Chapter 5
Stars
How Binary Pulse Theory's stars come into the game: whether a level can hold matter and stars, the game's Sun, star formation by the Gas Depletion Law, birth masses from the Initial Mass Function, lives and ends by mass, metals, winds, feedback and the Stellar Null Wells, each shown as the code computes it and as the player sees it.
Chapter 5
Stars
Binary Pulse Theory gives every universe its own stars. BPT Part 2.10 (The Strong Force and the Mass of Matter) ties the mass of matter to the level: a proton is the Planck mass over 2^(L/3)/14.3, so a level decides whether matter holds together, whether stars can stand, how many protons a star holds and how many stars the universe forms. BPT Part 2.9 (Gas, Stars, and the Stellar Road to the Null Well) and its formal companion, BPT Part 6.10 (Stellar Formalism: The Gas, the Stellar Mass Unit, and the Stellar Null Well), take the road from there: the gas of the Physical Nova cools and gathers, turns into stars by the Gas Depletion Law, and each star's birth mass, drawn from the Initial Mass Function, decides its type, color, brightness, life, death and remnant; only the heaviest leave a Stellar Null Well. BPT Part 3.12 (Ripples, Spin, and the Whirling Disks) adds where the metals come from and the winds that carry them out of small galaxies, and BPT Part 3.14 (Galaxies: the Wells and the Stars Around Them) adds the feedback that keeps galaxies blue and the Proto Wells that a site's first dying star fills.
The game makes this happen in stars.js and in the parts of app.js that drive it. At the Physical Nova the matter law of the level (matterLaw()) decides which of three universes this is: one of light and wells, one of matter without stars, or one with stars. In a starry universe the game sizes its Sun so the stars it draws stand for the law's count, then, every quarter flip, forms stars in its dense clouds, draws their masses, ages them, ends them by their mass, returns their gas and metals, blows winds, pushes and heats the gas around supernovae and feeding wells, and turns the heaviest dead cores into Stellar Null Wells.
What the player watches: before the Physical Nova the HUD's Stars line reads "none before the Physical Nova". After it, the faint haze of gas on the torus gathers along the filaments and lights up with points of starlight colored by type: a few large blue-white giants, swollen orange giants, many small dim red dwarfs, white dwarfs and neutron stars as small pale points, one neutron star in five blinking as a pulsar. Supernovae flash as spreading white-to-violet shells, planetary nebulae glow teal, and banners mark the first stars, the first supernova, the first white dwarf, the first neutron star and the first Stellar Null Wells. The Stars line counts them all, in real numbers for the level, and the end card and the run record keep them.
The gas the stars form from, its cooling and heat, and the mesh that moves it are in Chapter 4; the galaxies the stars gather into are in Chapter 6. Where the code departs from BPT, from the physics or from its own comments, each Part says so in its own subsection.