The Far Ultraviolet SpectroPolarimeter (FUSP)


FUSP is a sounding rocket payload that will obtain the first high-precision spectropolarimetry from 1050 - 1500 Angstroms, and the first astronomical polarimetry of any kind below 1300 Angstroms. It will provide measurements of polarization produced by electron scattering, resonance line scattering, and hydrogen Rayleigh scattering in the inner circumstellar environment of hot stellar systems, and thereby quantitatively constrain the geometry and dynamics of the system. In addition, the strength and geometry of the magnetic field will be determined from a new diagnostic tool, the Hanle Effect.

The Figure illustrates the FUSP optical design. The telescope is F/2.5 prime-focus with a 50 cm primary. At the telescope focus is the polarimetric optics, a stressed lithium flouride rotating waveplate, followed by a CVD diamond Brewster-angle mirror. The spectrometer uses an aberration-corrected spherical holographic grating and a UV-sensitized CCD detector. The spectral coverage is 1050 -1500 Ang, and the spectral resolution is 0.65 Ang, (R=1800) and the net spatial resolution is about 1 arcmin perpendicular to the dispersion.

FUSP Targets
Program Target V m133 Comment
Unpol Beta Tau 1.7 -0.5
Be Gamma Cas 2.5 -1.6 No shell lines
Zeta Tau 3.0 -0.3 Shell, WUPPE obs
Oe Xi Per 4.0 1.0 O7e rapid rotator
HD93521 7.1 2.8 O9e rapid rotator
WR EZCMa 6.9 2.5 WN5, WUPPE obs
SG Beta Ori 0.1 -0.8
Zeta Ori 2.1 -2.5 Magnetic Field Probe
Bin Beta Lyr 3.5 2.0 FUV all scattered?
ISM Sigma Sco 2.9 -0.5 Lambda(max)=560 nm
Rho Oph 5.0 2.1 Lambda(max)=680 nm

The first flight of FUSP is scheduled for late 2009, targeting Beta and Zeta Tau. If you can think of other targets we should add to our list, please let us know!

FUSP People

The Principal Investigator is Ken Nordsieck. The Instrument Scientist was Michael Westphall. Other folks who are or have been involved in various ways include (in alphabetical order) Joe Cassinelli, Dave Hoffman, Sam Gabelt, Jay Gallagher, Walt Harris, Rico Ignace, Kurt Jaehnig, Don Michalski, Jeff Percival,and Dick Pfeifer. The project is operated through the UW-Madison Space Astronomy Laboratory.

FUSP is supported by NASA grant NNX07AO81G.