Fundamental Stellar Properties
What are Fundamental Stellar Properties?
Some research in the IoA is aimed at determining basic (and hard to measure) parameters of stars - mass, distance, separation,... - and detailed structure of stars.
Current research areas
Stellar Properties from Optical Interferometry
The Sydney University Stellar Interferometer (SUSI) measures the angular diameters of stars and the angular separations of binary systems. As a result it can determine a variety of fundamental properties of different classes of stars, for example:
- Single stars - measuring emergent fluxes, effective temperatures, radii and luminosities.
- Binary stars - as for single stars, plus measuring distances and masses.
- Variable stars (e.g. Cepheids and Miras) - as for single stars, plus distances.
- Emission line stars (e.g. Be and Wolf-Rayet stars) - measure the relative sizes of star and emission regions, emergent fluxes, effective temperatures.
and for various stars
- Stellar rotation.
- Limb darkening.
SUSI seen from the north end of the 640m baseline.
Interior structure of stars
Stellar oscillations depend on the physical properties of the stellar interior like density, temperature and composition. By measuring frequencies from many different oscillation modes we can reconstruct the sound speed profile of the star to learn about physical properties that we otherwise cannot measure. For more information see Stellar Oscillations