X-ray/microwave relation of different types of active stars

摘要: Coronal active stars of seven classes between spectral types F and M, single double, are compared in their quiescent radio X-ray luminosities L(R) L(X). We find, largely independent stellar class, log L(X) is less than about + 15.5. This general relation points to an intimate connection the nonthermal, energetic electrons causing emission bulk plasma corona responsible for thermal X-rays. The relation, observed over six orders magnitude, suggests that heating mechanism necessarily involves particle acceleration. derive requirements simple models based on optically thin gyrosynchrotron mildly relativistic X-rays from plasma. discuss possibility a portion accelerated particles heats ambient by collisions. More likely, acceleration may occur parallel same process, but at fixed ratio.