I want to build a planet (or satellite) that:

 - **is smaller than earth,**
 - **has a thicker atmosphere than earth** but breathable,
 - has neither intense volcanism, nor any extreme condition of that sort that would increase atmosphere density,
 - revolves around a binary star similar to [BY Draconis][1]

A higher gravity makes for a higher atmosphere density. If feels like this is the best option in order to keep the planet a peaceful place, hence my question.

**Question:**  
How is that possible? Is it coherent in such a system with at least two (small young) stars?

Bonus questions: What would the stellar system be like? Would the other telluric planets in the system necessarily look the same? Would there still be gas giants?

  [1]: http://en.wikipedia.org/wiki/BY_Draconis