The physical conditions in SwSt 1 : the central star and the nebula.

The authors present new optical observations on SwSt 1. They estimate a reddening of E(B-V) = 0.41 mag and a distance D = 1.2±0.2 kpc to the nebula. From their data the authors derive an electron density of (1.0±0.2)×10⁵ cm^-3 and a temperature of 11400±500K. Carbon, nitrogen, oxygen, chlorine and sulphur are underabundant more or less by a factor of 2 with respect to the "cosmic" values. The central star has an effective temperature of 32000K and is losing mass at a rate of (6 - 7)×10^-8M_sun;yr^-1.