Starspots and the Generation of Spherical Stellar Outflows

Abstract

view Abstract Citations (26) References (20) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Starspots and the Generation of Spherical Stellar Outflows Frank, Adam Abstract In this paper I investigate the effect starspots have on the development of AGB wind asphericities. I begin with the assumption that there are large cool starspots in an AGB photo sphere and determine the contrast in wind density for gas parcels above the spot compared with those above the "normal" phosphere. My calculations use the results of Bowen's [ApJ, 329, 299 (1988)] AGB outflow models where the wind is accelerated by radiation pressure on dust. In Bowen's models the dust condenses from gas parcels driven to large distances above the photosphere by stellar pulsation. My calculations, which assume radiative equilibrium between gas parcels and the local stellar radiation field, show that the wind above the spots will be launched closer to the star and, therefore, at higher densities than the wind above the normal photo sphere. I examine two specific cases for the distribution of starspots: the development of toroidal winds from starspots in an equatorial band and the development of of clumpy winds from a single large spot. The results show that, given the assumptions inherent in the model, significant departures from an isotropic wind can be produced by cool starspots. Publication: The Astronomical Journal Pub Date: November 1995 DOI: 10.1086/117703 Bibcode: 1995AJ....110.2457F Keywords: ISM: JETS AND OUTFLOWS; STARS: ATMOSPHERES; STARS: ACTIVITY full text sources ADS |