This panel allows you to see detailed about sector you have currently selected, it usually the one you're in, but if you use this panel with the galactic map, you can basically see information about any sector in the galaxy.
It provides information about the sun, planet and colony type if any. You can see how much manpower is granted when controlling this sector with how much money and ship parts this sector can produce per minute.
Below is the type and quantity of each station type this sector can support. As an example suns support many energy factories but little else while asteroid belts offer room for ore mines.
Finally, there's a list of all stations in the sector. Clicking an item in this list will select it for you.