Determination of Effective Temperatures and Surface Gravities from the Ultraviolet Spectral Flux Distribution


The determination of the stellar atmosphere parameters (i.e., effective temperature and surface gravity) is the first step to derive information on chemical abundances as well as to test, by a comparison of the theoretical and empirical HR diagrams, the consistency of the predictions based on theories of stellar structure and evolution with observations.

The possibility of achieving an accurate effective temperature and surface gravity determination by comparing the observed stellar flux distributions with those predicted by fully blanketed atmosphere models like ATLAS9 has been demostrated in the past by several authors (e.g.Malagnini et al. 1982) . An application of the method is shown below.

The sample

Spectral Type Object SIMBAD
B5 IV HD 147394 Info
A0 V HD 172167 (Vega) Info
A7 V  HD 187642 (Altair)  Info 
F5 IV-V  HD 61421 (Procyon)  Info 
G5 V  HD 20630  Info 
K2 V  HD 22049 (eps Eri)  Info 
K1.5 III  HD 124897 (Arcturus)  Info 

An animation showing the flux distribution of these stars can be found here

To see these stars as well as some other well-known objects on a Hertzprung-Russel diagram, click here


Back to the INES Demos page