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This work is dedicated to debias the Near-Earth Object (NEO) population based on observations from the Asteroid Terrestrial-impact Last Alert System (ATLAS) telescopes. We have applied similar methods used to develop the recently released NEO model generator (NEOMOD), once debiasing the NEO population using data from Catalina Sky Survey (CSS) G96 telescope. ATLAS is composed of four different telescopes. We first analyzed observational data from each of all four telescopes separately and later combined them. Our results highlight main differences between CSS and ATLAS, e.g., sky coverage and survey power at debiasing the NEO population. ATLAS has a much larger sky coverage than CSS, allowing it to find bright NEOs that would be constantly ‘‘hiding’’ from CSS. Consequently, ATLAS is more powerful than CSS at debiasing the NEO population for H ≲ 19. With its intrinsically greater sensitivity and emphasis on observing near opposition, CSS excels in the debiasing of smaller objects. ATLAS, as an all sky survey designed to find imminent hazardous objects, necessarily spends a significant fraction of time looking at places on the sky where objects do not appear, reducing its power for debiasing the population of small objects. We estimate a NEO population completeness of ≈ 88%+3% −2% for H < 17.75 and ≈ 36%+1% −1% for H < 22.25. Those numbers are similar to previous estimates (within error bars for H < 17.75) from CSS, yet, around 3% and 8% smaller at their face values, respectively. We also confirm previous finding that the 𝜈6 secular resonance is the main source of small and faint NEOs at H = 28, whereas the 3:1 mean motion resonance with Jupiter dominates for larger and brighter NEOs at H = 15. 

Abstract Nongravitational accelerations in the absence of observed activity have recently been identified on near-Earth objects (NEOs), opening the question of the prevalence of anisotropic mass loss in the near-Earth environment. Motivated by the necessity of nongravitational accelerations to identify 2010 VL₆₅and 2021 UA₁₂as a single object, we investigate the problem of linking separate apparitions in the presence of nongravitational perturbations. We find that nongravitational accelerations on the order of 1 × 10^–9au day⁻²can lead to a change in plane-of-sky positions of ∼1 × 10³arcsec between apparitions. Moreover, we inject synthetic tracklets of hypothetical nongravitationally accelerating NEOs into the Minor Planet Center orbit identification algorithms. We find that at large nongravitational accelerations (∣A_i∣ ≥ 1 × 10⁻⁸au day⁻²) these algorithms fail to link a significant fraction of these tracklets. We further show that if orbits can be determined for both apparitions, the tracklets will be linked regardless of nongravitational accelerations, although they may be linked to multiple objects. In order to aid in the identification and linkage of nongravitationally accelerating objects, we propose and test a new methodology to search for unlinked pairs. When applied to the current census of NEOs, we recover the previously identified case but identify no new linkages. We conclude that current linking algorithms are generally robust to nongravitational accelerations, but objects with large nongravitational accelerations may potentially be missed. While current algorithms are well-positioned for the anticipated increase in the census population from future survey missions, it may be possible to find objects with large nongravitational accelerations hidden in isolated tracklet pairs. 

Small bodies are capable of delivering essential prerequisites for the development of life, such as volatiles and organics, to the terrestrial planets. For example, empirical evidence suggests that water was delivered to the Earth by hydrated planetesimals from distant regions of the Solar System. Recently, several morphologically inactive near-Earth objects were reported to experience significant nongravitational accelerations inconsistent with radiation-based effects, and possibly explained by volatile-driven outgassing. However, these “dark comets” display no evidence of comae in archival images, which are the defining feature of cometary activity. Here, we report detections of nongravitational accelerations on seven additional objects classified as inactive (doubling the population) that could also be explainable by asymmetric mass loss. A detailed search of archival survey and targeted data rendered no detection of dust activity in any of these objects in individual or stacked images. We calculate dust production limits of $\sim$10, $0.1$, and $0.1$kg s ${}^{-1}$for 1998 FR ${}_{11}$, 2001 ME ${}_1$, and 2003 RM with these data, indicating little or no dust surrounding the objects during the observations. This set of dark comets reveals the delineation between two distinct populations: larger, “outer” dark comets on eccentric orbits that are end members of a continuum in activity level of comets, and smaller, “inner” dark comets on near-circular orbits that could signify a different different population. These objects may trace various stages in the life cycle of a previously undetected, but potentially numerous, volatile-rich population that may have provided essential material to the Earth. 

Our previous model (NEOMOD2) for the orbital and absolute magnitude distribution of Near Earth Objects (NEOs) was calibrated on the Catalina Sky Survey observations between 2013 and 2022. Here we extend NEOMOD2 to include visible albedo information from the Wide-Field Infrared Survey Explorer. The debiased albedo distribution of NEOs can be approximated by the sum of two Rayleigh distributions with the scale parameters 𝑝V,dark ≃ 0.03 and 𝑝V,bright ≃ 0.17. We find evidence for smaller NEOs having (on average) higher albedos than larger NEOs; this is likely a consequence of the size-dependent sampling of different main belt sources. These inferences and the absolute magnitude distribution from NEOMOD2 are used to construct the debiased size distribution of NEOs. We estimate 830±60 NEOs with diameters 𝐷 > 1 km and 20,000±2,000 NEOs with 𝐷 > 140 m. The new model, NEOMOD3, is available via the NEOMOD Simulator — an easy-to-operate code that can be used to generate user-defined samples (orbits, sizes and albedos) from the model. 

Abstract We derive purely gravitational constraints on dark matter and cosmic neutrino profiles in the solar system using asteroid (101955) Bennu. We focus on Bennu because of its extensive tracking data and high-fidelity trajectory modeling resulting from the OSIRIS-REx mission. We find that the local density of dark matter is bound byρ_DM ≲ 3.3 × 10^-15 kg/m³ ≃ 6 × 10⁶ ρ̅_DM, in the vicinity of ∼ 1.1 au (where ρ̅_DM ≃ 0.3 GeV/cm³). We show that high-precision tracking data of solar system objects can constrain cosmic neutrino overdensities relative to the Standard Model prediction n̅_ν, at the level ofη ≡ n_ν/n̅_ν ≲ 1.7 × 10¹¹(0.1 eV/m_ν) (Saturn), comparable to the existing bounds from KATRIN and other previous laboratory experiments (withm_νthe neutrino mass). These local bounds have interesting implications for existing and future direct-detection experiments. Our constraints apply to all dark matter candidates but are particularly meaningful for scenarios including solar halos, stellar basins, and axion miniclusters, which predict overdensities in the solar system. Furthermore, introducing a DM-SM long-range fifth force with a strength α̃_Dtimes stronger than gravity, Bennu can set a constraint onρ_DM ≲ ρ̅_DM(6 × 10⁶/α̃_D). These constraints can be improved in the future as the accuracy of tracking data improves, observational arcs increase, and more missions visit asteroids. 

Catalina Sky Survey (CSS) is a major survey of Near-Earth Objects (NEOs). In a recent work, we used CSS observations from 2005–2012 to develop a new population model of NEOs (NEOMOD). CSS’s G96 telescope was upgraded in 2016 and detected over 10,000 unique NEOs since then. Here we characterize the NEO detection efficiency of G96 and use G96’s NEO detections from 2013–2022 to update NEOMOD. This resolves previous model inconsistencies related to the population of large NEOs. We estimate there are 936 ± 29 NEOs with absolute magnitude 𝐻 < 17.75 (diameter 𝐷 > 1 km for the reference albedo 𝑝V = 0.14) and semimajor axis 𝑎 < 4.2 au. The slope of the NEO size distribution for 𝐻 = 25–28 is found to be relatively shallow (cumulative index ≃ 2.6) and the number of 𝐻 < 28 NEOs (𝐷 > 9 m for 𝑝V = 0.14) is determined to be (1.20 ± 0.04) × 107 , about 3 times lower than in Harris & Chodas (2021). Small NEOs have a different orbital distribution and higher impact probabilities than large NEOs. We estimate 0.034 ± 0.002 impacts of 𝐻 < 28 NEOs on the Earth per year, which is near the low end of the impact flux range inferred from atmospheric bolide observations. Relative to a model where all NEOs are delivered directly from the main belt, the population of small NEOs detected by G96 shows an excess of low-eccentricity orbits with 𝑎 ≃ 1–1.6 au that appears to increase with 𝐻 (≃ 30% excess for 𝐻 = 28). We suggest that the population of very small NEOs is boosted by tidal disruption of large NEOs during close encounters to the terrestrial planets. When the effect of tidal disruption is (approximately) accounted for in the model, we estimate 0.06 ± 0.01 impacts of 𝐻 < 28 NEOs on the Earth per year, which is more in line with the bolide data. The impact probability of a 𝐻 < 22 (𝐷 > 140 m for 𝑝V = 0.14) object on the Earth in this millennium is estimated to be ≃ 4.5%