p-p and p-t final state interactions in the reaction 3He(d, tp)p

Binary Minor Planets

“…There are significant selection effects involved in lightcurve observations. To date, observed secondary bodies all have D s 0.18 D p (Pravec et al 2005b). A smaller secondary may not have an observable signal above the noise of the primary period.…”

“…Soon afterward, several more AO binary MBAs were announced. In the meantime, lightcurve techniques revealed possible binary asteroids in the NEA HST: Hubble Space Telescope population (see Pravec et al 2005b for the latest compilation), many of which have now been confirmed by radar. Also during this time, detailed analytical and numerical techniques began to be applied to the problem of the origin and evolution of binary asteroids: Hamilton & Burns (1991), Chauvineau et al (1993), and Scheeres (1994) (for example) studied the dynamics and stability of binary orbits; Durda (1996) and Doressoundiram et al (1997) used computer simulations to show that asteroid impacts could generate orbiting companions similar to Ida's Dactyl; and Bottke & Melosh (1996a,b) showed that doublet craters on Earth and Venus could be explained by a ∼15% binary NEA population.…”

“…(An eclipse occurs when one component of the BMP casts a shadow on the other that can be seen by the observer; an occultation occurs when one component passes directly behind the other as seen by the observer.) Mutual events in the midst of a two-period lightcurve have largely convinced the community of the robustness of binary NEA detections using this technique (see Pravec et al 2005b for a summary of observations to date). Recent detections have also been made of fully synchronized systems, for which P p = P = P s .…”

“…Favorable geometry is also needed as eclipses/occultations require either the Sun or Earth to lie close to the binary orbital plane. The selection effects are well understood and when modeled have helped constrain distributions of properties for binary systems (Pravec et al 2005b).…”

“…Optimally, for a nearby BMP, radar can reveal more/better information about a binary than any of the other techniques, including the component sizes/shapes, spin periods, orbital parameters/total mass (indirectly via orbit fitting to range and Doppler data), and mass ratio (from reflex motion with respect to the center of mass). The technique was first used successfully on 2000 DP 107 (Margot et al 2002), a binary NEA that has also been examined by lightcurve (see Pravec et al 2005b and references therein); radar served as a validation of the lightcurve analysis. In fact, because it is not possible to unambiguously determine the orbit plane of a binary without multiple viewing angles and/or occultations/eclipses, combining radar data with lightcurve data is yielding the best orbits, particularly for binary NEAs.…”