# Assessment Instructions: Problem Set 05 — Jeans Instability and Collapse Timescales

## 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 the T^(3/2) scaling direction is correctly connected to increased, not decreased, instability at lower T.
- Problem 2: verify the rho^(-1/2) scaling is confirmed numerically against the sqrt(10) prediction.
- Problem 3: verify correct pc-to-AU unit conversion (1 pc = 206,265 AU).
- Problem 4: verify the inverse efficiency-timescale relationship is correctly identified as a factor of 2, not 1% or 2% directly.

## 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
- Reversing the direction of the Jeans-mass temperature dependence (claiming colder gas is more stable rather than less).
- Unit-conversion errors between pc and AU (a factor-of-206,265 error is easy to introduce).
- Confusing free-fall time with the efficiency-corrected star-formation timescale.