Abstract A summary of IUE results concerning late-type stars is presented. Observations show that high-temperature outer atmospheres, as indicated by N V, C IV emission at T ≈ 105K, are generally present only in high-gravity (log g ≳ 2) stars. Objects with high-temperature emission tend not to exhibit cool circumstellar shells, and vice versa, although there are several transition objects, the hybrid atmosphere stars, which combine C IV emission with cool winds. Ultraviolet emission from stellar transition regions correlates well with chromospheric and X-ray emission. Transition-region line ratios indicate that many stars have differential emission measure distributions similar to the Sun's. Ultraviolet observations also give indications of important dynamical effects in low-gravity stars. Density diagnostics indicate extended chromospheres for some red giants and supergiants. In addition, the large widths of lines of high temperature ions in several luminous stars indicate supersonic motions.


    Access

    Check access

    Check availability in my library

    Order at Subito €


    Export, share and cite



    Title :

    IUE observations of cool stars


    Contributors:

    Published in:

    Publication date :

    1982-01-01


    Size :

    9 pages




    Type of media :

    Article (Journal)


    Type of material :

    Electronic Resource


    Language :

    English



    Einstein observations of cool stars

    Stern, Robert A. | Elsevier | 1982


    Einstein observations of cool stars

    Stern, R. A. | NTRS | 1982


    Cool luminous stars

    Linsky, Jeffrey L. | Elsevier | 1982


    Cool luminous stars

    Linsky, J. L. | NTRS | 1982


    Temperatures of coronae of cool stars, derived from EXOSAT observations

    Mewe, R. / Lemen, J.R. / Schrijver, C.J. | Elsevier | 1989