Bibcode
Crivellari, L.; Praderie, F.
Referencia bibliográfica
Astronomy and Astrophysics, vol. 107, no. 1, Mar. 1982, p. 75-87. Research supported by the Consiglio Nazionale delle Ricerche.
Fecha de publicación:
3
1982
Revista
Número de citas
25
Número de citas referidas
22
Descripción
Observations of the 1400-1800 A region in late A type stars are
presented, which were obtained using the IUE satellite at low and high
resolution. The calibrated energy distribution is derived and presents a
large variation with wavelength in the spectral range due to Si I
photoionization discontinuities. Emission lines formed in the transition
region do not appear, although upper limits on the emission in these
lines are established. A schematic model is proposed for the outer
layers in A type stars, which suggests that the chromosphere in solar
type stars is likely absent in A stars, while the NLTE photosphere could
be immediately connected to the transition region, joining the upper
photosphere to the corona. In addition, the amount of matter in the
transition zone is found to be small.