Abstract-In the primordial solar system, the most plausible sources of the water accreted by the Earth were in the outer asteroid belt, in the giant planet regions, and in the Kuiper Belt. We investigate the implications on the origin of Earth's water of dynamical models of primordial evolution of solar system bodies and check them with respect to chemical constraints. We find that it is plausible that the Earth accreted water all along its formation, from the early phases when the solar nebula was still present to the late stages of gas-free sweepup of scattered planetesimals. Asteroids and the comets from the Jupiter-Saturn region were the first water deliverers, when the Earth was less than half its present mass. The bulk of the water presently on Earth was carried by a few planetary embryos, originally formed in the outer asteroid belt and accreted by the Earth at the final stage of its formation. Finally, a late veneer, accounting for at most 10% of the present water mass, occurred due to comets from the Uranus-Neptune region and from the Kuiper Belt. The net result of accretion from these several reservoirs is that the water on Earth had essentially the D/H ratio typical of the water condensed in the outer asteroid belt. This is in agreement with the observation that the D/H ratio in the oceans is very close to the mean value of the D/H ratio of the water inclusions in carbonaceous chondrites.
7We report the orbital distribution of the trans-neptunian objects (TNOs) discovered during the Canada-France Ecliptic Plane Survey (CFEPS), whose discovery phase ran from early 2003 until early 2007. The follow-up observations started just after the first discoveries and extended until late 2009. We obtained characterized observations of 321 sq.deg. of sky to depths in the range g ∼23.5 -24.4 AB mag. We provide a database of 169 TNOs with high-precision dynamical classification and known discovery efficiency. Using this database, we find that the classical belt is a complex region with sub-structures that go beyond the usual splitting of inner (interior to 3:2 mean-motion resonance [MMR]), main (between 3:2 and 2:1 MMR), and outer (exterior to 2:1 MMR). The main classical belt (a=40-47 AU) needs to be modeled with 1 Based on observations obtained with MegaPrime/MegaCam, a joint project of CFHT and CEA/DAPNIA, at the Canada-France-Hawaii Telescope (CFHT) which is operated by the at least three components: the 'hot' component with a wide inclination distribution and two 'cold' components (stirred and kernel) with much narrower inclination distributions. The hot component must have a significantly shallower absolute magnitude (H g ) distribution than the other two components. With 95% confidence, there are 8000 +1800 −1600 objects in the main belt with H g ≤ 8.0, of which 50% are from the hot component, 40% from the stirred component and 10% from the kernel; the hot component's fraction drops rapidly with increasing H g . Because of this, the apparent population fractions depend on the depth and ecliptic latitude of a transneptunian survey. The stirred and kernel components are limited to only a portion of the main belt, while we find that the hot component is consistent with a smooth extension throughout the inner, main and outer regions of the classical belt; in fact, the inner and outer belts are consistent with containing only hot-component objects. The H g ≤ 8.0 TNO population estimates are 400 for the inner belt and 10,000 for the outer belt to within a factor of two (95% confidence). We show how the CFEPS Survey Simulator can be used to compare a cosmogonic model for the the orbital element distribution to the real Kuiper belt. Subject headings: Kuiper Belt, surveys; PACS 96.30.Xa 8 9 42 non-resonant, non-scattering part of the belt beyond the 2:1 MMR with Neptune. Section 6 gives an order 43 of magntitude estimate of the scattering disk's population. Section 7 demonstrates the use of our Survey 44 -4 -Simulator to compare the results of a cosmogonic model to the CFEPS detections. Finally in Section 8, we 45 present our conclusions and put our findings in perspective. 46 2. Observations and Initial reductions 47 The discovery component of the CFEPS project imaged ∼320 square degrees of sky, almost all of 48 which was within a few degrees of the ecliptic plane. Discovery observations occurred in blocks of ≈ 16 49 fields acquired using the Canada-France-Hawaii Telescope (CFHT) MegaPrime camera which delivered ...
The trans-Neptunian objects (TNOs) trapped in mean-motion resonances with Neptune were likely emplaced there during planet migration late in the giant-planet formation process. We perform detailed modeling of the resonant objects detected in the Canada-France Ecliptic Plane Survey (CFEPS) in order to provide population estimates and, for some resonances, constrain the complex internal orbital element distribution. Detection biases play a critical role because phase relationships with Neptune make object discovery more likely at certain longitudes. This paper discusses the 3:2, 5:2, 2:1, 3:1, 5:1, 4:3, 5:3, 7:3, 5:4, and 7:4 mean-motion resonances, all of which had CFEPS detections, along with our upper limit on 1:1 Neptune Trojans (which is consistent with their small population estimated elsewhere). For the Plutinos (TNOs in the 3:2 resonance) we refine the orbital element distribution given in Kavelaars et al. (2009) and show that steep H-magnitude distributions (N (H ) ∝ 10 αH , with α = 0.8-0.9) are favored in the range H g = 8-9, and confirm that this resonance does not share the inclination distribution of the classical Kuiper Belt. We give the first population estimate for the 5:2 resonance and find that, to within the uncertainties, the population is equal to that of the 3:2 ( 13,000 TNOs with H g < 9.16), whereas the 2:1 population is smaller by a factor of 3-4 compared to the other two resonances. We also measure significant populations inhabiting the 4:3, 5:3, 7:3, 5:4, 7:4, 3:1, and 5:1 resonances, with H g < 9.16 (D > 100 km) populations in the thousands. We compare our intrinsic population and orbital element distributions with several published models of resonant-TNO production; the most striking discrepancy is that resonances beyond the 2:1 are in reality more heavily populated than in published models.
The size distribution in the Kuiper Belt records physical processes operating during the formation and subsequent evolution of the solar system. This paper reports a study of the apparent magnitude distribution of faint objects in the Kuiper Belt, obtained via deep imaging on the Canada-France-Hawaii Telescope and the ESO Very Large Telescope UT1. We Ðnd that the entire range of observed objects (magnitudes is well represented by an unbroken power law, with the number of objects per m R D 20È27) square degree brighter than magnitude R being of the form with a \ 0.69 andThis luminosity functionÏs slope implies a steep size distribution in the observed range, which R 0 \ 23.5. should "" roll over ÏÏ to a shallower "" collisional ÏÏ slope once observations extend to even fainter magnitudes and thus sample bodies whose collisional ages become less than the age of the solar system. Our observations indicate the roll over is for diameters of less than 50 km, in agreement with collisional models. Modeling our survey gives a belt mass between 30 and 50 AU of order 0.1 relatively insen-M^, sitive to the roll over diameter as long as the latter is km. We report the discovery of several objects Z1 outside of 48 AU and discuss the evidence for a sharp outer edge to the trans-Neptunian distribution.
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