Energy balance of stellar coronae. II. Effect of coronal heating

Journal Article · Sun Aug 15 04:00:00 EDT 1982 · Astrophys. J.; (United States)

DOI:https://doi.org/10.1086/160214· OSTI ID:6718825

Hammer, R

Models of magnetically open regions in hot stellar coronae are computed; and their dependence on the total amount and the location of coronal heating is investigated in terms of the following characteristic quantities: the pressure at the base of the transition region; the maximum coronal temperature and the temperature at the critical point; the heights of the temperature maximum and of the critical point; the coronal energy losses due to radiation, wind, and thermal conduction; the mass loss; and the type of the asymptotic behavior of the solution. The relations between these quantities are discussed. Depending on the heating parameters, there exist three typical kinds of coronal models. For dissipation scale lengths L small compared to the stellar radius, the corona is radiation dominated; that is, the wind and outward conductive energy losses at the critical point are small, the base pressure is high, the coronal temperature is low, and the asymptotic behavior of the solutions is of the Parker type (Tapprox.r/sup -2/7/ for r..-->..infinity). For large L and small heating fluxes phi/sub M//sub 0/, the outward heat conduction contributes significantly to the energy losses; the coronal temperature is large, the base pressure is small, the mass loss rate is relatively small, and the asymptotic behavior is again of the Parker type. Finally, for both large L and phi/sub M//sub 0/ the corona is wind dominated; that is, the radiative and conductive energy losses as well as the base pressure are small, the coronal temperature and the mass loss rate are large, and the asymptotic behavior is of the Durney type (Tapprox.r/sup -4/3/ for r..-->..infinity).

• Research Organization: Joint Institute for Laboratory Astrophysics, University of Colorado and National Bureau of Standards, and Institut fuer Astronomie und Astrophysik der Universitaet Wuezburg, FRG
• OSTI ID: 6718825
• Journal Information: Astrophys. J.; (United States), Journal Name: Astrophys. J.; (United States) Vol. 259:2; ISSN ASJOA
• Country of Publication: United States
• Language: English

Related Subjects

640102* -- Astrophysics & Cosmology-- Stars & Quasi-Stellar
Radio & X-Ray Sources
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ATMOSPHERES
BOUNDARY CONDITIONS
ENERGY BALANCE
ENERGY TRANSFER
HEAT TRANSFER
HEATING
MATHEMATICAL MODELS
NUMERICAL SOLUTION
STAR MODELS
STELLAR ATMOSPHERES
STELLAR RADIATION
STELLAR WINDS
THERMAL CONDUCTION