Search for L5 Earth Trojans with DECam

Markwardt, Larissa; Gerdes, D. W.; Malhotra, Renu; Becker, Juliette; Hamilton, S.; Adams, Fred C.

doi:10.1093/mnras/staa232

Cited by 25 publications

(32 citation statements)

References 33 publications

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“…Although no primordial ETs has been found yet, some constraints have been provided on their population. The most recent and restrictive values on their magnitude limit for L4 14 are N E T < 1 for H = 13.93, N E T < 10 for H = 16, and N E T < 938 for H = 22, while for L5 13 are N E T < 1 for H < 15.5, N E T = 60 − 85 for H < 19.7, and N E T = 97 for H = 20.4.…”

Section: Discussionmentioning

confidence: 99%

Orbital stability analysis and photometric characterization of the second Earth Trojan asteroid 2020 XL5

et al. 2022

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Trojan asteroids are small bodies orbiting around the L4 or L5 Lagrangian points of a Sun-planet system. Due to their peculiar orbits, they provide key constraints to the Solar System evolution models. Despite numerous dedicated observational efforts in the last decade, asteroid 2010 TK7 has been the only known Earth Trojan thus far. Here we confirm that the recently discovered 2020 XL5 is the second transient Earth Trojan known. To study its orbit, we used archival data from 2012 to 2019 and observed the object in 2021 from three ground-based observatories. Our study of its orbital stability shows that 2020 XL5 will remain in L4 for at least 4 000 years. With a photometric analysis we estimate its absolute magnitude to be $${H}_{r}=18.5{8}_{-0.15}^{+0.16}$$ H r = 18.5 8 − 0.15 + 0.16 , and color indices suggestive of a C-complex taxonomy. Assuming an albedo of 0.06 ± 0.03, we obtain a diameter of 1.18 ± 0.08 km, larger than the first known Earth Trojan asteroid.

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Section: Discussionmentioning

confidence: 99%

Orbital stability analysis and photometric characterization of the second Earth Trojan asteroid 2020 XL5

et al. 2022

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“…A new method for estimating the absolute magnitude frequency distribution of NEAs, based on observations around opposition for a sample of 13 466 NEAs was developed, which includes the smaller but deeper DECam NEO Survey (Valdes 2018(Valdes , 2019. Markwardt et al (2020) undertook a deep search (limiting magnitude V ∼ 25) of Earth Trojans in 24 sq. degrees around the L5 point.…”

Section: Des and Decam Surveysmentioning

confidence: 99%

Dozens of virtual impactor orbits eliminated by the EURONEAR VIMP DECam data mining project

Văduvescu

Curelaru

Popescu

et al. 2020

A&A

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Context. Massive data mining of image archives observed with large etendue facilities represents a great opportunity for orbital amelioration of poorly known virtual impactor asteroids (VIs). There are more than 1000 VIs known today; most of them have very short observed arcs and many are considered lost as they became extremely faint soon after discovery. Aims. We aim to improve the orbits of VIs and eliminate their status by data mining the existing image archives. Methods. Within the European Near Earth Asteroids Research (EURONEAR) project, we developed the Virtual Impactor search using Mega-Precovery (VIMP) software, which is endowed with a very effective (fast and accurate) algorithm to predict apparitions of candidate pairs for subsequent guided human search. Considering a simple geometric model, the VIMP algorithm searches for any possible intersection in space and time between the positional uncertainty of any VI and the bounding sky projection of any image archive. Results. We applied VIMP to mine the data of 451,914 Blanco/DECam images observed between 12 September 2012 and 11 July 2019, identifying 212 VIs that possibly fall into 1286 candidate images leading to either precovery or recovery events. Following a careful search of candidate images, we recovered and measured 54 VIs in 183 DECam images. About 4,000 impact orbits were eliminated from both lists, 27 VIs were removed from at least one list, while 14 objects were eliminated from both lists. The faintest detections were around V ∼ 24.0, while the majority fall between 21 < V < 23. The minimal orbital intersection distances remains constant for 67% detections, increasing for eight objects and decreasing for ten objects. Most eliminated VIs (70%) had short initial arcs of less than five days. Some unexpected photometric discovery has emerged regarding the rotation period of 2018 DB, based on the close inspection of longer trailed VIs and the measurement of their fluxes along the trails. Conclusions. Large etendue imaging archives represent great assets to search for serendipitous encounters of faint asteroids and VIs.

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“…Recently, Zhou et al (2019) concluded that the dynamical erosion over 4 Gyr, especially when accounting for Yarkovsky drift, would eliminate a population of sub-km primordial Earth co-orbitals surviving to the present day, but that km-sized could survive. Direct observational searches by Cambioni et al (2018) and Markwardt et al (2020) provided no Trojan detections down to sizes of a few hundred meters, leading to the conclusion that it is unlikely that any Earth Trojans still exist. Thus, simply demonstrating that the dynamics permit a portion of phase space to be stable does not imply that a population currently exists; again, the perturbations inherent in planet formation likely resulted in no large stable Earth co-orbitals being present at the end of planet formation.…”

Section: Hypothetical Long-lived Regionsmentioning

confidence: 99%

Four Billion Year Stability of the Earth-Mars Belt

Huang,

Gladman

2020

Preprint

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Previous work has demonstrated orbital stability for 100 Myr of initially near-circular and coplanar small bodies in a region termed the 'Earth-Mars belt' from 1.08 au < 𝑎 < 1.28 au. Via numerical integration of 3000 particles, we studied orbits from 1.04-1.30 au for the age of the Solar system. We show that on this time scale, except for a few locations where meanmotion resonances with Earth affect stability, only a narrower 'Earth-Mars belt' covering 𝑎 ∼ (1.09, 1.17) au, 𝑒 < 0.04, and 𝐼 < 1 • has over half of the initial orbits survive for 4.5 Gyr. In addition to mean-motion resonances, we are able to see how the 𝜈 3 , 𝜈 4 , and 𝜈 6 secular resonances contribute to long-term instability in the outer (1.17-1.30 au) region on Gyr time scales. We show that all of the (rather small) near-Earth objects (NEOs) in or close to the Earth-Mars belt appear to be consistent with recently arrived transient objects by comparing to a NEO steady-state model. Given the < 200 m scale of these NEOs, we estimated the Yarkovsky drift rates in semimajor axis, and use these to estimate that primordial asteroids with a diameter of 100 km or larger in the Earth-Mars belt would likely survive. We conclude that only a few 100-km sized asteroids could have been present in the belt's region at the end of the terrestrial planet formation.

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Search for L5 Earth Trojans with DECam

Cited by 25 publications

References 33 publications

Orbital stability analysis and photometric characterization of the second Earth Trojan asteroid 2020 XL5

Orbital stability analysis and photometric characterization of the second Earth Trojan asteroid 2020 XL5

Dozens of virtual impactor orbits eliminated by the EURONEAR VIMP DECam data mining project

Four Billion Year Stability of the Earth-Mars Belt

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