Astronomy
Ivana Milić Žitnik
9 papers · 1 Must Read · 2008–2024
Last updated Mar 17, 2026
Sorted by publication date, newest first. New papers are marked so you can spot recent additions.
L. Liberato, P. Tanga, D. Mary et al. · 2024 · Astronomy & Astrophysics
This study details a specialized period-detection algorithm and presents its application to the Gaia DR3 catalog. The technique identifies periodic signatures by analyzing the post-fit residuals of the calculated orbits.
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Matija Ćuk, Harrison Agrusa, Rachel H. Cueva et al. · 2024 · The Planetary Science Journal
DART data motivate weaker, size-dependent BYORP and episodic “landslide” dissipation as key drivers of small-binary evolution.
Using DART’s detailed view of Didymos–Dimorphos, the paper argues that many small-binary secondaries may be relatively smooth “debris piles,” which would make the BYORP radiation torque systematically weaker and more size-dependent than assumed from lumpy asteroid shapes. A simple synthetic-shape experiment shows BYORP strength is controlled mainly by absolute surface relief (meter-scale roughness), implying larger secondaries should have smaller dimensionless BYORP coefficients and helping reconcile the wide range of observed orbital period drifts. The authors also interpret Dimorphos’s apparent post-impact reshaping (oblate to more prolate) as evidence that dissipation may occur in short, high-mobility episodes (e.g., impact-triggered landslides) rather than steady, long-term tidal damping. If correct, binary properties like low eccentricity and near-synchronous rotation may record recent dissipative events, and Hera can test whether Dimorphos continues to relax dynamically by 2026.
Their findings suggest that for relatively spheroidal bodies composed of small-scale debris, such as Dimorphos, the BYORP effect may be significantly weaker and more sensitive to the object's size than earlier models predicted.
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Wen-Han 文翰 Zhou 周, David Vokrouhlický, Masanori Kanamaru et al. · 2024 · The Astrophysical Journal Letters
Shows Yarkovsky forces can rapidly reshape binary-asteroid orbits, driving satellites toward synchrony or ejection on ~0.1 Myr timescales.
This paper elevates the often-neglected Yarkovsky force to a key driver of small binary-asteroid evolution, alongside tides and BYORP. It develops an analytic “binary Yarkovsky” model that combines eclipse-driven Yarkovsky–Schach (YS) forcing with a weaker, opposing planetary Yarkovsky term, and validates the scaling against thermophysical simulations. The main implication is a set of new evolutionary pathways: prograde asynchronous secondaries are pushed toward the synchronous-orbit location (often faster than tides and possibly competitive with stochastic YORP), while retrograde secondaries are driven outward, potentially creating asteroid pairs with opposite spin poles. The work also makes mission-testable predictions, including a potentially measurable post-DART orbital shrinkage rate for Dimorphos if it was knocked out of synchronous rotation, and suggests Yarkovsky-assisted synchronization for the wide Dinkinesh–Selam system where tides are too weak.
By developing and numerically verifying an analytical model that includes Yarkovsky–Schach and planetary thermal effects, the researchers demonstrated that the Yarkovsky force significantly impacts mutual binary orbits. This orbital evolution occurs specifically in non-synchronous systems, where the spin and orbital periods differ, opening up new possibilities for understanding how binary systems migrate over time.
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Alex J. Meyer, Daniel J. Scheeres · 2024
Contact binary mergers can occur between rubble piles if secondaries have modest cohesion (∼1–100 Pa) or high friction, shaped by lobe geometry.
This paper quantifies when a smaller lobe can survive tidal disruption while spiraling into and merging with a larger rubble-pile body to form a contact binary. Using ellipsoidal fits to 11 radar/spacecraft shape models (asteroids, comets, and Arrokoth), it derives strength requirements showing that either a small but nonzero cohesion or a sufficiently large friction angle is typically needed, with inferred cohesive strengths broadly ∼1–100 Pa for a nominal 30° friction angle. The analysis highlights strong dependence on secondary shape: prolate (cigar-like) lobes require substantially more cohesion than oblate (disk-like) lobes, and there are regime “flips” where how cohesion scales with size or density ratio changes near modest asphericities. By comparing contact binaries to binary asteroids and asteroid pairs, the authors argue contact binaries plausibly sit on related evolutionary pathways (e.g., collapsed binaries or failed separations) rather than requiring monolithic components.
This research examines how strong the material of 'contact binary' asteroids must be to allow them to fuse into a single object.
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Noam Segev, Eran O Ofek, David Polishook · 2022 · Monthly Notices of the Royal Astronomical Society
Models Gaia astrometric center-of-light wobble to search for unresolved binary asteroids and quantifies why DR2 yields few detections.
This paper develops and tests an astrometric approach to find unresolved binary asteroids by modeling how a system’s center of light wobbles around its center of mass. The key novelty is a forward model plus an inversion/search pipeline (with bootstrap-based false-positive estimation) tailored to Gaia’s along-scan astrometry and irregular sampling, aiming to probe binary parameter space that imaging, lightcurves, and radar miss. Using Gaia DR2 Solar System residuals, the authors find no strong new detections and argue this is largely because DR2’s processing clipped “outlier” transits that may contain genuine astrophysical wobble signals; nonetheless, known binaries show a small excess in astrometric scatter compared to the overall asteroid population. A case study of (4337) Arecibo yields only a marginal (∼2.2σ) period near half the DR3-reported value, underscoring both the promise and the current catalog limitations for astrometric binary discovery.
This study explores the detection of binary systems via the astrometric shift of the photocenter relative to the barycenter. By utilizing this "wobble," we can probe regions of the binary asteroid phase-space that remain challenging for standard observational techniques to reach.
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P. Pravec, P. Fatka, D. Vokrouhlický et al. · 2019 · Icarus
Survey of 93 asteroid pairs reveals widespread rotational-fission signatures, frequent paired binaries, and puzzling high–mass-ratio outliers.
Using a greatly expanded sample of 93 genetically related asteroid pairs, this work shows that most pairs obey the predicted link between primary spin rate and pair mass ratio, strengthening rotational fission as the dominant formation path. It also uncovers a surprisingly high incidence of binaries (and even triples) among the fastest-rotating primaries, implying that pair formation often involves more complex multi-body evolution than a simple two-body split. The paper highlights four secure, high–mass-ratio pairs that fall outside existing theory, and explores (but cannot yet physically justify) an extreme scenario where a flattened parent fissions and the components reshape to enable near-equal-mass escape. Overall, it reframes asteroid pairs as a diverse population that constrains YORP-driven fission, post-fission spin/orbit evolution, and the boundary between “pairs,” “clusters,” and “paired binaries.”
Authors derived and estimated many astrometric and physical parameters about 93 genetically connected asteroid pairs.
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C de la Fuente Marcos, R de la Fuente Marcos · 2018 · Monthly Notices of the Royal Astronomical Society: Letters
Two near-Earth asteroids form a long-lived “faux-binary” because both are trapped in Venus’s 3:5 mean-motion resonance.
This paper reports an unusually tight, dynamically coherent near-Earth asteroid pair (2017 SN16 and 2018 RY7) whose proximity persists far longer than typical NEA orbit randomization would allow. Using N-body integrations with uncertainty sampling, the authors show both objects are concurrently trapped in the 3:5 mean-motion resonance with Venus, which locks their average angular speeds and prevents secular drift in their relative mean longitude, creating a quasi-satellite-like (but non-gravitationally bound) configuration. Statistical comparison against the debiased NEOPOP steady-state model finds a significant overabundance of similar orbits relative to expectations, supporting a recent in situ origin rather than standard delivery pathways from the main belt. The most plausible formation scenarios are YORP-driven rotational fission or binary dissociation occurring while resonantly confined, suggesting resonances can preserve genetic links among NEAs long enough to be observed and tested (e.g., via spectroscopy).
They demonstrate that the Near-Earth Asteroids 2017 SN16 and 2018 RY7 currently follow an orbital path where their relative mean longitude remains stable. This lack of long-term drift is a direct result of the stabilizing influence of the 3:5 MMR with Venus.
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J.-L. Margot, P. Pravec, P. Taylor et al. · 2015 · Asteroids IV
A synthesis of evidence that small asteroid binaries, triples, and pairs mainly form via YORP-driven rotational fission, not impacts.
This review consolidates a decade of observations and dynamical theory showing that many small (≲20 km) asteroid systems—binaries, triples, and unbound pairs—share signatures of formation by rotational fission after YORP spin-up. It links radar, lightcurve, spectroscopy, imaging, and occultation results to a single evolutionary framework where post-fission dynamics, tides, and BYORP can yield the observed diversity of system architectures. In contrast, it argues that satellites of large (≳20 km) main-belt asteroids are best explained by collisional formation, based on their low mass ratios and angular momentum content. The synthesis matters because it elevates rotational disruption to a population-shaping process for small bodies and provides practical observational diagnostics (spin states, angular momentum, pole anisotropy, mass-ratio limits) to discriminate formation pathways.
Observational data confirms that binaries smaller than 20 km typically originate from rotational fission, a process driven by the YORP effect. This suggests a comprehensive framework where rotational fission and subsequent dynamical evolution account for the creation of small-scale binary, triple, and paired asteroid systems.
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Kevin J. Walsh, Derek C. Richardson, Patrick Michel · 2008 · Nature
Simulations show YORP spin-up can shed equatorial rubble that re-accretes into close, circular satellites matching small binary asteroids.
This paper identifies a single formation pathway that can explain why small binaries in both near-Earth and inner main-belt populations look so similar. Using rubble-pile simulations under gradual YORP-driven spin-up, the authors show that equatorial material is shed and, if collisions are sufficiently dissipative and the primary stays nearly axisymmetric, the debris efficiently accretes into a close satellite on a low-eccentricity orbit. The model naturally produces “top-shaped” primaries with equatorial ridges, consistent with detailed radar constraints for (66391) 1999 KW4, and predicts that secondaries are built mostly from the primary’s surface material. The work shifts small-binary origins away from impacts or repeated tidal encounters toward a slow, radiatively driven rotational-disruption cycle, with implications for surface refreshment and binary lifetimes via BYORP/tides.
While the origin of similar binaries (primary and satellite) in these two dynamically different populations (MB and NEA) was previously unknown, here is showed that they form via YORP-induced spin-up of 'rubble pile' asteroids.
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