The nearby interstellar medium

The high dispersion spectrometer on board the International Ultraviolet Explorer (IUE) satellite was used to observe interstellar absorption lines in Rasalhague (Alpha Oph). This star is located 18 pc from the sun in the direction of the North Polar Spur, a prominent radio continuum feature in the Ophiuchus region of the sky. The satellite results, combined with previous interstellar line data and observations of the 'local interstellar wind' and soft X-ray emission, support earlier suggestions that the sun is immersed in a supernova remnant which may be an extension of the 'Loop I' or 'North Polar Spur' supernova remnant seen in the Scorpius-Ophiuchus region of the sky.