f the initial interstellar cloud in star formation has a mass sufficient to form hundreds of stars, how does a single star form from it?

The sun has a radius of 6.959 × 108 m and a surface temperature of 5.81 x 10° K. When the sun radiates at a rate of 3.91 x 1026 W and is a perfect emitter. What is the rate of energy emitted per square meter? Stefan-Boltzmann constant is 5.67 x 10-8 J/s-m2 K4 a) 5.6 x 107 W/m2 b) 12.8 x 107 W/m2 c) 6.4 x 107 W/m2 25.6 x 107 W/m2 5.6 x 1017 W/m2

The mass-luminosity relation describes the mathematical relationship between luminosity and mass for main sequence stars.  It describes how a star with a mass of 4 M⊙ would have a luminosity of ______ L⊙. If a star has a radius 1/2 that of the Sun and a temperature 4 that of the Sun, how many times higher is the star's luminosity than that of the Sun? (If it is smaller by a factor of 8, you would write 0.125 because 1/8=0.125) If a star has a radius 2 times larger than the Sun's and a luminosity 1/4th that of the Sun, how many times higher is the star's temperature than that of the Sun? (If it is smaller by a factor of 8, you would write 0.125 because 1/8=0.125) If a star has a surface temperature 2 times lower than the Sun's and a luminosity the same as the Sun, how many times larger is the star than the Sun? (If it is smaller by a factor of 8, you would write 0.125 because 1/8=0.125)

Which statement is most logical?  a Once gravity overcomes thermal pressure, nebulae cloud turns into molecular cloud. If it is cold and dense enough, molecular cloud might turn into protostar.  b If gravity is stronger than thermal pressure, nebulae cloud contracts into molecular cloud. If it is cold and dense enough, molecular cloud might turn into protostar.  c If a molecular cloud is cold and dense enough, it turns into a protostar. Once gravity overcomes thermal pressure, protostar might become molecular cloud.  d If a nebulae cloud is cold and dense enough, it turns into molecular cloud. If gravity is stronger than thermal pressure, molecular cloud might become protostar.

Assume that when a certain main sequence star becomes a giant gas, its luminosity increases from L to 1000 L and its radius also increases from R to 1000 R. If the initial surface temperature is T, what approximately is the final surface temperature? A. 0.032 T B. 0.18 T C. 0.0010 T D. 0.010 T

Astronomers us the P-Cygni line features in a spectrum of a supernova to... Select one alternative: ...measure the velocity of the supernova ejecta. ...to measure the rotation speed of the star that exploded. ...measure the composition of the supernova ejecta more accurately than with other lines. ...to measure the mass of the neutron star or black hole formed in the supernova.

One way to calculate the radius of a star is to use its luminosity and temperature and assume that the star radiates approximately like a blackbody. Astronomers have measured the characteristics of central stars of planetary nebulae and have found that a typical central star is 16 times as luminous and 20 times as hot (about 110,000 K) as the Sun. Find the radius in terms of the Sun’s. How does this radius compare with that of a typical white dwarf?

Place the following events in the formation of stars in the proper chronological sequence, with the oldest first and the youngest last. w. the gas and dust in the nebula flatten to a disk shape due to gravity and a steadily increasing rate of angular rotation x. a star emerges when the mass is great enough and the temperature is high enough to trigger thermonuclear fusion in the core y. the rotation of the nebular cloud increases as gas and dust concentrates by gravity within the growing protostar in the center z. some force, perhaps from a nearby supernova, imparts a rotation to a nebular cloud y, then z, then w, then x z, then y, then w, then x w, then y, then z, then x z, then x, then w, then y x, then z, then y, then w MacBook Air on .H. O O O O

D Question 9 Which of the following stages of stellar evolution creates and ejected balloon of material called a planetary nebula? O Hydrogen Fusion Multiple Shell Fusion. O Supernova O Hydrogen Shell Fusion O Helium Flash Hellum Fusion,

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