Abstract
view Abstract Citations (21) References (42) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Upper photospheric temperature models of K giants: a comparison of super-metal-rich giants with normal giants. Desikachary, K. ; Gray, D. F. Abstract The LTE version of K-line synthesis that takes partial coherency effects into account is applied to the Ca II K-line wings in the spectra of four normal K giants (Beta Gem, Nu Cyg, Rho Oph, Alpha Ari) and two super-metal-rich (SMR) K giants (Alpha Ser, Beta Oph) in order to derive upper-photospheric temperature models. A model-atmosphere flux-calibration procedure that precludes the necessity of a measured angular diameter is used in the analysis of the K-line wing profiles, on the basis of which the SMR and normal K giants are compared quantitatively. The results show that temperature enhancements of 200 to 300 K in excess of radiative-equilibrium models are required in the upper photospheres of all six stars and that the upper photospheres of the SMR star models are up to 180 K cooler than those of the normal models. The temperature enhancements are interpreted as departures from radiative equilibrium, and the differential cooling in the SMR stars is tentatively attributed to enhanced CN and CO line absorption. Publication: The Astrophysical Journal Pub Date: December 1978 DOI: 10.1086/156672 Bibcode: 1978ApJ...226..907D Keywords: Giant Stars; K Lines; K Stars; Metallic Stars; Photosphere; Stellar Models; Stellar Temperature; Calcium; Stellar Spectrophotometry; Thermodynamic Equilibrium; Astrophysics; Atmospheres:K Giants; K Giants:Line Profiles; K Giants:Metal-Rich Stars; Stellar Atmospheres: Models full text sources ADS | data products SIMBAD (7) Related Materials (1) Erratum: 1980ApJ...236.1056D
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