Heliospheric Latitude Variations of Properties of Cometary Plasma Tails: A Test of the Ulysses Comet Watch Paradigm
✍ Scribed by John C. Brandt; Martin Snow
- Publisher
- Elsevier Science
- Year
- 2000
- Tongue
- English
- Weight
- 472 KB
- Volume
- 148
- Category
- Article
- ISSN
- 0019-1035
No coin nor oath required. For personal study only.
✦ Synopsis
Images of comets de
Vico in 1995, Hyakutake in 1996, and Hale-Bopp in 1997 taken by observers in the Ulysses Comet Watch clearly show plasma tail properties reflecting the demarcation of the solar wind into distinct equatorial and polar regions with the boundary determined by the maximum extent of the heliospheric current sheet (HCS). Generally, (1) comet plasma tails in the polar region appear relatively undisturbed (as expected from a steady solar wind), while comet tails in the equatorial region appear disturbed (as expected from a highly varying solar wind); (2) disconnection events (DEs) are observed only in the equatorial region where comets pierce the HCS; (3) the position angle of the plasma tail is consistent with a solar wind speed of 750 km s -1 in the polar region and an average solar wind speed of 450 km s -1 in the equatorial region. While the paradigm seems firm, it was established during a limited range of the solar cycle, and an extension to other ranges is desirable.
We test this paradigm using the published record for essentially the entire 20th century. The catalogs of M.