Astronomy: Sun Structure and Activity; Stellar Parallax; Life Cycle of Stars.

Pataasin ang iyong marka sa homework at exams ngayon gamit ang Quizwiz!

The Sun contains about ___ of the mass in our solar system.

99%

Approximately how old is the Sun?

45 billion years

A star has a parallax of 0.5 arc sec. Calculate the distance to the star in parsecs.

d=1/0.5= 2 parsecs

The parallax of a star is inversely related to its

distance

The luminosity of the Sun results from its

energy emission

1 parsec is about equal to ____ light year(s)

3.26

The temperature of the Photosphere is

Cooler than the core and corona

Fusion occurs in the Sun's

Core

If the star has a parallax of ____ arc seconds, then its distance is _____

0.25; 4 parsecs

Alpha Centauri has a parallax of 0.74 arc sec. What is the approximate distance to Alpha Centauriin

1.35 par sec

What is the approximate diameter of the Sun?

1.4 million km

Parallax is useful for measuring the distance of stars up to about ____ light year(s) from Earth.

100

Which of the following stars is most likely to have a degenerate helium core at some point?

A star that is the same mass as our Sun.

Which of the following star's would be most likely to spend the longest time on the main sequence?

A star with 1.2 solar masses

When the helium and hydrogen shells around a low mass star's core begins burning, the star will become which of the following?

AGB Giant

The parallax of nearby stars are produced by

Earth's revolution around the Sun

A low mass star will end its life as which of the following?

Black Dwarf

What will be the final state of the Sun?

Black Dwark

In the last stage of stellar evolution following a supernova, stars too massive to form neutron stars may form a

Black hole

Sunspots are _____ regions of the Sun's surface.

Cooler

About 25% of the Sun is composed of hydrogen

False

Astronomers have calculated the parallax angles of millions of stars.

False

What will happen to a low mass star on the HR diagram after it begins ejecting its envelope near the end of its life?

It will move to the left, appearing hotter as the core is exposed.

As a low mass star begins ejecting material near the end of its life, it forms what?

Planetary nebula

Describe the sun's rotation

Since the Sun is not solid, it rotates at different rates, faster at the equator and slower at the poles.

How does distance affect parallax?

The nearest stars have the largest parallax angles, while those of distant stars are too small to measure.

Which statement best describes the Sun's hydrostatic equilibrium?

The outward push of the Sun's internal pressure balances the inward force of gravity

Galileo's observation of the motion of Sunspots provided evidence for which of the following?

The rotation of the Sun

Different parts of the Sun rotate at different speeds

True

Nearby stars have large parallax angles.

True

A red giant is formed when

a star begins burning its hydrogen shell

Which is NOT true about a protostar?

it generates pressure by fusing hydrogen

Which phrase best describes the Sun's age in its stellar life cycle?

middle aged

The part of the Sun that emits visible light and is typically seen from Earth is the:

photosphere


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