I think gravity works hundred percent on a planetary scale. I have a problem seeing how it could keep a nuclear bomb star from instantaneously disintegrating. It is obvious it isn't sufficient in keeping galaxies together, behaving like they do. I think electrical universe theories fills a void here.
The gravity in the center of a galaxy is essentially zero (barred absence of a supermassive black hole, eating the galaxies newborn stars), thus an electrical vortex created by a magnetic field makes a perfect explanation for the rapidly rotating plasma staroids in the center. The magnetic field sucks in electrons and protons from surrounding space, and that is the building material of the first generation stars.
https://encrypted-tbn1.gstatic.com/i...CsRa6HZAPexYgZ
We are not sucked into it, we are spun out of it!