Hearth is the Puppeteer homeworld and one of the Fleet of Worlds. It has a population of around one trillion and is covered by arcologies, most over one mile tall. It generates so much waste heat it no longer requires a star for warmth.
For centuries, the location of the Puppeteer homeworld was a great mystery. No entity in Known Space outside the Puppeteer race was aware of the location, despite extensive surveys, with the probable exception of Jinx-born pirate Captain Kidd who discovered the Puppeteer home system by accident, and returned in the ship Puppet Master to rob inbound Puppeteer vessels, rather than pursuing a formal blackmail arrangement. Kidd claimed the Puppeteers' home planet orbited a "red giant, undersized", in the vicinity of coordinates 23.6, 70.1, 6.0. Before dying, he passed this location along to Richard Shultz-Mann, of Wunderland.
Puppeteers were willing to pay large sums of hush money in order to suppress even trivial details about their homeworld. In 2641, it was discovered that the Puppeteers' homeworld had no moon, information deduced as a result of the single failing of General Products hulls — GP hulls are not impervious to tidal forces because the Puppeteers have no experience of tides.
The Puppeteers had to make some drastic alterations to their home system, during their history, as global warming and overindustrialisation was rapidly making their planet uninhabitable. They moved their planet further from their sun, to lessen the effects of global warming. Eventually the system was rearranged as the Fleet of Worlds.