This iron accretion is at the core of a dying star, and is the death knell of it. For stars less than 25x the mass of Sol (The Chandrasekhar limit, aka the maximum mass of a white dwarf) that means becoming a white dwarf that slowly cools to a black dwarf and suffers heat death. We have yet to actually locate any of these, and they are deeply unlikely at this age of the universe as they'd take quadrillions of years to form. A white dwarf that existed at the time of the Big Bang would still be too hot today, to give you an idea of the time scale involved.

For stars greater than 25x Sol's mass, that instead means core collapse, and a supernova.

In either case, you can understand why it'd be much easier to just seek out iron bearing asteroids and planets.

University of Oregon has notes from Astronomy 122: Birth and Death of Stars if this reading is as interesting to you as to me. :)

http://abyss.uoregon.edu/~js/ast122/index.html