The Baptistina family is an asteroid family that was likely produced by the breakup of an asteroid
170 km (110 miles) across 160 million years ago following an impact
with a smaller body. The largest presumed remnant of this parent
asteroid is 298 Baptistina. Many mountain-sized fragments from the collision would have leaked into the inner solar system through orbital resonances with Mars and Jupiter,
causing a prolonged series of asteroid impacts between 100 and 50
million years ago. The Baptistina "family" may consist of uncommon carbonaceous chondrite asteroids and meteoroids in similar orbits. Chromium concentrations in 65-million-year-old sediment layers at the Kâ€“T boundary on Earth suggest that the impactor that gouged out Chicxulub Crater belonged to this group.
Concerns have been raised regarding the reputed link, in part because
very few solid observational constraints exist of the asteroid or
family. Indeed, it was recently discovered that 298 Baptistina does not share the same chemical signature as the source of the K-T impact.
Although this finding may make the link between the Baptistina family
and K-T impactor more difficult to substantiate, it does not preclude
the possibility. It has been speculated that the impactor that produced the lunar crater Tycho 108 million years ago was also a member of the group.