test 3a - The stellar birthline is: A. The luminosities and...

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A. The luminosities and temperatures at which protostars first become visible as cool, luminous stellar objects Which of the following would likely trigger star formation Supernovae If a star begins on the main sequence with a chemical composition of (X,Y,Z)=(0.74, 0.24, 0.02), what will be the composition in the core at the end of helium burning? (0, 0, 0.02) 0, 0, 1 Which of the following best describes a Type Ia supernova? Explosion of a white dwarf. The spectra of emission nebulae contain mainly: Emission lines. What is the source of pressure in a white dwarf that successfully resists the force of gravity? Electrons that have become incompressible (degenerate). Order the sequence of nuclear burning phases of a 15 solar mass star where C = carbon burning, Fe = iron burning, H = hydrogen burning, He = helium burning, O = oxygen burning, N = nitrogen burning, Ne = neon burning, and Si = silicon burning. Some phases may be missing in the sequence. C. H,He,C,O,Si. ….. How does general relativity describe the force of gravity? As due to a curvature of space How were the heaviest elements in the universe formed? By core nuclear burning in massive stars The interstellar medium is kept at a million kelvins by Ionizing radiation from hot O and B stars . .supernovae explosions A typical size for a NS is 30 km The HR diagram shows evolutionary tracks of protostars (dashed lines) of different massas. Dots and numbers designate positions on the tracks; lower case letters identify several lines. Some may correspond to something real and others may not. Which track corresponds to the least massive protostar:
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test 3a - The stellar birthline is: A. The luminosities and...

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