When a sun-like star's hydrogen runs out, at first it expands into:
A. a supergiant
B. a white dwarf
C. a star similar to our sun
D. a red giant
Answer (3)
When a sunlike star's hydrogen runs out, at first it expands into a red giant.
When a sun-like star having average mass runs out of fuel-hydrogen, its atmosphere expands and the star becomes a red-giant star. T he star would leave the main-sequence stage and enter the red-giant stage in which the pressure of the core is high which pushes the atmosphere outwards and thus the star expands. The pressure also leads to fusion of higher nuclei. The end stage of such a star would be formation of a white dwarf. A heavier star becomes a super-giant, goes supernova and forms a neutron star or a black-hole.
When a sun-like star's hydrogen runs out, it expands into a red giant. This occurs as the core shrinks and helium fusion starts, causing the outer atmosphere to expand and cool, resulting in a larger, red appearance. The answer is: D. a red giant.
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