Population control of Mars Trojans by the Yarkovsky & YORP effects

Apostolos A. Christou*, G. Borisov, Aldo Dell'Oro, Seth A. Jacobson, Alberto Cellino, Eduardo Unda-Sanzana

*Corresponding author for this work

Research output: Contribution to journalArticle

Abstract

We explore the hypothesis that the population of Martian Trojans is the result of a balance between the production of new asteroids (“YORPlets”) through the YORP effect and their eventual escape from the Trojan clouds through Yarkovsky-driven orbital evolution. Our principal observables are: (5261) Eureka, its family of 8 asteroids and the family-less Trojans (101429) 1998 VF31 & (121514) 1999 UJ7. We model the population evolution as a birth-death random process and assume it is in a steady state. We then simulate the discovery of Trojans to-date and find that family members of 101429 and 121514, if they exist, are intrinsically more difficult to detect than Eureka's. Their non-discovery can be used as evidence of their non-existence only under the assumption that their brightness relative to the parent asteroid is similar to that in the Eureka family. To find out how efficiently Mars Trojans are lost from the Trojan clouds due to the Yarkovsky effect, we carry out dynamical simulations of test particles originating from these parent bodies. We find that objects originating from Eureka and 121514 begin escaping after ~1 Gyr, but that those from 101429 are already lost by that time, probably due to that asteroid's proximity to an eccentricity-type secular resonance within Mars's co-orbital region. This is the likely cause behind the absence of Trojans in the orbital vicinity of 101429. In contrast, the solitary status of 121514 points to an intrinsic inability of the asteroid to produce YORPlets during the most recent ~20% of the solar system's history, a finding potentially related to 121514’s present, low angular momentum rotational state, unless the Eureka family formed rapidly during a single fission event.

Original languageEnglish (US)
Article number113370
JournalIcarus
Volume335
DOIs
StatePublished - Jan 1 2020

Fingerprint

asteroids
asteroid
mars
Mars
orbitals
random processes
parent body
rotational states
eccentricity
death
angular momentum
solar system
escape
fission
proximity
brightness
family
effect
histories
causes

Keywords

  • Asteroids
  • Dynamics
  • Mars
  • Trojan asteroids

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

Cite this

Christou, A. A., Borisov, G., Dell'Oro, A., Jacobson, S. A., Cellino, A., & Unda-Sanzana, E. (2020). Population control of Mars Trojans by the Yarkovsky & YORP effects. Icarus, 335, [113370]. https://doi.org/10.1016/j.icarus.2019.07.004
Christou, Apostolos A. ; Borisov, G. ; Dell'Oro, Aldo ; Jacobson, Seth A. ; Cellino, Alberto ; Unda-Sanzana, Eduardo. / Population control of Mars Trojans by the Yarkovsky & YORP effects. In: Icarus. 2020 ; Vol. 335.
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abstract = "We explore the hypothesis that the population of Martian Trojans is the result of a balance between the production of new asteroids (“YORPlets”) through the YORP effect and their eventual escape from the Trojan clouds through Yarkovsky-driven orbital evolution. Our principal observables are: (5261) Eureka, its family of 8 asteroids and the family-less Trojans (101429) 1998 VF31 & (121514) 1999 UJ7. We model the population evolution as a birth-death random process and assume it is in a steady state. We then simulate the discovery of Trojans to-date and find that family members of 101429 and 121514, if they exist, are intrinsically more difficult to detect than Eureka's. Their non-discovery can be used as evidence of their non-existence only under the assumption that their brightness relative to the parent asteroid is similar to that in the Eureka family. To find out how efficiently Mars Trojans are lost from the Trojan clouds due to the Yarkovsky effect, we carry out dynamical simulations of test particles originating from these parent bodies. We find that objects originating from Eureka and 121514 begin escaping after ~1 Gyr, but that those from 101429 are already lost by that time, probably due to that asteroid's proximity to an eccentricity-type secular resonance within Mars's co-orbital region. This is the likely cause behind the absence of Trojans in the orbital vicinity of 101429. In contrast, the solitary status of 121514 points to an intrinsic inability of the asteroid to produce YORPlets during the most recent ~20{\%} of the solar system's history, a finding potentially related to 121514’s present, low angular momentum rotational state, unless the Eureka family formed rapidly during a single fission event.",
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Christou, AA, Borisov, G, Dell'Oro, A, Jacobson, SA, Cellino, A & Unda-Sanzana, E 2020, 'Population control of Mars Trojans by the Yarkovsky & YORP effects', Icarus, vol. 335, 113370. https://doi.org/10.1016/j.icarus.2019.07.004

Population control of Mars Trojans by the Yarkovsky & YORP effects. / Christou, Apostolos A.; Borisov, G.; Dell'Oro, Aldo; Jacobson, Seth A.; Cellino, Alberto; Unda-Sanzana, Eduardo.

In: Icarus, Vol. 335, 113370, 01.01.2020.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Population control of Mars Trojans by the Yarkovsky & YORP effects

AU - Christou, Apostolos A.

AU - Borisov, G.

AU - Dell'Oro, Aldo

AU - Jacobson, Seth A.

AU - Cellino, Alberto

AU - Unda-Sanzana, Eduardo

PY - 2020/1/1

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N2 - We explore the hypothesis that the population of Martian Trojans is the result of a balance between the production of new asteroids (“YORPlets”) through the YORP effect and their eventual escape from the Trojan clouds through Yarkovsky-driven orbital evolution. Our principal observables are: (5261) Eureka, its family of 8 asteroids and the family-less Trojans (101429) 1998 VF31 & (121514) 1999 UJ7. We model the population evolution as a birth-death random process and assume it is in a steady state. We then simulate the discovery of Trojans to-date and find that family members of 101429 and 121514, if they exist, are intrinsically more difficult to detect than Eureka's. Their non-discovery can be used as evidence of their non-existence only under the assumption that their brightness relative to the parent asteroid is similar to that in the Eureka family. To find out how efficiently Mars Trojans are lost from the Trojan clouds due to the Yarkovsky effect, we carry out dynamical simulations of test particles originating from these parent bodies. We find that objects originating from Eureka and 121514 begin escaping after ~1 Gyr, but that those from 101429 are already lost by that time, probably due to that asteroid's proximity to an eccentricity-type secular resonance within Mars's co-orbital region. This is the likely cause behind the absence of Trojans in the orbital vicinity of 101429. In contrast, the solitary status of 121514 points to an intrinsic inability of the asteroid to produce YORPlets during the most recent ~20% of the solar system's history, a finding potentially related to 121514’s present, low angular momentum rotational state, unless the Eureka family formed rapidly during a single fission event.

AB - We explore the hypothesis that the population of Martian Trojans is the result of a balance between the production of new asteroids (“YORPlets”) through the YORP effect and their eventual escape from the Trojan clouds through Yarkovsky-driven orbital evolution. Our principal observables are: (5261) Eureka, its family of 8 asteroids and the family-less Trojans (101429) 1998 VF31 & (121514) 1999 UJ7. We model the population evolution as a birth-death random process and assume it is in a steady state. We then simulate the discovery of Trojans to-date and find that family members of 101429 and 121514, if they exist, are intrinsically more difficult to detect than Eureka's. Their non-discovery can be used as evidence of their non-existence only under the assumption that their brightness relative to the parent asteroid is similar to that in the Eureka family. To find out how efficiently Mars Trojans are lost from the Trojan clouds due to the Yarkovsky effect, we carry out dynamical simulations of test particles originating from these parent bodies. We find that objects originating from Eureka and 121514 begin escaping after ~1 Gyr, but that those from 101429 are already lost by that time, probably due to that asteroid's proximity to an eccentricity-type secular resonance within Mars's co-orbital region. This is the likely cause behind the absence of Trojans in the orbital vicinity of 101429. In contrast, the solitary status of 121514 points to an intrinsic inability of the asteroid to produce YORPlets during the most recent ~20% of the solar system's history, a finding potentially related to 121514’s present, low angular momentum rotational state, unless the Eureka family formed rapidly during a single fission event.

KW - Asteroids

KW - Dynamics

KW - Mars

KW - Trojan asteroids

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Christou AA, Borisov G, Dell'Oro A, Jacobson SA, Cellino A, Unda-Sanzana E. Population control of Mars Trojans by the Yarkovsky & YORP effects. Icarus. 2020 Jan 1;335. 113370. https://doi.org/10.1016/j.icarus.2019.07.004