NSEA · Elementary Astronomy

Stellar Astronomy Basics

Stellar magnitudes, spectral classification, HR diagram and stellar evolution overview.

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  • Q1 · Stellar Astronomy Basics · HARD

    A main sequence star has a surface temperature of 12,000 K and a luminosity 400 times that of the Sun. If the Sun's surface temperature is 5,800 K, what is the approximate radius of this star in solar radii?

  • Q2 · Stellar Astronomy Basics · MEDIUM

    A star has an absolute magnitude M = +1.5 and is located at a distance of 50 parsecs. What is its apparent magnitude m?

  • Q3 · Stellar Astronomy Basics · MEDIUM

    A main sequence star has a surface temperature of 8400 K. If its luminosity is 25 times that of the Sun, what is the approximate radius of this star in solar radii? (Assume solar temperature T☉ = 5800 K)

  • Q4 · Stellar Astronomy Basics · HARD

    A binary star system consists of two stars orbiting their common center of mass with a period of 8 years. If the semi-major axis of their relative orbit is 6 AU, what is the total mass of the system (in solar masses)?

  • Q5 · Stellar Astronomy Basics · HARD

    A binary star system has two stars of masses M₁ = 2M☉ and M₂ = 1M☉ orbiting their common center of mass. If the total separation between the stars is 9 AU, what is the orbital period of the system in years?

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