Space Telescope Science Institute   3.4 Combining FGS Modes: Determining Stellar Masses  3.6 Relative Photometry

3.5 Angular Diameters


The FGS has been used (Lattanzi et al. 1997) to determine the angular diameters of non-point sources. The example given in Figure 3.5 shows the Transfer Function of a Mira-type variable superposed on the S-Curve of a point source (both observed with FGS3). The extended source - a disk of 78 mas - is clearly distinguishable from a point source. In addition to stellar discs, other objects which might be (or have been) resolved by the FGS include galactic nuclei, asteroids, and planetary moons.

Figure 3.5: Mira-type variable with a resolved circumstellar disk

 

 3.4 Combining FGS Modes: Determining Stellar Masses  3.6 Relative Photometry
Space Telescope Science Institute
http://www.stsci.edu
Voice: (410) 338-1082
help@stsci.edu