As Veygaar said size is off balanced so realistically everything is false in some way.
Like a Lib Dread for exapmle in reality compared to Manhattan
the planet itself should be half the size of the ship. In fact I dont
think large ships realistically can land on planets thus dying.
As for the sun...well its just broken...They're really just ice cubes in the sky that emit heat.
EDIT: Hone increasing the sun corona radius is a bad idea in many cases. Some planets are rather close to the sun, and stations.