Reconsidering maximum luminosity

The suggestion that there is a maximum luminosity (maximum power) in nature has long and somewhat convoluted history. Though this idea commonly attributed to Freeman Dyson, he was actually much more circumspect his views. What certainly true dimensional analysis shows the speed of light Newton's constant gravitation can be combined define quantity P_* = c^5/G_N with dimensions (equivalently, power). Then any physical situation we must have P_{physical} =$\wp$ P_*, where $\wp$ some dimensionless function parameters. This lead authors suggest luminosity/maximum power conjecture. Working within framework standard general relativity, will re-assess conjecture, paying particular attention extent which various examples counter-examples are physically reasonable. We focus specifically on Vaidya spacetimes, an evaporating version Schwarzschild's density star. For both these spacetimes arbitrarily large. argue bound depend delicate internal features radiating object.