# Assessment Instructions: Problem Set 06 — H II Region Diagnostics and the Stromgren Sphere

## Inputs to Inspect
Student submission, this problem set, the solution key, the corresponding lecture slides/notes, and the referenced dataset(s) under `materials/ASTR360/data/`.

## Grading Standard
Award credit for correct method and units first, then for the specific numeric result. A student who shows correct reasoning with a small arithmetic slip should receive most of the available credit; a student with a correct-looking number but no visible derivation steps should not. Because this is a 300-level quantitative interstellar-medium course, full marks require a genuine derivation wherever the problem set asks for one, and a genuinely reasoned (not merely asserted) interpretation wherever the problem asks for scientific judgment (e.g., honestly characterizing an idealized model's disagreement with a real object).

## Problem-Level Criteria
- Problem 1: verify correct Rosette Stromgren-radius arithmetic and a genuinely physical (not generic) explanation for the discrepancy comparison.
- Problem 2: verify the algebraic inversion for Q_H is correct and the ionization/density-bounded interpretation follows logically from the comparison.
- Problem 3: verify the student correctly identifies the Balmer decrement as an independent diagnostic from the Stromgren-radius calculation.
- Problem 4: verify the n_e^(-2/3) scaling is confirmed numerically, not just asserted.

## Resubmission Policy
Students may resubmit within one week of receiving feedback. A resubmission must show a corrected derivation, not only a corrected final number, and should reference the specific feedback comment it addresses. Regrade to a maximum of 90% of the original point value unless the error was a grading mistake.

## Common Errors to Flag
- Treating a factor-of-2 or larger model-observation discrepancy as a computational error rather than an expected idealized-model limitation.
- Confusing which diagnostic (Balmer decrement vs Stromgren radius) depends on which physical inputs.
- Sign/direction errors in the n_e^(-2/3) scaling (reporting an increase instead of a decrease in R_s for increased n_e).