1. Parallax quality cut 15 points
A source has parallax = 3.4 mas with uncertainty 0.9 mas. Compute parallax/error and state whether it passes a > 5 quality cut.
Problems
2. Distance from parallax 15 points
A source has parallax = 6.2 mas. Compute its distance in parsecs.
3. Magnitude cut 15 points
Two sources have G = 13.2 and G = 15.8. State which pass a G < 14 "bright and reliable" cut.
4. Combined sample 15 points
Five sources have (parallax mas, error mas, G mag): S1 (6.2, 0.3, 12.5), S2 (3.4, 0.9, 13.0), S3 (9.1, 0.2, 15.5), S4 (2.0, 0.15, 11.0), S5 (4.5, 1.8, 10.0). Apply both the parallax/error > 5 cut and the G < 14 cut, and report exactly which sources are retained in the final sample.
Due and Scope
Submit a clear solution with equations, units, labeled quantities, and a short narrative interpretation for each problem. Show every reduction step and state your assumptions explicitly; a correct final number without visible work receives partial credit at most.
OpenStax Companion Reading
Verify against OpenStax Astronomy 2e Chapter 19.2 (surveying the stars, parallax) before instructional release.
References and Data Sources
- Corresponding lecture slides and notes for this unit.
- OpenStax Astronomy 2e (local reference copy: references/openstax-astronomy-2e.pdf).
- Course datasets under
materials/ASTR210/data/where referenced above.