439 research outputs found
OSSOS III - Resonant Trans-Neptunian Populations: Constraints from the first quarter of the Outer Solar System Origins Survey
The first two observational sky "blocks" of the Outer Solar System Origins
Survey (OSSOS) have significantly increased the number of well-characterized
observed trans-Neptunian objects (TNOs) in Neptune's mean motion resonances. We
describe the 31 securely resonant TNOs detected by OSSOS so far, and we use
them to independently verify the resonant population models from the
Canada-France Ecliptic Plane Survey (CFEPS; Gladman et al. 2012), with which we
find broad agreement. We confirm that the 5:2 resonance is more populated than
models of the outer Solar System's dynamical history predict; our minimum
population estimate shows that the high eccentricity (e>0.35) portion of the
resonance is at least as populous as the 2:1 and possibly as populated as the
3:2 resonance. One OSSOS block was well-suited to detecting objects trapped at
low libration amplitudes in Neptune's 3:2 resonance, a population of interest
in testing the origins of resonant TNOs. We detected three 3:2 objects with
libration amplitudes below the cutoff modeled by CFEPS; OSSOS thus offers new
constraints on this distribution. The OSSOS detections confirm that the 2:1
resonance has a dynamically colder inclination distribution than either the 3:2
or 5:2 resonances. Using the combined OSSOS and CFEPS 2:1 detections, we
constrain the fraction of 2:1 objects in the symmetric mode of libration to be
0.2-0.85; we also constrain the fraction of leading vs. trailing asymmetric
librators, which has been theoretically predicted to vary depending on
Neptune's migration history, to be 0.05-0.8. Future OSSOS blocks will improve
these constraints.Comment: Accepted for publication in A
Col-OSSOS: The Colours of the Outer Solar System Origins Survey
The Colours of the Outer Solar System Origins Survey (Col-OSSOS) is acquiring
near-simultaneous , , and photometry of unprecedented precision with
the Gemini North Telescope, targeting nearly a hundred trans-Neptunian objects
(TNOs) brighter than mag discovered in the Outer Solar System
Origins Survey. Combining the optical and near-infrared photometry with the
well-characterized detection efficiency of the Col-OSSOS target sample will
provide the first flux-limited compositional dynamical map of the outer Solar
System. In this paper, we describe our observing strategy and detail the data
reduction processes we employ, including techniques to mitigate the impact of
rotational variability. We present optical and near-infrared colors for 35
TNOs. We find two taxonomic groups for the dynamically excited TNOs, the
neutral and red classes, which divide at . Based on simple
albedo and orbital distribution assumptions, we find that the neutral class
outnumbers the red class, with a ratio of 4:1 and potentially as high as 11:1.
Including in our analysis constraints from the cold classical objects, which
are known to exhibit unique albedos and colors, we find that within our
measurement uncertainty, our observations are consistent with the primordial
Solar System protoplanetesimal disk being neutral-class-dominated, with two
major compositional divisions in color space.Comment: Accepted to ApJS; on-line supplemental files will be available with
the AJS published version of the pape
OSSOS XXV: Large Populations and Scattering-Sticking in the Distant Transneptunian Resonances
There have been 77 TNOs discovered to be librating in the distant
transneptunian resonances (beyond the 2:1 resonance, at semimajor axes greater
than 47.7~AU) in four well-characterized surveys: the Outer Solar System
Origins Survey (OSSOS) and three similar prior surveys. Here we use the OSSOS
Survey Simulator to measure their intrinsic orbital distributions using an
empirical parameterized model. Because many of the resonances had only one or
very few detections, : resonant objects were grouped by in order to
have a better basis for comparison between models and reality. We also use the
Survey Simulator to constrain their absolute populations, finding that they are
much larger than predicted by any published Neptune migration model to date; we
also find population ratios that are inconsistent with published models,
presenting a challenge for future Kuiper Belt emplacement models. The estimated
population ratios between these resonances are largely consistent with
scattering-sticking predictions, though further discoveries of resonant TNOs
with high-precision orbits will be needed to determine whether
scattering-sticking can explain the entire distant resonant population or not.Comment: Accepted for publication in Planetary Sciences Journal (PSJ
OSSOS: XIII. Fossilized Resonant Dropouts Tentatively Confirm Neptune's Migration was Grainy and Slow
The migration of Neptune's resonances through the proto-Kuiper belt has been
imprinted in the distribution of small bodies in the outer Solar System. Here
we analyze five published Neptune migration models in detail, focusing on the
high pericenter distance (high-q) trans-Neptunian Objects (TNOs) near Neptune's
5:2 and 3:1 mean-motion resonances, because they have large resonant
populations, are outside the main classical belt, and are relatively isolated
from other strong resonances. We compare the observationally biased output from
these dynamical models with the detected TNOs from the Outer Solar System
Origins Survey, via its Survey Simulator. All of the four new OSSOS detections
of high-q non-resonant TNOs are on the Sunward side of the 5:2 and 3:1
resonances. We show that even after accounting for observation biases, this
asymmetric distribution cannot be drawn from a uniform distribution of TNOs at
2sigma confidence. As shown by previous work, our analysis here tentatively
confirms that the dynamical model that uses grainy slow Neptune migration
provides the best match to the real high-q TNO orbital data. However, due to
extreme observational biases, we have very few high-q TNO discoveries with
which to statistically constrain the models. Thus, this analysis provides a
framework for future comparison between the output from detailed, dynamically
classified Neptune migration simulations and the TNO discoveries from future
well-characterized surveys. We show that a deeper survey (to a limiting
r-magnitude of 26.0) with a similar survey area to OSSOS could statistically
distinguish between these five Neptune migration models.Comment: Accepted for publication in the Astronomical Journa
A dearth of small members in the Haumea family revealed by OSSOS
An extensive survey to search for members of the only known Kuiper belt family, named after the parent body Haumea, found no family members fainter than absolute magnitude H-r = 7.9, significantly brighter than the detection limit (H-r = 9.5). This lack of small members is inconsistent with a catastrophic disruption as the origin of the Haumea family. While collisional families are common in the asteroid belt, only one is known in the Kuiper belt, linked to the dwarf planet Haumea. The characterization of Haumea's family helps to constrain its origin and, more generally, the collisional history of the Kuiper belt. However, the size distribution of the Haumea family is difficult to constrain from the known sample, which is affected by discovery biases. Here, we use the Outer Solar System Origins Survey (OSSOS) Ensemble to look for Haumea family members. In this OSSOS XVI study we report the detection of three candidates with small ejection velocities relative to the family formation centre. The largest discovery, 2013 UQ(15), is conclusively a Haumea family member, with a low ejection velocity and neutral surface colours. Although the OSSOS Ensemble is sensitive to Haumea family members to a limiting absolute magnitude (H-r) of 9.5 (inferred diameter of ~90 km), the smallest candidate is significantly larger, H-r = 7.9. The Haumea family members larger than similar or equal to 20 km in diameter must be characterized by a shallow H-distribution slope in order to produce only these three large detections. This shallow size distribution suggests that the family formed in a graze-and-merge scenario, not a catastrophic collision.6 month embargo; published online: 26 August 2019This item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]
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