Stars on the ZAMS: Mass, Metallicity, and H-R Position
Context
This station is designed to be completed quickly. Write a prediction, follow the steps, then make a claim supported by evidence from the demo.
Predict
Before using controls, predict what happens to Teff and L when mass increases along the ZAMS at fixed metallicity.
Prediction (1 sentence):
Play steps
- Use ZAMS mode with the mass slider at Z=0.02 and follow the marker along the ZAMS track.
- Hold mass fixed and vary metallicity to see how L, R, and Teff shift.
- Switch to Stefan mode, keep Teff fixed, and increase R to see the vertical shift in L.
- Turn on constant-R guides and identify the nearest guide for each state.
- Select an override preset (for example a red supergiant) and compare it against nearby ZAMS states.
Parameter table
| Parameter | Value | What to notice |
|---|---|---|
| Mass M | 1 Msun | Use as a baseline before moving to higher or lower masses. |
| Metallicity Z | 0.02 | Solar-neighborhood reference for initial comparisons. |
Explain
Use one ZAMS case and one override case to explain how assumptions change what the model is allowed to infer.
Explanation (2–3 sentences):
Claim + evidence
Claim:
Evidence (what you observed):