1. INTRODUCTION  
2.1. Effective Temperatures  
2.2. Masses  
2.3. Rotational Periods  
2.4. Ages  
2.5. GJ 15B  
3. X-RAY OBSERVATIONS  
4. X-RAY DATA ANALYSIS  
5. CORONAL PHYSICAL PROPERTIES  
6. CORONAL VARIABILITY  
7. RESULTS AND DISCUSSION  
8. CONCLUSIONS