| タイトル | A search for interplanetary He II, 304-A emission |
| 著者（英） | Fahr, H.; Lay, G.; Paresce, F. |
| 著者所属（英） | Bonn Univ.|California Univ. |
| 発行日 | 1981-11-01 |
| 言語 | eng |
| 内容記述 | A survey of a region of the sky around the antisolar direction in the earth's shadow was surveyed by the extreme ultraviolet telescope on the Apollo-Soyuz mission, whose 170-620 A channel is primarily sensitive to the H II, 304-A and He I, 584-A resonance. A sharp decrease in intensity was found as the line of sight sweeps into the shadow region. Once the line of sight is contained within the shadow, a residual signal above instrumental background was observed that was independent of view direction and spacecraft position. An upper limit at the 2sigma confidence level to a possible He II, 304-A component that can escape detection by the instrument corresponds to 0.002 R, or to a column density of 10 to the 9th ions/sq cm scattering at line center. The brightest possible sources for such emissions are multiple scattering from plasmaspheric He(+) in the shadow and scattering from He(+) created by the photoionization of the interstellar wind neutral helium. |
| NASA分類 | ASTROPHYSICS |
| レポートNO | 82A13261 |
| 権利 | Copyright |
| URI | https://repository.exst.jaxa.jp/dspace/handle/a-is/413152 |
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