1.Brown dwarfs are failed stars that never sustain p-p fusion in their cores. Wh
ID: 298005 • Letter: 1
Question
1.Brown dwarfs are failed stars that never sustain p-p fusion in their cores. Where would such a star be located on an H-R diagram?
A.above and to the left of the highest part of the main sequence
B.below and to the right of the lowest part of the main sequence
C.in the lower left corner of the H-R diagram
D.in the upper right corner of the H-R diagram
2.Dark matter is thought to dominate the mass of spiral galaxies like ours because....?
A.The orbital speeds of stars far from the galactic center are surprisingly high, suggesting that these stars are feeling gravitational effects from unseen matter in the halo.
B.Our view of distant galaxies is sometimes obscured by dark blotches in the sky, and we believe these blotches are dark matter located in the halo.
C.Although dark matter emits no visible light, it can be seen with radio wavelengths, and such observations confirm that the halo is full of this material.
D.Theoretical models of galaxy formation suggest that a galaxy cannot form unless it has at least 10 times as much matter as we see in the Milky Way disk, suggesting that the halo is full of dark matter.
Explanation / Answer
1) answer : B
Brown dwarfs are the celestial objects whose mass is between a gasgaint and a small star. It exist at the bottom right corner of HR diagram
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