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MCQIntermediateGalaxies & Extragalactic Astronomy
USAAAO — 2024 First Round
Question 24
Tara has become obsessed with X stars and decides to look for them in other galaxies. She observes one on the edge of a galaxy with radius r = 15 × 10³ pc. She estimates that the star is moving with a speed of v = 270 km/s. What is a good estimate for the mass of the galaxy in unit mass of the sun?
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Source
USAAAO 2024 First Round, Question 24. Question text, choices, and answer were transcribed from the official USAAAO exam and solutions PDFs.