Paper presented at the EGS General Assembly, 21-25, April, 1997, Vienna, Austria
Much alike the coma of an active comet, the ionosphere of non-magnetic planets contributes appreciable numbers of charged particles to the solar wind. Such ions with various energy spectra have been found previously at close distance downstream of Venus and Mars. On the occasion of the June,1996 inferior conjunction with Venus, cool Tail Ray O+ and C+ were detected at the SOHO position by the CELIAS-CTOF solar wind mass spectrometer. Flux densities measured of the order of the nominal solar wind oxygen exhibit at large distance the in-situ observation of a celestial body's tail.