Edinburgh Research Archive logo

Edinburgh Research Archive

University of Edinburgh homecrest
View Item 
  •   ERA Home
  • Physics, School of
  • Physics thesis and dissertation collection
  • View Item
  •   ERA Home
  • Physics, School of
  • Physics thesis and dissertation collection
  • View Item
  • Login
JavaScript is disabled for your browser. Some features of this site may not work without it.

A photographic survey of very low mass stars and brown dwarfs

View/Open
ThackrahAD_1996redux.pdf (21.22Mb)
Date
1997
Author
Thackrah, Andrew David
Metadata
Show full item record
Abstract
 
 
This thesis has taken the detection o f very low mass stars and brow n dwarfs by photographic methods as its theme. The case for the existence of brown dwarfs has been reviewed and it is concluded that current theories of the formation of low mass bodies in the inter-stellar medium are not sufficiently developed yet to able to place a lower limit to the minimum stellar fragmentation mass. Existing models consider the formation of binary and planetary systems as being more likely than the formation of free-floating objects. Models of stellar structure are more fully developed and suggest a continuation of the properties of low mass stars through a transitionary region near the minimum hydrogen burning mass down to objects with masses at least as small as 0.01M⨀. The weakest facet of the numerical models are the atmospheres which are essential for the relation of physical values to observable values. A seemingly systematic offset of 100-200K exists between model atmospheres and observations of the coolest stars although progress is being made in modelling the atmospheres of bluer, low metallicity stars where the effects of TiO and VO are less dominant.
 
To conclude, recent technical advances in measuring machine speed and accuracy and in plate and film material provide new opportunities to the stately art of photographic survey science. With recently reported detections of very convincing brown dwarf candidates in the Pleiades, the goals of this field of study have moved away from the singular issue of detecting sub-stellar objects and towards a quantification of their place as a population in the Milky Way and this is a task to which modern wide-field photographic techniques are well suited.
 
URI
http://hdl.handle.net/1842/27522
Collections
  • Physics thesis and dissertation collection

Library & University Collections HomeUniversity of Edinburgh Information Services Home
Privacy & Cookies | Takedown Policy | Accessibility | Contact
Privacy & Cookies
Takedown Policy
Accessibility
Contact
feed RSS Feeds

RSS Feed not available for this page

 

 

All of ERACommunities & CollectionsBy Issue DateAuthorsTitlesSubjectsPublication TypeSponsorSupervisorsThis CollectionBy Issue DateAuthorsTitlesSubjectsPublication TypeSponsorSupervisors
LoginRegister

Library & University Collections HomeUniversity of Edinburgh Information Services Home
Privacy & Cookies | Takedown Policy | Accessibility | Contact
Privacy & Cookies
Takedown Policy
Accessibility
Contact
feed RSS Feeds

RSS Feed not available for this page