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Since Protostars and Planets VI (PPVI), our knowledge of the global properties of protoplanetary and debris disks, as well as of young stars, has dramatically improved. At the time of PPVI, mm-observations and optical to near-infrared spectroscopic surveys were largely limited to the Taurus star-forming region, especially of its most massive disk and stellar population. Now, near-complete surveys of multiple star-forming regions cover both spectroscopy of young stars and mm interferometry of their protoplanetary disks. This provides an unprecedented statistical sample of stellar masses and mass accretion rates, as well as disk masses and radii, for almost 1000 young stellar objects within 300 pc from us, while also sampling different evolutionary stages, ages, and environments. At the same time, surveys of debris disks are revealing the bulk properties of this class of more evolved objects. This chapter reviews the statistics of these measured global star and disk properties and discusses their constraints on theoretical models describing global disk evolution. Our comparisons of observations to theoretical model predictions extends beyond the traditional viscous evolution framework to include analytical descriptions of magnetic wind effects. Finally, we discuss how recent observational results can provide a framework for models of planet population synthesis andmore »planet formation.« less

Principal investigators and project teams funded by the National Science Foundation are familiar with the requirement to discuss the impact of their research. Whether the discussion appears in a new proposal, or as part of annual or final reporting, describing the impacts of a project is key to demonstrating the value of the work itself. PIs and project teams may not, however, consider the ways in which their reporting on impacts can help them disseminate their work to stakeholders and propagate their innovations to other researchers. Impact statements can also be useful to NSF program officers who are often in the position of informing about and advocating for the projects under their management. Consequently, our work to support the NSF Revolutionizing Engineering Departments (RED) program helps project teams develop more coherent and persuasive impact statements. These impact statements lay the foundation for teams to persuasively disseminate their work. As part of our work to support the NSF Revolutionizing Engineering Departments (RED) program, we have developed an impacts tutorial that helps proposal and report writers capture what is impactful about their projects and to communicate that impact to multiple audiences (e.g., the NSF program officer, stakeholders for the project, etc.). Wemore »piloted the tutorial during the 2019 RED Consortium Meeting to the 21 RED teams in attendance. The tutorial began with a clear statement of the purpose of impact statements generally that was included in a printed workbook distributed to all attendees. From that starting point, groups made up of representatives from different RED teams worked to draft responses to the NSF Annual Report question prompts that address impacts. Initial feedback from NSF about this session have been positive and indicate improvements in reporting by RED teams. During our poster presentation at ASEE, we will introduce this method of writing impact statements, share elements of the workbook, and help attendees apply the method to their own NSF reporting.« less

We performed a comprehensive demographic study of the CO extent relative to dust of the disk population in the Lupus clouds in order to find indications of dust evolution and possible correlations with other disk properties. We increased the number of disks of the region with measured R CO and R dust from observations with the Atacama Large Millimeter/submillimeter Array to 42, based on the gas emission in the 12 CO J = 2−1 rotational transition and large dust grains emission at ~0.89 mm. The CO integrated emission map is modeled with an elliptical Gaussian or Nuker function, depending on the quantified residuals; the continuum is fit to a Nuker profile from interferometric modeling. The CO and dust sizes, namely the radii enclosing a certain fraction of the respective total flux (e.g., R 68% ), are inferred from the modeling. The CO emission is more extended than the dust continuum, with a R 68% CO / R 68% dust median value of 2.5, for the entire population and for a subsample with high completeness. Six disks, around 15% of the Lupus disk population, have a size ratio above 4. Based on thermo-chemical modeling, this value can only be explained ifmore »the disk has undergone grain growth and radial drift. These disks do not have unusual properties, and their properties spread across the population’s ranges of stellar mass ( M ⋆ ), disk mass ( M disk ), CO and dust sizes ( R CO , R dust ), and mass accretion of the entire population. We searched for correlations between the size ratio and M ⋆ , M disk , R CO , and R dust : only a weak monotonic anticorrelation with the R dust is found, which would imply that dust evolution is more prominent in more compact dusty disks. The lack of strong correlations is remarkable: the sample covers a wide range of stellar and disk properties, and the majority of the disks have very similar size ratios. This result suggests that the bulk of the disk population may behave alike and be in a similar evolutionary stage, independent of the stellar and disk properties. These results should be further investigated, since the optical depth difference between CO and dust continuum might play a major role in the observed size ratios of the population. Lastly, we find a monotonic correlation between the CO flux and the CO size. The results for the majority of the disks are consistent with optically thick emission and an average CO temperature of around 30 K; however, the exact value of the temperature is difficult to constrain.« less

Abstract: Honors education values diversity, not simply to enrich our classrooms but for equity and social justice. At Columbus State University, students of color were underrepresented in honors education, and we sought to determine if institutional structures hindered them from being able to access educational programming that was commensurate with their ability. We used focus group interviews with students of color who were academically eligible to enroll in honors education yet never participated. We combined focus group interviews with an analysis of our recruiting practices. Using a theoretical framework based on intersectionality and possible selves theory, we found that our participants valued diverse learning environments, balance, and co-curricular engagement that supported their professional, hoped-for selves. However, they perceived honors students as stressed, studious, and lacking leisure time, and they perceived honors education as disconnected from their future professional selves. Since their perceptions, which were informed by participation in advanced programs in middle school and high school, as well as our recruiting practices, were in conflict with their educational aims, our participants were unwilling to invest in honors education. While not generalizable, the results provide unique insights that may implicate institutional practices as barriers to participation because they fail to addressmore »the concerns of high-achieving students of color.« less