Coronal winds powered by radiative driving
L. B. Lucy
Astrophysics Group, Blackett Laboratory, Imperial College London, Prince Consort Road, London SW7 2AZ, UK
Received: 28 December 2011
Accepted: 10 July 2012
A two-component phenomenological model developed originally for ζ Puppis is revised in order to model the outflows of late-type O dwarfs that exhibit the weak-wind phenomenon. With the theory’s standard parameters for a generic weak-wind star, the ambient gas is heated to coronal temperatures ≈3 × 106 K at radii ≳ 1.4 R, with cool radiation-driven gas being then confined to dense clumps with filling factor ≈0.02. Radiative driving ceases at radius ≈2.1 R when the clumps are finally destroyed by heat conduction from the coronal gas. Thereafter, the outflow is a pure coronal wind, which cools and decelerates reaching ∞ with terminal velocity ≈1000 km s-1.
Key words: stars: early-type / stars: mass-loss / stars: winds, outflows
© ESO, 2012