• 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

    The low mass IMF in young open clusters.

    • CSV
    • RefMan
    • EndNote
    • BibTex
    • RefWorks
    Thumbnail
    Name:
    azu_td_9622985_sip1_m.pdf
    Size:
    3.289Mb
    Format:
    PDF
    Description:
    azu_td_9622985_sip1_m.pdf
    Download
    Author
    Williams, Douglas M.
    Issue Date
    1995
    Committee Chair
    Rieke, George
    
    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 or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.
    Abstract
    We present the results of the investigation of the Initial Mass Function at the end of the Main Sequence in young open clusters. We find that over a large range in age and environment the IMFs are similar to each other, and to recent determinations of the field star IMF. We have obtained V, I, and K band photometry of fields in the three relatively unembedded open clusters. The photometry reaches down to various masses in ech cluster: 0.08Mʘ for Praesepe, 0.04Mʘ for the Pleiades, and 0.15Mʘ for NGC 7160. We compare the methods for estimating the masses of young, embedded stars developed by Comeron et al. (1993) and by Strom et al. (1995) and show them to be in good agreement. Spectra in the 2 11m region of six low mass objects from Comeron et al. (1993) are also in agreement with the mass estimates using these methods. The spectrum of a brown dwarf candidate is used to place an upper limit on its mass of 60% of the minimum required for hydrogen burning. The IMFs from these four clusters plus NGC 2024 (Cameron et al. (1995)) are shown to be in agreement with each other. The composite MF can be fitted with a power law between 0.04 and 0.5Mʘ with a slope of -0.75 ± 0.3. There is no evidence for a cutoff at the bottom of the main sequence (0.08Mʘ); brown dwarfs appear to be abundant in open clusters. However, the slope of the MF is well above the value of ≲ -2 required for very low mass stars and brown dwarfs to contribute a significant portion of the mass of open clusters. The composite cluster MF also is in agreement with recent determinations of the field star IMF for stellar masses. The field star data do not extend into the brown dwarf range; however, if we extrapolate in accordance with the cluster MF, we conclude that brown dwarfs probably do not contribute significantly to the dark matter.
    Type
    text
    Dissertation-Reproduction (electronic)
    Degree Name
    Ph.D.
    Degree Level
    doctoral
    Degree Program
    Astronomy
    Graduate College
    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.