Located at the edge of the observable solar system, the Kuiper belt contains ~70,000 objects larger than 100 km in diameter. Over 800 of these small, icy bodies have been identified and catalogued. The inhabitants of this region (Kuiper belt objects, aka KBOs) have likely experienced little thermal modification since their formation 4.5 billion years ago, so the Kuiper belt may be considered a fossil record of the outer solar system. In its youth, the Kuiper belt might have appeared from afar as a disk of debris, analogous to the those currently observed around young stars (e.g. Beta Pictoris), providing a link between our knowledge of processes at work in our solar system to those at work in stellar disks in the early stages of their evolution. Dr. James Elliot and colleagues will pursue an integrated set of four research tasks to investigate the Kuiper belt, primarily with the 6.5-m Magellan telescopes at Las Campanas Observatory: (1) complete a discovery sample of 500 KBOs through our participation in the Deep Ecliptic Survey (DES), (2) attempt to identify a primordial population at the center of the Kuiper belt plane with multi-color observations, (3) discover and characterize the binary KBOs, and (4) refine orbits for a set of KBOs to the level required to predict stellar occultations.
The goal of the DES is to discover 500 KBOs and to follow up the discoveries until the objects have orbits that are sufficiently accurate for dynamical classification. This survey provides a well-documented sample of KBOs from which inferences can be made about the entire KBO population. Dr. Elliot and team will recover southern-hemisphere DES discoveries with the Magellan telescopes. Recovery observations will prevent the loss of new discoveries, establish dynamical classes, and identify particularly interesting objects, such as binary KBOs. Data from the DES demonstrates that the distribution of KBOs as a function of latitude relative to the plane of the Kuiper belt is sharply peaked. Such an unresolved peak suggests a dynamically primordial population of KBOs. The second research task is to obtain photometry of these KBOs with the Magellan telescopes to compare with the average Kuiper belt population. These observations may uncover a physical difference in the KBOs that have not experienced major orbital perturbations since their formation. Binary KBOs are of interest because the system mass can be deduced from knowledge of a binary orbit, and their existence and collective properties constrain dynamical models of the Kuiper belt. This project will characterize their shapes and albedos with photometric observations. With stellar occultations, Dr. Elliot can probe KBOs with a spatial resolution of a few kilometers, and from these data can establish their diameters, probe for an atmospheres, and search for potential nearby companions. He plans to improve the orbit quality of the brightest KBOs in the southern hemisphere to the accuracy needed to predict occultations.
The research will not only further our knowledge of the Kuiper belt, but it will have broader impacts as well. It will contribute to the education of undergraduates, graduate students, and postdoctoral associates through their involvement in the research. This research program will also foster broader community interactions through strong connections to the DES team (six institutions) and the Magellan consortium (five institutions). The results will be disseminated to the community and the public at large through the worldwide web, talks, and publications. ***
