Back to Volume
Paper: Science Capabilities of the ST3 Mission
Volume: 194, Working on the Fringe: Optical and IR Interferometry from Ground and Space
Page: 224
Authors: Linfield, R. P.; Gorham, P. W.
Abstract: The ST3 mission will perform visible wavelength (450-900 nm) interferometry on baselines of 40 m-200 m, using two spacecraft in heliocentric orbit. Launch is scheduled for 2003. The design capability is a detection limit of mv = 8 for a stellar visibility of 0.3, with fainter limits for less resolved stars. Approximately 100 stars can be observed during the nominal 4-5month interferometry phase of the mission. Science targets of interest include Wolf-Rayet stars, Be stars, and M dwarfs. For Wolf-Rayet stars, the compact continuum emission can be used for fringe tracking and as a phase reference. This will allow low amplitude complex visibilities to be measured in several of the strong, broad emission lines, providing an image of the outflow. The stellar continuum can also be used for fringe tracking with Be stars. By operating the instrument in a Fourier Transform Spectrometer mode, a velocity resolution of 50-100 km/s should be possible. This will allow the Be star circumstellar disks to be resolved both spatially and in velocity. Angular size measurements of M dwarfs (as late as M6-M7) will allow a determination of their effective temperatures, which are now poorly known. A visibility calibration accuracy of Δ Γ = 0.02 will allow effective temperature measurements to ~5%.
Back to Volume