--- title: "The heat and clocks of white dwarfs" description: "Explore stored heat, crystallization and cooling ages. Derive the thermal model, analyze native cooling tables and compare original Gaia fields locally." canonical_url: "https://sandboxphysics.com/stories/white-dwarf-cooling/" language: "en" page_type: "story" alternate_languages: zh-CN: "https://sandboxphysics.com/zh/stories/white-dwarf-cooling/" last_modified: "2026-11-04" --- Six lessons · White dwarf cooling and crystallization # The heat and clocks of white dwarfs Sandbox Physics · 2026-11-03 A white dwarf keeps shining after its main nuclear furnace fades. Follow its stored heat into light, watch a shell freeze, then ask what brightness can tell us about time. The route leads from a physical picture to calculations, original data and the papers on floating crystals. ## A physical picture, then a calculation [1 · L1 Why white dwarfs cool so slowly Stored heat keeps a white dwarf shining. Follow the cooling, the release of latent heat and the extra energy that can delay its stellar clock.](https://sandboxphysics.com/stories/white-dwarf-cooling/why-white-dwarfs-cool-slowly/) [2 · L1 Where a dead star keeps its heat Separate degenerate support from thermal energy. Count ions, derive a first cooling time and distinguish core temperature from the photosphere.](https://sandboxphysics.com/stories/white-dwarf-cooling/degenerate-support-and-stored-heat/) [3 · L2 How crystallization slows white dwarf cooling Derive the latent plateau, Debye limits and a controlled Mestel envelope. Track every heat term through a two-shell freezing example.](https://sandboxphysics.com/stories/white-dwarf-cooling/latent-heat-and-white-dwarf-cooling/) [4 · L3 Inferring a cooling age from brightness Build a conditional age likelihood with an explicit time prior. Test uneven sampling, model assumptions and a failed sparse quadrature.](https://sandboxphysics.com/stories/white-dwarf-cooling/cooling-clocks-and-age-likelihoods/) [5 · L3 Compare white dwarf cooling models with original Gaia data Fetch named DR3 fields locally, verify fixed MIST inputs and recompute conditional age comparisons, native holdouts and published cooling delays.](https://sandboxphysics.com/stories/white-dwarf-cooling/mesa-gaia-cooling-model-comparison/) [6 · L4 Why crystals can float inside a white dwarf Read fixed Bauer and Bédard papers from phase separation to neon distillation, including the composition prescription, smoothing and open questions.](https://sandboxphysics.com/stories/white-dwarf-cooling/white-dwarf-phase-separation-distillation/) [Open the crystallizing core](https://sandboxphysics.com/labs/white-dwarf-crystallization/) ## Calculate from the original model inputs The small archive contains fixed licensed MESA structures, MIST and STELUM outputs, standalone Python, units and original-input hashes. Its README separates seven model-only commands from the reader-local Gaia branch. Neither the website Engine nor installed scientific tools are included. - [white-dwarf-cooling-science.zip](https://sandboxphysics.com/stories/white-dwarf-cooling/materials/white-dwarf-cooling-science.zip) 0.908 MB - [include-manifest.json](https://sandboxphysics.com/stories/white-dwarf-cooling/materials/include-manifest.json) 0.008 MB white-dwarf-cooling-science.zip 907651 bytes SHA-256: 80a79ecda6908ce228f04a0c65b06efc918b8f75e23f21cb0b2a479b71032a8a include-manifest.json 8262 bytes SHA-256: fb07cf905b8862cfa73eacf46ecff53a715f77658d993b7333fadb4ee489a3e5 Dependencies, observations and reuse Reference environment: Python 3.12.12, NumPy 2.4.4, SciPy 1.17.1 and Matplotlib 3.10.8. Install these separately before following the offline commands; no MESA or STELUM installation is required. New standalone Python is MIT, and our figures and documentation are CC BY 4.0. Original model attribution and source licences accompany the files. Gaia source rows, per-object results and Gaia point figures are excluded. The archive supplies seven named queries and an explicit reader-run fetcher. Obtain observations locally under the current Gaia licence and ESDC terms; the public lessons use synthetic or licensed native-model figures. The cold replay used an existing private cache and made no fresh Gaia request. [Gaia licence](https://www.cosmos.esa.int/web/gaia-users/license) · [ESDC terms](https://www.cosmos.esa.int/web/esdc/terms-and-conditions)