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Blue Stars

General Information

  1. The surfaces of all stars are made of pretty much the same things in the same amounts:

    By Mass
    74% Hydrogen
    24% Helium
    2% of everything else

    NOTE: Hydrogen is the least massive element.

  2. The insides of stars are different, depending on the type of star, and what stage of life the star is in.

  3. Blue stars are the hottest and most massive stars.

  4. Blue stars fuse hydrogen in their cores, creating helium.
    A star that fuses hydrogen in its core is called a “main sequence” star.

  5. As blue stars begin to die they become larger (400 million miles across) and cooler (3000K). These stars are called red giant or supergiant stars.
    Blue stars end their lives in a gigantic supernova explosion. Often a black hole or neutron star (pulsar) is left after the explosion.

  6. If you see a red star in the sky, it is probably a blue star that has expanded and cooled to become a red giant or supergiant.

  7. Compared to other stars, blue stars live for relatively short periods of time: only about 20 million years.

What To Look For Through The Telescope

  1. Recommended eyepiece: Use the 1.25-inch 40 mm eyepiece with the spectroscope.

  2. When people look through the telescope they should see a colored band with blue on one side and yellow or yellowish-orange on the other.

Additional Spectrum Information

  1. The dark lines people are seeing in the spectrum of this blue star come from hydrogen gas.

  2. Astronomers use spectrographs, which are devices similar to this one to observe dark lines in the spectra of stars. The lines that are visible tell astronomers both what elements make up the star and their relative quantities.

  3. The spectrum of the sun has tens of thousands of lines.

  4. Refer visitors to the exhibit in the starlight room. The exhibit will show them the bright line spectra of a number of gasses.
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References
Item Updated Notes
-- -- Previously: gave typical age as most clusters “dissipate after a few billion years” – BUT http://messier.seds.org/cluster.html says an “average open cluster” has spread out after several 100 million years, only a few have age counted in billions of years.