Supernova Light Curves

**Supernova light curves** encode explosion physics. **Type Ia** events—thermonuclear disruptions of **carbon–oxygen white dwarfs** near the **Chandrasekhar** mass—show a **fast rise**, a **peak**, then a **decline** powered largely by **⁵⁶Ni → ⁵⁶Co** decay; after calibration (**stretch**, **color**) they anchor **cosmological** distances. **Type II** supernovae arise from **core collapse** of massive stars; **II-P** shows a **plateau** from **hydrogen** recombination before a radioactive tail. The curves here are **analytic teaching shapes**, not fits to **SNfactory**, **CfA**, or **Pan-STARRS** light curves.

Who it's for: Astrophysics overview after HR diagrams; pairs with cosmic distance ladder and cosmology pages.

Key terms

  • Type Ia supernova
  • Type II-P
  • Light curve
  • Standard candle
  • Nickel decay
  • Core collapse
  • Plateau

How it works

**Type Ia** supernovae (thermonuclear disruption of a white dwarf near the **Chandrasekhar** limit) show a **fast rise**, a **peak**, then a **decline** powered largely by **⁵⁶Ni** decay—empirically usable as **standardizable candles** after **stretch**/**color** corrections. **Type II** (core collapse) are diverse; **II-P** shows a **plateau** from extended **hydrogen** recombination before a slower tail. This page draws **schematic** analytic shapes for lectures, not **Bolometric** fits to individual events.

Key equations

Standard candle: m = M + 5 log₁₀(d_L/10 pc) after calibration — real Ia need SALT2/Tripp-style terms

Frequently asked questions

Are Type Ia perfectly standard?
No—intrinsic scatter exists; cosmology uses empirical corrections and often Cepheid-calibrated ladders.
What about Type Ib/c or superluminous events?
Many other classes exist; this page highlights the Ia vs II-P pedagogical contrast only.