• Login
    View Item 
    •   Home
    • UA Graduate and Undergraduate Research
    • UA Theses and Dissertations
    • Dissertations
    • View Item
    •   Home
    • UA Graduate and Undergraduate Research
    • UA Theses and Dissertations
    • Dissertations
    • View Item
    JavaScript is disabled for your browser. Some features of this site may not work without it.

    Browse

    All of UA Campus RepositoryCommunitiesTitleAuthorsIssue DateSubmit DateSubjectsPublisherJournalThis CollectionTitleAuthorsIssue DateSubmit DateSubjectsPublisherJournal

    My Account

    LoginRegister

    About

    AboutUA Faculty PublicationsUA DissertationsUA Master's ThesesUA Honors ThesesUA PressUA YearbooksUA CatalogsUA Libraries

    Statistics

    Most Popular ItemsStatistics by CountryMost Popular Authors

    Part I: How Did We Get Here? College Students' Preinstructional Ideas on the Topic of Planet Formation, and the Development of the Planet Formation Concept Inventory; Part II: Evidence for Magnetically Driven Protoplanetary Disk Winds

    • CSV
    • RefMan
    • EndNote
    • BibTex
    • RefWorks
    Thumbnail
    Name:
    azu_etd_17254_sip1_m.pdf
    Size:
    3.098Mb
    Format:
    PDF
    Download
    Author
    Simon, Molly
    Issue Date
    2019
    Keywords
    Assessment
    Planet Formation
    Protoplanetary Disks
    Science Education
    Advisor
    Impey, Christopher D.
    Buxner, Sanlyn R.
    
    Metadata
    Show full item record
    Publisher
    The University of Arizona.
    Rights
    Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction, presentation (such as public display or performance) of protected items is prohibited except with permission of the author.
    Abstract
    This dissertation includes two independent research projects, one in astronomy education research and the other in planetary science/astrophysics research. In the first research effort, we investigate college students' conceptual and reasoning difficulties on the topic of planet formation pre-instruction. Through an analysis of over 1,000 responses to open-ended questions, we find that these students lack an understanding of fundamental topics in astronomy (e.g. gravity, basic definitions of a planet or solar system, mass versus density). The results from this analysis laid the foundation for the development of the Planet Formation Concept Inventory (PFCI), an educational research tool that can be used like a diagnostic test to assess students' pre- and post-instructional knowledge. Using iterative design and statistical processes consistent with Classical Test Theory (CTT), we are able to confirm that the PFCI is a reliable and valid instrument that can be utilized to measure college students' learning on the topic of planet formation over time. In the second research effort, we analyze forbidden lines (predominantly the [O I] line at 6300 Å) from a sample of 33 T-Tauri stars with disks spanning a range of evolutionary stages. After removing a high-velocity component (HVC) associated with microjets, we focus our efforts on studying the low-velocity component (LVC) to better elucidate its origin. The LVC can be attributed to slow disk winds that are either thermally or magnetically driven. We find that the LVC itself can be resolved into two distinct components: a broad component (FWHM > 40 km/s) and a narrow component (FWHM < 40 km/s). Additionally, we find that the FWHM of both components correlates with the disk inclination, consistent with Keplerian broadening from radii of 0.05 to 0.5 AU for the BC and 0.5 to 5 AU for the NC. Since the BC emission arises inward of 0.5 AU where the gravity of the star/disk system is strong, we eliminate the possibility that the BC traces a thermally-driven wind, and instead suggest that it traces the base of a magnetohydrodynamic (MHD) wind. For the NC, half of the features we observe have centroid velocities consistent with the stellar velocity, and the other half have blueshifts between -2 and -5 km/s. For this component of the LVC, the origin remains more elusive, and we cannot exclude the possibility that the NC arises in a photoevaporative wind.
    Type
    text
    Electronic Dissertation
    Degree Name
    Ph.D.
    Degree Level
    doctoral
    Degree Program
    Graduate College
    Planetary Sciences
    Degree Grantor
    University of Arizona
    Collections
    Dissertations

    entitlement

     
    The University of Arizona Libraries | 1510 E. University Blvd. | Tucson, AZ 85721-0055
    Tel 520-621-6442 | repository@u.library.arizona.edu
    DSpace software copyright © 2002-2017  DuraSpace
    Quick Guide | Contact Us | Send Feedback
    Open Repository is a service operated by 
    Atmire NV
     

    Export search results

    The export option will allow you to export the current search results of the entered query to a file. Different formats are available for download. To export the items, click on the button corresponding with the preferred download format.

    By default, clicking on the export buttons will result in a download of the allowed maximum amount of items.

    To select a subset of the search results, click "Selective Export" button and make a selection of the items you want to export. The amount of items that can be exported at once is similarly restricted as the full export.

    After making a selection, click one of the export format buttons. The amount of items that will be exported is indicated in the bubble next to export format.