Double or Nothing

Figure 1: He wrote the book A Fortunate Encounter During the poster session at #LPSC2017, I was surprised and delighted that Jay Melosh stopped to discuss my poster on doublet craters .  Not only had I cited some of his papers in my work, but he also "wrote the book" on Impact Cratering (no, really !). Dr. Melosh was genuinely interested, and also pleased to see that my co-author (and graduate advisor) was Ron Fevig , a former student of his at the Lunar and Planetary Laboratory at U of A. After examining the images of potential doublets from my survey area, Figure 2: Doublet crater on Ceres he noted that the ones I had identified as "highly eroded" (see figure 2) may not be that eroded, but were possibly secondary craters, since their rims were irregular rather than cleanly circular.  He also referred me to his book for a good description. Refining Crater Identification Criteria Moving into the next phase of my research, I need to be capable of ...

A doublet crater is a pair of impact craters in proximity to one another that are created by the same primary impact event. Doublet craters have been observed on Earth, on the Moon, on Mercury, on Venus, and on Mars. Doublet crater on Ceres. Dawn image FC0054639 ( NASA ) Doublet crater formation. Early research attributed doublet crater formation to a single impactor broken up by either atmospheric disruption or tidal forces, but further analysis revealed that these processes could not result in sufficient separation of the components to create observed doublets. It is now believed that well-separated binary asteroids are the true source of doublet craters. The percentage of impact craters in the inner solar system that are doublets would require ~15% of planet-crossing asteroids to be binaries. This makes doublets an excellent source of evidence for the prevalence of binary asteroidal systems, and can constrain the possible nature and formation processes for such binaries....