IB Physics HL Astrophysics Option D.1: Stellar Quantities
State the order of planets in decreasing distance to the sun (3)
Neptune > Uranus > Saturn > Jupiter > Mars > Earth > Venus > Mercury;
State the order of planets in decreasing size (3)
Jupiter > Saturn > Uranus > Neptune > Earth > Venus > Mars > Mercury;
Define Asteroid (1)
Small rocky body that drifts around the solar system;
Define Meteorites (1)
Large meteors that land on Earth;
Explain what is meant by a comet (2)
Mixtures of rock and ice in very elliptical orbits around the Sun;
Dust tail points along path, ice path points away from the Sun;
Dust tail points along path, ice path points away from the Sun;
Define Nebulae (1)
Interstellar clouds of dust, hydrogen, helium and other ionised gases;
Distinguish between stellar clusters and constellations (1)
Constellations aren’t necessarily gravitationally bound;
Explain what is meant by a parsec (1)
Distance at which the mean radius of Earth’s orbit subtends an angle of one second of arc;
Describe what is meant by a star in hydrostatic equilibrium (2)
A balance between the inwards pull of gravity; against the outwards push of radiation pressure;
Explain what is meant by a binary star system (1)
Two stars that orbiting a common barycentre of gravity;
Explain what is meant by a visual binary system (1)
The two stars can be distinguished using a microscope;
Explain what is meant by a spectroscopic binary system (2)
The two stars can be distinguished by analysis of the spectrum of emitted light from a star;
Uses doppler’s effect;
Uses doppler’s effect;
Explain what is meant by a eclipsing binary system (1)
The two stars can be distinguished by analysis of the variation in brightness of the system;
Describe the stellar parallax method of measuring distances, including its limitations (3)
Further objects move more, relative to near objects;
Only requires AU and parallax angle to stars
/ d=1/p;
Only works for distances <100pc as further distances measurement becomes inaccurate;
Only requires AU and parallax angle to stars
/ d=1/p;
Only works for distances <100pc as further distances measurement becomes inaccurate;
Distinguish between luminosity and apparent brightness (2)
Luminosity is the total power radiated by a star;
Apparent brightness is the power received per unit area;
Apparent brightness is the power received per unit area;
Explain what is meant by black body radiation of stars(1)
Stars are considered perfect emitters, so Wien’s law can be applied;