Bibcode
Campins, Humberto; Morbidelli, A.; de León, J.; Tsiganis, K.; Licandro, J.
Bibliographical reference
American Astronomical Society, DPS meeting #42, #60.05; Bulletin of the American Astronomical Society, Vol. 42, p.1086
Advertised on:
10
2010
Citations
0
Refereed citations
0
Description
Near-Earth asteroid 101955 (1999 RQ36; henceforth RQ36) is particularly
interesting. It's especially accessible to spacecraft and is the primary
target of NASA's OSIRIS-REx sample return mission; it's also a
potentially hazardous asteroid (Milani et al. 2009). We combine
dynamical and spectral information to identify the most likely main-belt
origin of RQ36 and conclude that it is the Polana family, located at a
semi-major axis of about 2.42 AU (our approach is similar to that used
by de León et al. (2010) to link 3200 Phaethon, parent body of
the Geminids, to 2 Pallas).
Our conclusion is based on the following results. a) Dynamical evidence
favors strongly an inner-belt, low-inclination (2.15 AU < a < 2.5
AU and i < 10 degrees) origin, suggesting the ν6
resonance as the preferred (95% probability) delivery route. b) This
region is dominated by the Nysa and Polana families (families are
favored over single objects because small fragments have already been
produced). c) The Polana family is characterized by low albedos and
B-class spectra or colors (Bus and Binzel 2002), which is the same
spectral class, and albedo, as RQ36. d) The SDSS colors show that the
Polana family is the branch of the Nysa-Polana complex that extends
toward the ν6 resonance; furthermore, Polana has delivered
objects the size of RQ36 and larger into the ν6 resonance.
e) RQ36 is retrograde, consistent with the Yarkovsky effect having moved
it inward from Polana into the ν6. f) A quantitative
comparison of visible and near-infrared spectra does not yield a unique
match for RQ36; however, it is consistent with a compositional link
between RQ36 and the Polana family.
Finally, the Polana Family is likely the most important inner-belt
source of low albedo Near-Earth asteroids.
This work was supported by NASA and NSF.