UNIVERSE
ASTEROIDS
|
Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
|
|
|
shells that are cast away from a low-mass star
|
|
|
attracts all matter and energy that come nearby
|
|
|
a low-mass star that has shed its outer layers
|
|
|
a heavy star that expands and gives off large amounts of light
|
Detailed explanation-1: -The planetary nebula phase is a final stage in a low-mass star’s life. During this phase, the star sheds its outer layers. This creates an expanding, glowing shell of very hot gas.
Detailed explanation-2: -For low-mass stars (left hand side), after the helium has fused into carbon, the core collapses again. As the core collapses, the outer layers of the star are expelled. A planetary nebula is formed by the outer layers.
Detailed explanation-3: -The masses of planetary nebulae range from 0.1 to 1 solar masses. Radiation from the central star heats the gases to temperatures of about 10, 000 K. The gas temperature in central regions is usually much higher than at the periphery reaching 16, 000–25, 000 K.
Detailed explanation-4: -A nebula is a giant cloud of dust and gas in space. Some nebulae (more than one nebula) come from the gas and dust thrown out by the explosion of a dying star, such as a supernova. Other nebulae are regions where new stars are beginning to form. For this reason, some nebulae are called “star nurseries."
Detailed explanation-5: -They have a relatively round compact appearance rather than the chaotic patchy shapes of other nebulae-hence their name, which was given because of their resemblance to planetary disks when viewed with the instruments of the late 1700s, when the first planetary nebulae were discovered.