatile ices from proto-planetary disk sources in the first few Myr of the solar systems existence; and that hypervolatile rich, highly primordial comet C/2016 R2 was placed onto an Oort Cloud orbit on a similar timescale.
