# Assessment Instructions: Problem Set 02 — Radiative Gradient and the Schwarzschild Criterion for Sirius A’s Envelope

## Inputs to Inspect
Student submission, this problem set, the solution key, the corresponding lecture slides/notes, and the referenced dataset(s) under `materials/ASTR330/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 course exceeding ASTR 310's own rigor, full marks require a genuine derivation (not just formula substitution) wherever the problem set asks for one.

## Problem-Level Criteria
- Problem 1: 20 points — correct substitution and arithmetic in the radiative-gradient formula.
- Problem 2: 15 points — correct comparison and Schwarzschild classification.
- Problem 3: 15 points — correct use of the direct L proportionality.
- Problem 4: 20 points — correct, intellectually honest reconciliation with the real A-type-star structure, not an overclaimed match.

## 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
- Forgetting the fourth-power temperature dependence in the denominator of the radiative-gradient formula.
- Claiming the illustrative single-point classification proves Sirius A’s full envelope structure, rather than acknowledging its limitations.
- Confusing convective envelopes (Sun-like) with convective cores (Sirius-A-like) when discussing real stellar structure.