High resolution profiles in A-type stars. III - VEGA C II and SI II UV lines observed with the Copernicus satellite

Details High resolution profiles in A-type stars. III - VEGA C II and SI II UV lines observed with the Copernicus satellite High resolution profiles in A-type stars. III - VEGA C II and SI II UV lines observed with the Copernicus satellite

Sep 1979

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1979a%26a....78..148f&link_type=abstract

Astronomy and Astrophysics, vol. 78, no. 2, Sept. 1979, p. 148-158.

Statistics

Computation

19

A Stars, Atmospheric Models, Oao 3, Spectrum Analysis, Stellar Atmospheres, Ultraviolet Spectra, Chromosphere, Computation, High Resolution, Observation, Spectral Resolution, Stellar Rotation, Stellar Temperature, Thermodynamic Equilibrium

Scientific paper

High-resolution (50-mA) Copernicus UV spectra are used in a study of the external atmospheric layers of Vega (Alpha Lyrae, A0 V) based on a modification of model atmospheres to allow temperature rises and an attempt to reproduce the observations with the models. Profiles of the UV resonance multiplet of C II at approximately 1335 A are analyzed along with profiles of the Si II lines at about 1304 and 1309 A. Radiative-equilibrium (RE) LTE, RE non-LTE, and non-LTE model atmospheres with different chromospheric temperature rises are employed in the analysis. A non-LTE line computation is found to yield acceptable agreement between the theoretical and observed line profiles with the model of Schild et al. (1971), Frandsen's (1974) model, and type 1 chromospheres. It is concluded that although the observed line cores do not exhibit any emission or shoulders, a chromospheric temperature rise may occur at a 5000-A optical depth of 0.0001 in early A-type stars.

Affiliated with

Also associated with

No associations

Rating

High resolution profiles in A-type stars. III - VEGA C II and SI II UV lines observed with the Copernicus satellite does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with High resolution profiles in A-type stars. III - VEGA C II and SI II UV lines observed with the Copernicus satellite, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and High resolution profiles in A-type stars. III - VEGA C II and SI II UV lines observed with the Copernicus satellite will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-1817270