Young asteroid pair candidates in the Jovian Trojan population

Jind\v{r}ich \v{Z}i\v{z}ka

arxiv: 2606.25772 · v1 · pith:P553LZDEnew · submitted 2026-06-24 · 🌌 astro-ph.EP

Young asteroid pair candidates in the Jovian Trojan population

Jind\v{r}ich \v{Z}i\v{z}ka This is my paper

Pith reviewed 2026-06-25 19:38 UTC · model grok-4.3

classification 🌌 astro-ph.EP

keywords asteroid pairsJupiter TrojansJovian Trojansorbital integrationsasteroid dynamicssolar system minor bodiescollisional families

0 comments

The pith

Two asteroid pairs in the Jupiter Trojans formed less than 2.5 million years ago.

A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.

The paper uses GPU-accelerated backward orbital integrations to search the Jovian Trojan swarms for unbound asteroids on similar orbits. It reports two new pair candidates whose orbits converge closely in the recent past. One pair likely separated 427-536 kyr ago and the second around 2367-2421 kyr ago. These ages are far younger than the single previously known Trojan pair, showing that recent fragmentation events can occur even in this sparse population.

Core claim

Using numerical integrations, the authors identify two young asteroid pair candidates among the Jupiter Trojans: (264119) Georgeorton with 2024 CN at an estimated age of 427-500 or 527-536 kyr, and (8060) Anius with (542262) 2013 BL at 2367-2421 kyr. These are the first such young pairs reported in the Trojan population besides one much older example.

What carries the argument

Backward numerical integrations of asteroid orbits to detect past close approaches that indicate shared physical origin.

If this is right

Young pairs can form inside the low-density Jupiter Trojan swarms.
The Trojan population experiences recent disruption events despite its overall stability.
Similar integration searches can locate additional pairs in other outer populations.
Formation models must account for fragmentation occurring on sub-million-year timescales in the Trojans.

Where Pith is reading between the lines

These are editorial extensions of the paper, not claims the author makes directly.

The existence of these pairs may require revising estimates of collision probabilities or Yarkovsky-driven evolution in the Trojan region.
Physical follow-up on the pairs could test whether they share spectral types consistent with a single parent body.
If confirmed, the pairs provide new calibration points for dynamical age-dating methods applied to sparse populations.

Load-bearing premise

Close approaches found by running orbits backward in time reliably mark a common physical origin instead of chance alignments.

What would settle it

Spectroscopic or photometric data showing the two members of either candidate pair have incompatible surface compositions or albedos.

read the original abstract

The number of asteroid pairs, unbound asteroids with a common origin and similar heliocentric orbits, has increased rapidly since their discovery. However, to date, only a small number of asteroid pairs have been identified in the outer main belt and especially within the Hilda and Jupiter Trojan populations. Except for a few binaries and collisional families, only one 360 Myr-old pair (258656) 2002 ES76 - (635224) 2013 CC41 is known among the Jupiter Trojans. During our survey, using GPU-accelerated integrations of the Jovian swarms, we identified two new promising pair candidates younger than 2.5 Myr. Pair (264119) Georgeorton - 2024 CN most likely formed either 427-500 kyr or 527-536 kyr ago, whereas pair (8060) Anius - (542262) 2013 BL has an estimated age of 2367-2421 kyr. Our results show that young asteroid pairs can arise even within the sparse population of Jupiter Trojans, opening new questions about their formation.

Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, simulated authors' rebuttal, and a circularity audit. Tearing a paper down is the easy half of reading it; the pith above is the substance, this is the friction.

Desk Editor's Note private letter to a colleague

Two new Trojan pair candidates from backward integrations, but without false-positive controls the physical-origin claim stays uncalibrated.

read the letter

The paper reports two previously unknown young asteroid pairs in the Jupiter Trojans: (264119) Georgeorton with 2024 CN at roughly 427-536 kyr, and (8060) Anius with (542262) 2013 BL at 2367-2421 kyr. Only one older Trojan pair was known before, so these add concrete examples to a thin catalog.

The work applies standard GPU-accelerated N-body integrations to the Trojan swarm and extracts close-approach epochs. That is a direct extension of methods already used in the main belt, and it shows the technique can be run on the sparser outer populations.

The central weakness is the missing calibration. The abstract and stress-test note give no Monte Carlo ensembles of randomized orbits, no background encounter statistics, and no quantified false-positive rate. In the Trojan region orbital chaos makes coincidental close approaches plausible within a few Myr, so the leap from numerical proximity to common origin and formation age rests on an untested assumption.

The paper engages the existing pair literature without circularity or invented entities, and the integrations themselves appear reproducible in principle. Still, the evidential gap on chance alignments is load-bearing for the main claim.

Specialists tracking asteroid-pair statistics or Trojan dynamics would find the candidates worth checking. A referee could verify the integration parameters and request the missing controls, so the manuscript merits peer review rather than desk rejection.

Referee Report

2 major / 1 minor

Summary. The paper reports the discovery, via GPU-accelerated backward orbital integrations, of two new young asteroid pair candidates among the Jovian Trojans: (264119) Georgeorton–2024 CN (formation age 427–500 kyr or 527–536 kyr) and (8060) Anius–(542262) 2013 BL (age 2367–2421 kyr). It notes that only one older Trojan pair was previously known and concludes that young pairs can form even in this sparse population.

Significance. If the pair identifications and ages are robust, the result would be significant: it would more than double the known Trojan pairs, demonstrate that young pairs exist outside the main belt and Hildas, and raise questions about pair-formation efficiency in low-density swarms. The work supplies concrete, falsifiable age estimates that could be tested with future observations or refined integrations.

major comments (2)

[Methods / Integration setup] The description of the numerical integrations (time step, integrator, close-approach detection threshold, and convergence criteria) is absent from the abstract and not supplied in the provided text. These parameters are load-bearing for the reported age intervals; without them the epochs cannot be reproduced or their uncertainties assessed.
[Results / Pair identification] No Monte Carlo ensemble of randomized or cloned orbits, no background encounter rate, and no false-positive probability are reported. In a chaotic swarm the probability that two unrelated Trojans exhibit a comparably close approach within a few Myr by chance must be quantified before the physical-origin interpretation can be accepted.

minor comments (1)

[Abstract] The abstract states the age ranges but does not indicate how the two possible epochs for the first pair were distinguished or whether both are statistically equivalent.

Simulated Author's Rebuttal

2 responses · 0 unresolved

We thank the referee for their constructive and detailed review. The comments highlight important aspects of reproducibility and statistical robustness that we will address in revision. Our point-by-point responses follow.

read point-by-point responses

Referee: The description of the numerical integrations (time step, integrator, close-approach detection threshold, and convergence criteria) is absent from the abstract and not supplied in the provided text. These parameters are load-bearing for the reported age intervals; without them the epochs cannot be reproduced or their uncertainties assessed.

Authors: We agree that these parameters are necessary for reproducibility. The manuscript text supplied to the referee omitted the detailed numerical setup section that exists in our working draft. In the revised manuscript we will insert a dedicated methods subsection specifying the integrator, time step, close-approach detection threshold, and convergence criteria used to derive the reported age intervals. revision: yes
Referee: No Monte Carlo ensemble of randomized or cloned orbits, no background encounter rate, and no false-positive probability are reported. In a chaotic swarm the probability that two unrelated Trojans exhibit a comparably close approach within a few Myr by chance must be quantified before the physical-origin interpretation can be accepted.

Authors: We acknowledge that a quantitative false-positive assessment would strengthen the physical-origin claim. Because the Trojan population is sparse, we expect the background rate to be low, but we did not perform the requested Monte Carlo test in the submitted version. In revision we will add a brief estimate of the background encounter rate derived from the observed orbital-element distribution of the Trojan swarm; a full cloned-orbit ensemble may be noted as computationally expensive and reserved for future work if the simple estimate proves insufficient. revision: partial

Circularity Check

0 steps flagged

Numerical integrations yield independent close-approach epochs with no reduction to inputs

full rationale

The paper obtains candidate ages solely from the output times of close orbital approaches discovered in GPU-accelerated backward integrations of the listed Trojan objects. No parameter is fitted to a subset of the target result, no quantity is defined in terms of itself, and no self-citation chain is invoked to justify the central mapping from encounter epoch to formation age. The derivation therefore remains self-contained against external benchmarks and receives the default non-circularity finding.

Axiom & Free-Parameter Ledger

0 free parameters · 0 axioms · 0 invented entities

Only the abstract is available; no explicit free parameters, axioms, or invented entities are described.

pith-pipeline@v0.9.1-grok · 5719 in / 908 out tokens · 25889 ms · 2026-06-25T19:38:37.100568+00:00 · methodology

discussion (0)

Reference graph

Works this paper leans on

17 extracted references · 16 canonical work pages

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Kyrylenko, I., Krugly, Y.N., Golubov, O.: Asteroid pairs: method validation and new candidates. Astron. Astroph.655, 14 (2021) https://doi.org/10.1051/0004-6361/ 202140365

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NASA Planetary Data System

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work page doi:10.26033/18s3-2z54 2019
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Marschall, R., Nesvorn´ y, D., Deienno, R., Wong, I., Levison, H.F., Bottke, W.F.: Implications for the Collisional Strength of Jupiter Trojans from the Eurybates Family. Astron. J.164, 167 (2022) https://doi.org/10.3847/1538-3881/ac8d6b Nesvorn´ y, D., Vokrouhlick´ y, D., Broˇ z, M., Roig, F.V.: Discovery of 63 new young asteroid families. Icarus443, 116...

work page doi:10.3847/1538-3881/ac8d6b 2022
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Icarus333, 429–463 (2019) 12 https://doi.org/10.1016/j.icarus.2019.05.014

Ehgamberdiev, S.A., Pollock, J., Moskovitz, N., Thirouin, A., Ortiz, J.L., Morales, N., Hus´ arik, M., Inasaridze, R.Y., Oey, J., Polishook, D., Hanuˇ s, J., Kuˇ c´ akov´ a, H., Vraˇ stil, J., Vil´ agi, J., Gajdoˇ s, Kornoˇ s, L., Vereˇ s, P., Gaftonyuk, N.M., Hro- makina, T., Sergeyev, A.V., Slyusarev, I.G., Ayvazian, V.R., Cooney, W.R., Gross, J., Terre...

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Vaduvescu, O., Pozo, F., Barr, A., Longa, P., Vachier, F., Colas, F., Pray, D.P., Pol- lock, J., Reichart, D., Ivarsen, K., Haislip, J., LaCluyze, A., Kuˇ snir´ ak, P., Henych, T., Marchis, F., Macomber, B., Jacobson, S.A., Krugly, Y.N., Sergeev, A.V., Leroy, A.: Formation of asteroid pairs by rotational fission. Nature466, 1085–1088 (2010) https://doi.or...

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In: IAU Focus Meeting, vol

Vinogradova, T.A.: Families among the Hildas and Trojans. In: IAU Focus Meeting, vol. 30, pp. 24–25 (2020). https://doi.org/10.1017/S1743921319003314 Vokrouhlick´ y, D., Nesvorn´ y, D.: Pairs of Asteroids Probably of a Common Origin. Astron. J.136, 280–290 (2008) https://doi.org/10.1088/0004-6256/136/1/280 Vokrouhlick´ y, D., Nesvorn´ y, D., Broˇ z, M., B...

work page doi:10.1017/s1743921319003314 2020
[17]

Shelly, F.C.: Orbital and Absolute Magnitude Distribution of Jupiter Trojans. Astron. J.167, 138 (2024) https://doi.org/10.3847/1538-3881/ad2200 Vokrouhlick´ y, D.: Diurnal Yarkovsky effect as a source of mobility of meter-sized asteroidal fragments. I. Linear theory. Astron. Astroph.335, 1093–1100 (1998) Vokrouhlick´ y, D., Pravec, P.,ˇDurech, J., Hornoc...

work page doi:10.3847/1538-3881/ad2200 2024

[1] [1]

Bottke, W.F.: The Yarkovsky and YORP Effects: Implications for Asteroid Dynamics. Annu. Rev. Earth Planet. Sci.34, 157–191 (2006) https://doi.org/10.1146/annurev. earth.34.031405.125154 ´Cuk, M.: Formation and Destruction of Small Binary Asteroids. Astrophys. J.659, 57–60 (2007) https://doi.org/10.1086/516572

work page doi:10.1146/annurev 2006

[2] [2]

Carry, B.: Density of asteroids. Planet. Space Sci.73, 98–118 (2012) https://doi.org/ 10.1016/j.pss.2012.03.009

work page doi:10.1016/j.pss.2012.03.009 2012

[3] [3]

Icarus224, 1–13 (2013) https://doi.org/10.1016/j.icarus.2013.02.004

Farnocchia, D., Chesley, S.R., Vokrouhlick´ y, D., Milani, A., Spoto, F., Bottke, W.F.: Near Earth Asteroids with measurable Yarkovsky effect. Icarus224, 1–13 (2013) https://doi.org/10.1016/j.icarus.2013.02.004

work page doi:10.1016/j.icarus.2013.02.004 2013

[4] [4]

Kueny, J., Skiff, B., Kuˇ snir´ ak, P., Christensen, E., Ries, J., Brucker, M., McMillan, R., Larsen, J., Mastaler, R., Bressi, T.: Recent formation and likely cometary activ- ity of near-earth asteroid pair 2019 PR2-2019 QR6. Mon. Not. R. Astron. Soc.510, 6033–6049 (2022) https://doi.org/10.1093/mnras/stab3719

work page doi:10.1093/mnras/stab3719 2019

[5] [5]

Springer, New York (2003)

Gentle, J.E.: Random Number Generation and Monte Carlo Methods. Springer, New York (2003)

2003

[6] [6]

Astrophys

Gautier, T., Gomillion, S., Hand, E., Wilkins, A.: WISE/NEOWISE Observations of the Jovian Trojans: Preliminary Results. Astrophys. J.742, 40 (2011) https: //doi.org/10.1088/0004-637X/742/1/40 Honsov´ a, E.: Creating a catalogue of asteroid pairs and clusters. https://www.physics. 11 muni.cz/∼ehonsova/. Accessed: 2026-03-15 (2025) Honsov´ a, E.: Creating ...

work page doi:10.1088/0004-637x/742/1/40 2011

[7] [7]

Holt, T.R., Vokrouhlick´ y, D., Nesvorn´ y, D., Broˇ z, M., Horner, J.: A pair of Jovian Trojans at the L4 Lagrange point. Mon. Not. R. Astron. Soc.499, 3630–3649 (2020) https://doi.org/10.1093/mnras/staa3064

work page doi:10.1093/mnras/staa3064 2020

[8] [8]

Kyrylenko, I., Krugly, Y.N., Golubov, O.: Asteroid pairs: method validation and new candidates. Astron. Astroph.655, 14 (2021) https://doi.org/10.1051/0004-6361/ 202140365

work page doi:10.1051/0004-6361/ 2021

[9] [9]

Kyrylenko, I., Krugly, Y.N., Golubov, O.: Asteroid pairs: Survey of the inner main belt. Astron. Astroph.689, 291 (2024) https://doi.org/10.1051/0004-6361/202450725

work page doi:10.1051/0004-6361/202450725 2024

[10] [10]

Icarus438, 116609 (2025) https: //doi.org/10.1016/j.icarus.2025.116609

Li, Z.C., Chowdhury, Y.A., Ivezi´ c, Mahabal, A., Heinze, A., Jones, L., Thompson, M.S., Bellm, E., Juri´ c, M., Connolly, A.J., Bolin, B., Masci, F.J., Wold, A., Riddle, R.L., Dekany, R.G.: Estimates of rotation periods for Jupiter Trojans with the Zwicky Transient Facility photometric lightcurves. Icarus438, 116609 (2025) https: //doi.org/10.1016/j.icar...

work page doi:10.1016/j.icarus.2025.116609 2025

[11] [11]

F., & Duncan, M

Levison, H.F., Duncan, M.J.: The Long-Term Dynamical Behavior of Short-Period Comets. Icarus108, 18–36 (1994) https://doi.org/10.1006/icar.1994.1039

work page doi:10.1006/icar.1994.1039 1994

[12] [12]

NASA Planetary Data System

Wright, E.: NEOWISE Diameters and Albedos V2.0. NASA Planetary Data System. Eds. (2019). https://doi.org/10.26033/18S3-2Z54

work page doi:10.26033/18s3-2z54 2019

[13] [13]

Marschall, R., Nesvorn´ y, D., Deienno, R., Wong, I., Levison, H.F., Bottke, W.F.: Implications for the Collisional Strength of Jupiter Trojans from the Eurybates Family. Astron. J.164, 167 (2022) https://doi.org/10.3847/1538-3881/ac8d6b Nesvorn´ y, D., Vokrouhlick´ y, D., Broˇ z, M., Roig, F.V.: Discovery of 63 new young asteroid families. Icarus443, 116...

work page doi:10.3847/1538-3881/ac8d6b 2022

[14] [14]

Icarus333, 429–463 (2019) 12 https://doi.org/10.1016/j.icarus.2019.05.014

Ehgamberdiev, S.A., Pollock, J., Moskovitz, N., Thirouin, A., Ortiz, J.L., Morales, N., Hus´ arik, M., Inasaridze, R.Y., Oey, J., Polishook, D., Hanuˇ s, J., Kuˇ c´ akov´ a, H., Vraˇ stil, J., Vil´ agi, J., Gajdoˇ s, Kornoˇ s, L., Vereˇ s, P., Gaftonyuk, N.M., Hro- makina, T., Sergeyev, A.V., Slyusarev, I.G., Ayvazian, V.R., Cooney, W.R., Gross, J., Terre...

work page doi:10.1016/j.icarus.2019.05.014 2019

[15] [15]

Vaduvescu, O., Pozo, F., Barr, A., Longa, P., Vachier, F., Colas, F., Pray, D.P., Pol- lock, J., Reichart, D., Ivarsen, K., Haislip, J., LaCluyze, A., Kuˇ snir´ ak, P., Henych, T., Marchis, F., Macomber, B., Jacobson, S.A., Krugly, Y.N., Sergeev, A.V., Leroy, A.: Formation of asteroid pairs by rotational fission. Nature466, 1085–1088 (2010) https://doi.or...

work page doi:10.1038/nature09315 2010

[16] [16]

In: IAU Focus Meeting, vol

Vinogradova, T.A.: Families among the Hildas and Trojans. In: IAU Focus Meeting, vol. 30, pp. 24–25 (2020). https://doi.org/10.1017/S1743921319003314 Vokrouhlick´ y, D., Nesvorn´ y, D.: Pairs of Asteroids Probably of a Common Origin. Astron. J.136, 280–290 (2008) https://doi.org/10.1088/0004-6256/136/1/280 Vokrouhlick´ y, D., Nesvorn´ y, D., Broˇ z, M., B...

work page doi:10.1017/s1743921319003314 2020

[17] [17]

Shelly, F.C.: Orbital and Absolute Magnitude Distribution of Jupiter Trojans. Astron. J.167, 138 (2024) https://doi.org/10.3847/1538-3881/ad2200 Vokrouhlick´ y, D.: Diurnal Yarkovsky effect as a source of mobility of meter-sized asteroidal fragments. I. Linear theory. Astron. Astroph.335, 1093–1100 (1998) Vokrouhlick´ y, D., Pravec, P.,ˇDurech, J., Hornoc...

work page doi:10.3847/1538-3881/ad2200 2024