Bibcode
Delbo, Marco; Nesvorny, D.; Licandro, J.; Ali-Lagoa, V.
Bibliographical reference
American Astronomical Society, DPS meeting #44, #202.01
Advertised on:
10
2012
Citations
0
Refereed citations
0
Description
The Baptistina Asteroid Family (BAF) is the result of the breakup of an
asteroid roughly 100 million years ago. This family is the source of
meteoroids and near-Earth asteroids and likely caused an asteroid shower
of impactors on our Earth. Bottke et al. (2007) proposed a link between
the BAF and the K/T impactor, based on the favorable timing, large
probability of a terrestrial impact of one 10-km BAF asteroid, and the
Sloan colors of the BAF members, indicating that the BAF may have
composition consistent with the K/T impactor (CM2-type carbonaceous
meteorite, as inferred from chromium studies at different K/T boundary
sites; Alvarez et al. 1980, Kring et al. 2007). The relationship between
the BAF and K/T impactor is now controversial. Masiero et al. (2011)
found that the albedo of BAF family members is 0.15, significantly
higher than expected for a dark carbonaceous parent body. Also, Reddy et
al. (2011) reported the spectroscopic observations of (298) Baptistina
and objects in the general neighborhood of the BAF, and suggested the
BAF includes a mixture of spectroscopic types that is not very different
from the background (mostly S-type asteroids in the background Flora
family). Unfortunately, Reddy et al. observed only the large asteroids
near (298) Baptistina, and not the K/T-impactor-size BAF members with D
10 km. Using WISE albedos, Sloan colors and newly obtained
spectroscopic observations of BAF members, here we show that (1) the
large objects in the BAF are mostly BAF interlopers, (2) that BAF has an
homogeneous composition consistent with an X-type class. We discuss the
implications of the link between the BAF and the K/T impactor.