Physics Stack Exchange is a question and answer site for active researchers, academics and students of physics. Join them; it only takes a minute:

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

If the sun's surface was ~ 4000K (and earth closer to compensate), the UV component of the radiation would be less. However, UV makes ozone via photolysis of oxygen. Also, the stratosphere would probably start up higher (and contain less mass) because UV heating is what's responsible for the inversion. So what is the relationship between surface UV exposure (measured in DNA damage) and star temperature, which effect "wins"?

share|cite|improve this question
Interesting aside: smaller, cooler stars may have more UV than you think. This recent article on M dwarves points out that there are non-thermal emission processes, as well as frequent violent flares in some cases. Your question is still valid, but it is probably better thought of as finding a correlation between surface UV and stellar UV, or surface UV and spectral class of the star. – Chris White Jan 2 '13 at 9:08

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Browse other questions tagged or ask your own question.