White Light Sunspot Observations from the Solar Optical Universal Polarimeter on Spacelab-2
Abstract
The flight of the Solar Optical Universal Polarimeter on Spacelab-2 provided the opportunity for the collection of time sequences of diffraction-limited (0.5 arc second) solar images with excellent pointing stability (0.003 arc second) and with freedom from the distortion that plagues ground-based images. A series of white-light images of active region 4682 were obtained on 5 August 1985, and the area containing the sunspot has been analyzed. These data have been digitally processed to remove noise and to separate waves from low-velocity material motions. The results include (i) proper motion measurements of a radial outflow in the photospheric granulation pattern just outside the penumbra; (ii) discovery of occasional bright structures (``streakers'') that appear to be ejected outward from the penumbra; (iii) broad dark ``clouds'' moving outward in the penumbra, in addition to the well-known bright penumbral grains moving inward; (iv) apparent extensions and contractions of penumbral filaments over the photosphere; and (v) observation of a faint bubble or looplike structure that seems to expand from two bright penumbral filaments into the photosphere.
- Publication:
-
Science
- Pub Date:
- November 1987
- DOI:
- 10.1126/science.238.4831.1264
- Bibcode:
- 1987Sci...238.1264S
- Keywords:
-
- Image Analysis;
- Polarimeters;
- Solar Instruments;
- Spacelab Payloads;
- Sunspots;
- Image Resolution;
- Photosphere;
- Satellite-Borne Instruments;
- Temporal Distribution;
- Solar Physics