# Assessment Instructions: Problem Set 03 — Hydrostatic Equilibrium for Alpha Centauri A and the Virial Mass of 47 Tucanae

## Inputs to Inspect
Student submission, this problem set, the solution key, the corresponding lecture slides/notes, and the referenced dataset(s) under `materials/ASTR310/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, full marks require a genuine derivation (not just formula substitution) wherever the problem set asks for one.

## Problem-Level Criteria
- Problem 1: 15 points — correct unit conversions and central-pressure arithmetic.
- Problem 2: 15 points — correct computed ratio and correct M vs. R⁴ scaling reasoning.
- Problem 3: 20 points — correct unit conversions and virial-mass arithmetic.
- Problem 4: 15 points — correct percent-agreement arithmetic and comparison to the M15 precedent.

## 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 to convert R☉ to meters (fourth-power sensitivity makes this error especially large here).
- Forgetting to convert km/s to m/s before squaring in the virial-mass formula.
- Treating a 20-40% agreement as a failure of the virial theorem rather than an expected limitation of the uniform-density/single-mass approximations.