On the Origin and Thermal Stability of Arrokoths and Plutos Ices
arXiv:2009.02277 · doi:10.1016/j.icarus.2020.114072
Abstract
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.
34 Pages, 5 Figures, 2 SOM Tables
References in corpus (16)
- The Active Centaurs
- Initial results from the New Horizons exploration of 2014 MU69, a small Kuiper Belt Object
- Ralph: A Visible/Infrared Imager for the New Horizons Pluto/Kuiper Belt Mission
- Densities of Solar System Objects from their Rotational Lightcurves
- The solar nebula origin of (486958) Arrokoth, a primordial contact binary in the Kuiper belt
- The Geology and Geophysics of Kuiper Belt Object (486958) Arrokoth
- Color, Composition, and Thermal Environment of Kuiper Belt Object (486958) Arrokoth
- Solution to the debris disc mass problem: planetesimals are born small?
- An unbiased ALMA spectral survey of the LkCa 15 and MWC 480 protoplanetary disks
- Low 60Fe abundance in Semarkona and Sahara 99555
- Dynamic Sublimation Pressure and the Catastrophic Breakup of Comet ISON
- Jupiter's formation in the vicinity of the amorphous ice snowline
- The CH4 cycles on Pluto over seasonal and astronomical timescales
- How to link the relative abundances of gas species in coma of comets to their initial chemical composition ?
- Infrared Spectroscopy of HR 4796A's Bright Outer Cometary Ring + Tenuous Inner Hot Dust Cloud
- Hubble Space Telescope Search for Activity in High Perihelion Objects
Cited by in corpus (20)
- A SUBLIME 3D Model for Cometary Coma Emission: the Hypervolatile-Rich Comet C/2016 R2 (PanSTARRS)
- Irradiation dose affects the composition of organic refractory materials in space: Results from laboratory analogues
- Sublimation of ices during the early evolution of Kuiper belt objects
- Are there any pristine comets? Constraints from pebble structure
- Modification of icy planetesimals by early thermal evolution and collisions: Constraints for formation time and initial size of comets and small KBOs
- A molecular wind blows out of the Kuiper belt
- Thermal Alteration and Differential Sublimation Can Create Phaethons "Rock Comet" Activity and Blue Color
- Perihelion Asymmetry in the Water Production Rate of the Interstellar Object 3I/ATLAS
- Water ice in the debris disk around HD 181327
- The Volatile Inventory of 3I/ATLAS as seen with JWST/MIRI
- RW Aur A : SpeX Spectral Evidence for Differentiated Planetesimal Formation, Migration and Destruction in an 3 Myr Old Excited CTTS System
- Stellar winds can affect gas dynamics in debris disks and create observable belt winds
- Collisional heating of icy planetesimals. I. Catastrophic collisions
- Volatile-rich comets ejected early on during Solar System formation
- A link between the size and composition of comets
- Nitrogen Loss from Pluto's Birth to the Present Day via Atmospheric Escape, Photochemical Destruction, and Impact Erosion
- Evidence of Possible Spectral Variability in the Patroclus-Menoetius Binary System
- Considering contact forces during the formation of planetesimals by gravitational collapse: mutual orbits, spin states, and shapes
- JWST/NIRSpec Observations of Salacia-Actaea and Máni: Exploring Population-level Trends among Water-ice-rich Kuiper Belt Objects
- Direct contact binary planetesimal formation from gravitational collapse