Imagine Home  |   Teachers' Corner   |   Current page Blackbody Radiation and Wien's Law 1. Solve Wien's Law for T, substitute in the values for wavelength. With the temperature you obtain, look on the H-R diagram for the corresponding spectral class. (a) 9656 K Class A; (b) 19,313 K Class B; (c) 5267.2 K Class G; (d) 2317 K Class M 2. Substitute the temperatures into Wien's Law and obtain the wavelengths of the peak emission. Look up on a chart of the EM spectrum which region the wavelength falls into. (a) 289.7 cm radio; (b) 3.62x10-4 cm infrared; (c) 1.93x10-5 cm ultraviolet; (d) 1.65x10-7 cm X-ray Extension: No astronomical objects are as cold as 0.001 Kelvin. The radio emission we observe is produced by electrons moving in magnetic fields (this is called synchrotron radiation). Bigger than a Breadbox? Using the equation: distance = velocity x time, Cygnus: 9.14x1014 km; Crab: 4.46x1013 km; Tycho: 6.96x1013 km; SN1006: 9.37x1013 km The supernova occurred in the year 1604 and is known as Kepler's supernova. It was observed and documented by the astronomer Johannes Kepler. A Teaspoonful of Starstuff Using the equation: mass = density x volume, We are given that the volume of interest is 5 cm3. So what is the density of each of the objects? Density equals mass/volume, and the volume of a sphere is 4/3 πr3, where r is the radius of the sphere. Plugging in the values for each of the types of stars, we find that our teaspoon of the Sun would contain 7.0 grams; of the white dwarf would contain 9.5x106 grams; of the neutron star would contain 3.3x1015 grams. By looking up the density of water, air, and iron, you can calculate that each would be 5.0 grams, 6.5x10-3 grams, and 39.4 grams, respectively. Crossing the Event Horizon 1. Using the Schwarzschild equation, we input the mass of Jupiter (1.9x1027 kg), the Gravitational constant (G = 6.67x10-11 m3/kg-sec) and the velocity of light (3x108 m/sec) to see that the event horizon of a Jupiter-mass black hole would occur at 2.96 meters. Download a pdf version.
 Imagine the Universe is a service of the High Energy Astrophysics Science Archive Research Center (HEASARC), Dr. Alan Smale (Director), within the Astrophysics Science Division (ASD) at NASA's Goddard Space Flight Center. The Imagine Team Acting Project Leader: Dr. Barbara Mattson All material on this site has been created and updated between 1997-2012.

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