IUE ultraviolet spectra and chromospheric models of HR 1099 and UX ARIETIS
1980; IOP Publishing; Volume: 241; Linguagem: Inglês
10.1086/158386
ISSN1538-4357
Autores Tópico(s)Astronomical Observations and Instrumentation
Resumoview Abstract Citations (75) References (46) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS IUE ultraviolet spectra and chromospheric models of HR 1099 and UX Ari. Simon, T. ; Linsky, J. L. Abstract IUE spectra in the region 1150-3200 A of the RS CVn-type variables HR 1099 and UX Arietis are presented and analyzed in terms of chromospheric models. Measurements of Mg h and k lines and Ca II H-K and H alpha spectra are indicated which are found not to be correlated with orbital phase or radio flares and which suggest that the strong emission arises in the K star rather than the G star in these systems. Under the assumption that the UV emission lines are associated with the K star, surface gravities of log g = 3.6 and 3.4 and effective temperatures of 4850 and 5000 K are adopted for HR 1099 and UX Ari, respectively, along with solar metal abundances for each. Model calculations of the chromospheric structure necessary to account for observed C(+), Mg(+), Si(+) and Si(+2) line fluxes are presented which indicate that the transition region pressure lies in the range 0.18-1.0 dynes/sq cm, implying transition regions that are more extended than that of the sun and are not conductively heated. It is noted that pressure scaling laws and the use of Mg II and C II lines as pressure diagnostics may be invalid, possibly due to atmospheric inhomogeneities or gas flows. Publication: The Astrophysical Journal Pub Date: October 1980 DOI: 10.1086/158386 Bibcode: 1980ApJ...241..759S Keywords: Atmospheric Models; Chromosphere; K Stars; Stellar Atmospheres; Stellar Models; Stellar Spectra; Ultraviolet Spectra; Binary Stars; H Alpha Line; Iue; K Lines; Late Stars; Spaceborne Astronomy; Spectrum Analysis; Astrophysics full text sources ADS | data products SIMBAD (2) MAST (1) INES (1)
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