5) A star (no matter what its mass) spends most of its life
Select one: a. as a protostar.
b. as a main-sequence star.
c. as a planetary nebula.
d. as a red giant or supergiant.
6) What is the ultimate fate of an isolated white dwarf?
Select one:
a. It will cool down and become a cold black dwarf.
b. As gravity overwhelms the electron degeneracy pressure, it will explode as a nova.
c. As gravity overwhelms the electron degeneracy pressure, it will explode as a supernova.
d. As gravity overwhelms the electron degeneracy pressure, it will become a neutron star.
7) A typical neutron star is more massive than our Sun and about the size (radius) of
Select one:
a. a small asteroid (10 km in diameter).
b. Earth.
c. the Moon.
d. Jupiter.
8) What causes the radio pulses of a pulsar?
Select one: a. The star vibrates.
b. As the star spins, beams of radio radiation sweep through space. If one of the beams crosses Earth, we observe a pulse.
c. The star undergoes periodic explosions of nuclear fusion that generate radio emission.
d. The star's orbiting companion periodically eclipses the radio waves emitted by the main pulsar.
9) How does a black hole form from a massive star?
Select one:
a. During a supernova, if a star is massive enough for its gravity to overcome neutron degeneracy of the core, the core will be compressed until it becomes a black hole.
b. Any star that is more massive than 8 solar masses will undergo a supernova explosion and leave behind a black-hole remnant.
c. If enough mass is accreted by a white-dwarf star so that it exceeds the 1.4-solar-mass limit, it will undergo a supernova explosion and leave behind a black-hole remnant.
d. A black hole forms when two massive main-sequence stars collide.
10) Which of the following is not true about differences between novae and supernovae?
Select one: a. Novae are much less luminous than supernovae.
b. Supernovae eject gas into space but novae do not.
c. Novae occur only in binary star systems, while supernovae can occur both among single stars and among binary star systems.
d. The same star can undergo novae explosions more than once, but can undergo only a single supernova.
(5) b. as a main sequence star.
(6) c. As gravity overwhelms the electron degeneracy pressure, it will explode as a supernova.
(7) a. a small asteroid (10 km in diameter).
(8) b. As the star spins, beams of radio radiation sweep through space. If one of the beams crosses Earth, we observe a pulse.
(9) a. During a supernova, if a star is massive enough for its gravity to overcome neutron degeneracy of the core, the core will be compressed until it becomes a black hole.
(10) d. The same star can undergo novae explosions more than once, but can undergo only a single supernova.
5) A star (no matter what its mass) spends most of its life Select one: a....
What is the reason for two stars to have the same brightness but one being 100 times more luminous than the other? One of them is 100 times more distant One of them is 10 times more distant One of them is 1000 times more distant One of them is 4π times more distant The Brightness scale like the inverse of the square of the distance (1/R2) T F What is parallax? The distance of a star A method to...
choose A B C D QUESTION 5 When astronomers look at globular clusters they don't see any stars hotter/more luminous than our Sun. What does this mean for the age of the globular cluster? The globular cluster doesn't have enough gravity to capture any stars more massive than our sun yet. The globular cluster is younger than the typical lifetime of a star like our Sun. The globular cluster is older than the typical lifetime of a star like our...
choose correct answer. no explanation needed QUESTION 36 What does the apparent magnitude of a star tell us about that star? its mass how bright it appears from Earth its radius how much energy it is emitting QUESTION 37 What is the reason sunspots appear darker than surrounding regions on the Sun's surface? They actually are fairly bright, but appear dark against the even brighter background of the surrounding photosphere. They are too cold to emit any visible light. They...
choose A B C D QUESTION 1 Star formation in giant gas clouds is a result of competition between which forces? Light and rotation Light and dark Rotation and gas pressure Gravity and gas pressure 10 points QUESTION 2 What effect sets the largest size a star can have? The forming star is shining so strongly that it blows the collapsing gas cloud apart. If the star was any larger it would instantly form a Black Hole. If the...
6. • The Crab Nebula One of the most studied objects in the night sky is the Crab nebula, the remains of a supernova explosion observed by the Chinese in 1054. In 1968 it was discovered that a pulsar-a rapidly rotating neutron star that emits a pulse of radio waves with each revolution-lies near the center of the Crab nebula. The period of this pulsar is 33 ms. What is the angular speed (in rad/s) of the Crab nebula pulsar?...
Before leaving Alpha Centauri, you change from the shuttle to a light speed interstellar cruiser and head out deep into the galaxy to visit another binary star system - but this one is composed of dead stars! To occupy your waking travel time by reading about this star system in the "Outer Space Tourbook": Stars spend most of their lifetimes undergoing nuclear fusion in their cores, which is why they give off so much light. However, when the material necessary...
choose correct answer. no explanation needed QUESTION 31 اماں VIII w mu VII 11 OBA FG KM This figure depicts the evolutionary track of a 2 Mo star, with the various evolutionary changes indicated. During which stage does the star have an inert (non-fusing) helium core? iv vil Hi ООО viii vi QUESTION 32 VI V и VE IV 1 OBA FG KM This figure depicts the evolutionary track of a 2 Mo star, with the various evolutionary changes indicated....
m. solar nebula к. asteroid I. comet Jovlll plalie n. planetesimal 2. A star had 10 times the mass of the Sun when it was on the Main Sequence. At the end of its life it has a core with a mass two times the mass of theSn. Explin what hppdto the rest of the mas and wiy, o. lunar eclipse p. solar eclipse 9. Where did the heavy elements that most of the Earth is composed of originate? a)...