An impact-free mechanism to deliver water to terrestrial planets and exoplanets
arXiv:2412.01409 · doi:10.1051/0004-6361/202451263
Abstract
To date, the most widespread scenario is that the Earth originated without water and was brought to the planet mainly due to impacts by wet asteroids coming from further out in space. However, many uncertainties remain regarding the exact processes that supply water to inner terrestrial planets. This article explores a new mechanism that would allow water to be efficiently transported to planets without impacts. We propose that primordial asteroids were icy and that when the ice sublimated, it formed a gaseous disk that could then reach planets and deliver water. We have developed a new model that follows the sublimation of asteroids and evolves the subsequent gas disk using a viscous diffusion code. We can then quantify the amount of water that can be accreted onto each planet in a self-consistent manner. We find that this new disk-delivery mechanism can explain the water content on Earth as well as on other planets. Our model shows most of the water being delivered between 20 and 30 Myr after the birth of the Sun. Our scenario implies the presence of a gaseous water disk with substantial mass for 100s Myr, which could be one of the key tracers of this mechanism. We show that such a watery disk could be detected in young exo-asteroid belts with ALMA. We propose that viscous water transport is inevitable and more generic than the impact scenario. We also suggest it is a universal process that may also occur in extrasolar systems. The conditions required for this scenario to unfold are indeed expected to be present in most planetary systems: an opaque proto-planetary disk that is initially cold enough for ice to form in the exo-asteroid belt region, followed by a natural outward-moving snow line that allows this initial ice to sublimate after the dissipation of the primordial disk, creating a viscous secondary gas disk and leading to the accretion of water onto the exoplanets.
26 pages, 11 figures, accepted for publication in A&A. Abstract shortened
References in corpus (34)
- The origins and concentrations of water, carbon, nitrogen and noble gases on Earth
- Origin of water in the inner Solar System: Planetesimals scattered inward during Jupiter and Saturn's rapid gas accretion
- Water Delivery and Giant Impacts in the 'Grand Tack' Scenario
- On the Location of the Snow Line in a Protoplanetary Disk
- CESAM: a free code for stellar evolution calculations
- Long-Term Collisional Evolution of Debris Disks
- Water in star-forming regions (WISH): Physics and chemistry from clouds to disks as probed by Herschel spectroscopy
- Formation of a disc gap induced by a planet: Effect of the deviation from Keplerian disc rotation
- A highly settled disk around Oph 163131
- On the Nature of the Dust in the Debris Disk Around HD69830
- Earth shaped by primordial H atmospheres
- Molecular gas in debris disks around young A-type stars
- Outward migration of Jupiter and Saturn in 3:2 or 2:1 resonance in radiative disks: implications for the Grand Tack and Nice models
- Measuring Jupiter's water abundance by Juno: the link between interior and formation models
- Time evolution of snow regions and planet traps in an evolving protoplanetary disk
- Influence of planetary gas accretion on the shape and depth of gaps in protoplanetary discs
- The highly active Anhur-Bes regions in the 67P/Churyumov - Gerasimenko comet: results from OSIRIS/ROSETTA observations
- Survey of planetesimal belts with ALMA: gas detected around the Sun-like star HD 129590
- Planet Shadows in Protoplanetary Disks. I: Temperature Perturbations
- Covariant Residual Entropy
- Recycling of the first atmospheres of embedded planets: Dependence on core mass and optical depth
- Evolution of the Earth's Atmosphere during Late Veneer Accretion
- Primordial or Secondary? Testing models of debris disk gas with ALMA
- What Sets the Radial Locations of Warm Debris Disks?
- Resolved ALMA observations of water in the inner astronomical units of the HL Tau disk
- Volatile exposures on the 67P/Churyumov-Gerasimenko nucleus
- A molecular wind blows out of the Kuiper belt
- Gaia view of primitive inner-belt asteroid families: Searching for the origins of asteroids Bennu and Ryugu
- Migration of pairs of giant planets in low-viscosity discs
- Stellar Parameters for HD 69830, a Nearby Star with Three Neptune Mass Planets and an Asteroid Belt
- Building protoplanetary disks from the molecular cloud: redefining the disk timeline
- Albedo variegation on Comet 67P/Churyumov-Gerasimenko
- Stellar winds can affect gas dynamics in debris disks and create observable belt winds
- Crash Chronicles: relative contribution from comets and carbonaceous asteroids to Earth's volatile budget in the context of an Early Instability