J/AJ/156/33 Resonance sticking in the population of scattering TNOs (Yu+, 2018)
Trans-Neptunian objects transiently stuck in Neptune's mean-motion resonances:
numerical simulations of the current population.
Yu T.Y.M., Murray-Clay R., Volk K.
<Astron. J., 156, 33 (2018)>
=2018AJ....156...33Y 2018AJ....156...33Y (SIMBAD/NED BibCode)
ADC_Keywords: Solar system ; Minor planets ; Models, evolutionary
Keywords: Kuiper belt: general
Abstract:
A substantial fraction of our solar system's trans-Neptunian objects
(TNOs) are in mean-motion resonance with Neptune. Many of these objects
were likely caught into resonances by planetary migration-either smooth
or stochastic- approximately 4 Gyr ago. Some, however, gravitationally
scattered off of Neptune and became transiently stuck in more recent
events. Here we use numerical simulations to predict the number of
transiently stuck objects, captured from the current actively scattering
population, that occupy 111 resonances at semimajor axes a=30-100 au.
Our source population is an observationally constrained model of the
currently scattering TNOs. We predict that, integrated across all
resonances at these distances, the current transient-sticking population
comprises 40% of the total transiently stuck+scattering TNOs, suggesting
that these objects should be treated as a single population. We compute
the relative distribution of transiently stuck objects across all p:q
resonances with 1/6=<q/p=<1, p<40, and q<20, providing predictions for
the population of transient objects with Hr<8.66 in each resonance.
We find that the relative populations are approximately proportional
to each resonance's libration period and confirm that the importance
of transient sticking increases with semimajor axis in the studied
range. We calculate the expected distribution of libration amplitudes
for stuck objects and demonstrate that observational constraints
indicate that both the total number and the amplitude distribution of
5:2 resonant TNOs are inconsistent with a population dominated by
transient sticking from the current scattering disk. The 5:2 resonance
hence poses a challenge for leading theories of Kuiper Belt sculpting.
Description:
To determine the orbital distribution of currently resonant objects
that may be attributed to transient sticking from today's population
of scattering trans-Neptunian objects (TNOs), we perform a series of
numerical simulations. We use a model of the current scattering
population (see Gladman et al. 2008ssbn.book...43G 2008ssbn.book...43G for a detailed
definition of this population) for our initial conditions. Following
Alexandersen et al. (2013Sci...341..994A 2013Sci...341..994A) and Shankman et al.
(2013ApJ...764L...2S 2013ApJ...764L...2S), we use initial conditions from a scattering
population simulated in Kaib et al. (2011Icar..215..491K 2011Icar..215..491K), with
inclinations adjusted to reflect a dynamically hotter initial disk of
particles. We are interested in resonance sticking at all timescales,
from 105 yr (a few libration periods for close-in resonances) to the
age of the solar system. However, the total population of scattering
TNOs has decayed over time. We thus restrict ourselves to 109 yr
timescales and treat any remnant resonant TNOs that were "transiently"
stuck more than 1 Gyr ago as part of the primordial (i.e., not
modeled) population.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 50 7 Number of simulated particles experiencing
sticking at 30<a<100 au
table2.dat 157 195 Time spent by simulated particles between
30<a<100 au: total and by resonance
table3.dat 59 194 Summary of normalized transient resonance
fractions and predicted absolute transient
sticking populations for the range 30<a<100 au
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See also:
B/astorb : Orbits of Minor Planets (Bowell+ 2010)
J/ApJS/189/336 : HST astrometry of TNOs (Benecchi+, 2010)
J/AJ/152/111 : A 2011-2013 survey of trans-Neptunian objects
(Alexandersen+, 2016)
J/AJ/152/221 : New extreme trans-Neptunian objects (Sheppard+, 2016)
Byte-by-byte Description of file: table1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1 I1 --- SimID [1/3] Simulation identifier
2 A1 --- f_SimID [d] Flag indicating data in Table 2 for this
simulation identifier
4- 9 E6.2 yr Length [1.5e+07/1e+09] Simulation length
11- 14 E4.1 yr Res [100000/1e+07] Minimum stick resolution
16- 19 I4 --- Npart1 [3393/5126] Number of unique particles in
a range (1)
21- 24 I4 --- Npart2 [2310/2629] Number of unique particles with
≥1 stick
26- 29 E4.1 yr b_Time [100000/1e+08] Lower value of stick timescale
31- 36 E6.2 yr B_Time [1e+06/1e+09] Upper value of stick timescale
38- 42 I5 --- NstickA [52/22493] Absolute number of sticks
44- 50 I7 --- NstickN [733/1499533] Number of sticks normalized to
account for the overall simulation length
and test particle loss
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Note (1): All simulations began with 8500 scattering test particles (see
Section 2.1 for a description of their initial conditions). The number of
unique particles in the range refers to the number of those 8500 test
particles that enter the range 30<a<100 au at any time during the simulation.
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Byte-by-byte Description of file: table2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 3 A3 --- p p resonance (1)
5- 7 A3 --- q q resonance (1)
9- 13 I5 ct Sticks-1 [0/24089] Number of sticks for simulation 1
15- 32 E18.12 yr Time-1 [0/38592541400] Total stick time for
simulation 1
34- 51 E18.12 --- Frac-1 [0/1] Time-weighted fraction for simulation 1
53- 57 I5 ct Sticks-2 [0/11348] Number of sticks for simulation 2
59- 76 E18.12 yr Time-2 [0/237079001000] Total stick time for
simulation 2
78- 95 E18.12 --- Frac-2 [0/1] Time-weighted fraction for simulation 2
97-100 I4 ct Sticks-3 [0/7083] Number of sticks for simulation 3
102-119 E18.12 yr Time-3 [0/1.53388095e+12] Total stick time for
simulation 3
121-138 E18.12 --- Frac-3 [0/1] Time-weighted fraction for simulation 3
140-157 E18.12 --- Frac-comb [2.36208182773e-06/1] Time-weighted fraction
for 3 combined
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Note (1): The first line, where p=q='na' indicates the entire scattering+stuck
population. The last line where p=q='all' indicates the entire stuck
population.
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Byte-by-byte Description of file: table3.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 3 A3 --- p p resonance (1)
5- 7 A3 --- q q resonance (1)
9- 13 F5.2 AU a [0/99.26] Semimajor axis
15- 26 E12.6 --- fsr [2.362082e-06/0.4032886] Fraction of
scattering+stuck population
28- 39 E12.6 --- fr [5.857051e-06/1] Fraction of stuck population
41- 52 E12.6 --- fs [3.958499e-06/0.6758519] Fraction of scattering
population
54- 59 F6.1 ct N [0/7434.4] Predicted number with an H-magnitude cut
Hr<8.66
--------------------------------------------------------------------------------
Note (1): The first line where p=q='all' indicates the entire stuck population
in the range 30<a<100 au.
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History:
From electronic version of the journal
(End) Prepared by [AAS], Tiphaine Pouvreau [CDS] 21-Jan-2019