Estimate of interstellar helium parameters from Prognoz 6 and Voyager 1/2 - EUV resonance glow measurements taking into account a possible redshift in the solar line profile
Abstract
Voyager 1 and 2 observations at 58.4 nm are used to reanalyze the He I 58.4 nm interplanetary resonance glow measurements made by two EUV photometers aboard Prognoz 6. It is shown that model fitting using a low temperature (7000 + or - 2000 K) and velocity (21.5 + or - 2.5 km/s) resolves several contradictions concerning the physics of the coupling between neutrals and protons at the heliopause and the comparison with independent measurements of the solar line width. New solar parameter values of 36 + or - 6 km/s for the solar line half width at 1/e, 9 + or - 3 km/s for the redshift of the solar line, and 1.4 (+ 0.6 - 0.3) x 10 to the 7th for the lifetime are proposed. It is pointed out that if the redshift assumption is valid, a weak differentiation between helium and hydrogen at the heliospheric interface is implied.
- Publication:
-
Astronomy and Astrophysics
- Pub Date:
- July 1988
- Bibcode:
- 1988A&A...201..113C
- Keywords:
-
- Extreme Ultraviolet Radiation;
- Helium;
- Interstellar Gas;
- Red Shift;
- Satellite Sounding;
- Solar Spectra;
- Heliosphere;
- Prognoz Satellites;
- Ultraviolet Spectra;
- Voyager 1 Spacecraft;
- Voyager 2 Spacecraft;
- Astrophysics