Tidal disruption of NEAs - a case of Příbram meteorite

Abstract

This work studies the dynamical evolution of a possible meteor stream along the orbit of the Příbram meteorite, which originated in the tidal disruption of the putative rubble-pile-like parent body during a close approach to the Earth. We assumed the disruption at the time when the ascending or descending node of the parent orbit was close to the Earth's orbit. In the last 5000 yr, the Příbram orbit has crossed the Earth orbit twice. It happened about 4200 and 3300 yr ago. In both cases, we modelled the release of particles from the simplified model of rotating asteroid, and traced their individual orbital evolution to the current date. It takes several hundred years to spread released meteoroids along the entire orbit of the parent body. Even today, the stream would be relatively narrow.Considering a model parent body with physical parameters of the asteroid Itokawa, the complete disintegration of the object produced 3.8 × 10 11 meteoroid particles with diameter ≥1 cm. The meteor activity observed from the Earth is revealed and justification of follow-up observation during suggested activity of the shower in the first two weeks of April is discussed.The Earth's tidal forces would disintegrate a fraction of the New Earth Asteroid (NEA) population into smaller objects. We evaluate the upper limit of the mass of disintegrated asteroids within the mean NEA lifetime and the contribution of disrupted matter to the size distribution of the NEA.

Infrequent visitors of the Kozai kind: the dynamical lives of 2012 FC71, 2014 EK24, 2014 QD364, and 2014 UR

“…Walsh et al 2008) or tidal stresses (see e.g. Tóth et al 2011). These last three processes can easily produce secondary fragments.…”

Properties and evolution of NEO families created by tidal disruption at Earth

“…Mild tidal events might be also capable of producing meteoroid streams. The close passage of an object by a planet can lift material from the surface that then spreads along the object's orbit with time due to the small ∆v imparted by the lifting process and gravitational perturbations by other objects in the solar system (Kornoš et al 2009;Tóth et al 2011). After hundreds of years the particles will be distributed along the entire orbit and will produce meteors and fireballs if they enter Earth's atmosphere.…”

“…However, due to the single-event nature of the tidal disruption the stream would not be replenished and the putative meteoroid stream could only be observed for a short time after creation. Tóth et al (2011) calculated the maximum activity of a meteor shower originating from the putative Pribram meteorite progenitor to be only 1 meteor in 8 days visible from a single observing place. Richardson et al (1998) performed numerical simulations of NEO distortion and disruption by Earth's tides using more realistic asteroid shapes, spin rates, axis orientations, perigee distance q, relative speed at infinity v ∞ and body orientation at periapse, and identified four classes of tidal encounter outcomes (that should not be confused with the capital letters used to identify asteroid taxonomic classes): s) catastrophic disruptions in which the largest remaining fragment retains less than 50% of the parent's mass (similar to SL9), b) rotational breakup in which the largest remaining fragment retains 50%-90% of the parent's mass, m) mild disruption in which less than 10% of the parent's original mass is lost and, n) no mass loss but possible morphological modification.…”

“…An NEO with D > 1 km (H p 17.5) suffers an s-class event near Earth or Venus roughly every 3,200 years and some kind of disruption event (M-, Band s-class) occurs once about every 1,000 years (Richardson et al 1998). More recently Tóth et al (2011) calculated that the frequency of tidal disruptions of any kind for NEOs with D > 200 m (H p 21) is ∼ 1.6 × 10 −4 /year or roughly one tidal disruption every 6,200 years -within a factor of 2 of the Richardson et al (1998) disruption rate. Our eventual goal is to measure or set a limit on the disruption rate in an effort to distinguish between the two calculations and thereby test the entire NEO orbit and disruption modeling process.…”

Fragments of Late Eocene Earth-impacting asteroids linked to disturbance of asteroid belt

“…Its encounter with the gravity of the Earth-Moon system may have shed off substantial amounts of asteroid debris already at distances of 10,000-20,000 km from Earth. Asteroids entering within the Roche limit get affected by tidal gravity, and anything between loss of surface material to complete disruption of the asteroid may happen (Richardson et al, 1998;Nesvorný et al, 2010;Tóth et al, 2011;Schunova et al, 2014;Yu et al, 2014). Recent space missions to asteroids Itokawa and Eros (mean diameters 0.3 and 17 km, respectively) have shown that small to large asteroids have a significant layer of lose regolith or "rubble-pile" debris on their surface (Murdoch et al, 2013).…”