Interstellar polarization at high galactic latitudes from distant stars. II. Evidence for depolarization starting at Z=~600pc.
We have measured linear polarization for 20 distant high latitude A and F stars, as a first step to extend our previous study (Berdyugin et al. 1995A&A...294..568B: Paper I) of the North Galactic polar cap to distances larger than 600pc. The results give tentative evidence for depolarization starting to be seen around Z=~500pc, possibly indicating that there is a significant change in the magnetic field direction. Depolarization requires that there is still light-polarizing dust in the Z range 500-1000pc and the lower limit to extinction inferred in Paper I (A_B_>0.11mag) must be increased by a yet undetermined amount.
Astronomy and Astrophysics
- Pub Date:
- February 1997
- SOLAR NEIGHBOURHOOD