Forming Binary Near-Earth Asteroids From Tidal Disruptions

of the system mass M by way of Kepler’s Third Law,P 2 = 4π 2 a 3 /GM (1.1)with period P and mean separation a typically directly measured, and G is the gravitationalconstant. In most situations component sizes and shapes can be modeled allowingfor a rare measurement of asteroid density. When coupled with a spectroscopic estimateof asteroidal composition, estimates on porosity and internal structure can be made.The dynamical mechanisms affecting various populations of small bodies can also bestudied by way of binary asteroids. Binaries have been discovered in nearly every dynamicalpopulation of minor planets, with large numbers among trans-Neptunian objects (orKuiper Belt Objects), one binary Jovian Trojan, two binary Centaurs, and a plethora ofbinary Main Belt and near-Earth asteroids. Adding to this inventory are recent discoveriesof complex systems such as the additional satellites of Pluto, a triple KBO 2003 EL 61 ,and a triple Main-Belt asteroid (MBA) system (87) Sylvia. Since each population boastsdramatically different dynamical, collisional and thermal environments, the existence anddetailed study of binaries will be quite valuable.1.1.2 Binary near-Earth asteroidsThe known binary near-Earth asteroids (NEAs) have been discovered from a combinationof lightcurve and radar observations. Lightcurve studies, where an asteroid’s magnitudeis plotted over time, have been conducted on a large number of bodies. However, certainorbital properties (asynchronous orbit and favorable geometry) are needed to make anunambiguous assessment of the state of the binary (Weidenschilling et al. 1989; Pravec& Hahn 1997). The secondaries must be large enough (∼20% of the primary) for theirnonsynchronous periods to be observed above any noise in the lightcurve of the primaries.Observations must also capture occultations/eclipses over multiple revolutions of the sec-2