What two characteristics of a star are plotted on the Hertzsprung-Russell diagram?

Question

A. Brightness and temperature
B. Brightness and age
C. Rotation and temperature
D. Rotation and age


16. We see only one side of the moon from Earth because

A. tilt of Earth on its axis causes it to face the same side of the moon.
B. the other side of the moon isn't illuminated when it faces Earth.
C. the moon rotates on its axis at the same rate at which it orbits Earth.
D. Earth's gravity holds the moon in place so it can't rotate.

Answer 1

The Hertzsprung-Russell diagram (usually referred to by the abbreviation H-R diagram or HRD, also known as a Colour-Magnitude (CM) diagram) shows the relationship between absolute magnitude, luminosity, classification, and surface temperature of stars. The diagram was created circa 1910 by Ejnar Hertzsprung and Henry Norris Russell, and represented a huge leap forward in understanding stellar evolution, or the 'lives of stars'.

An examination of the diagram shows that stars tend to fall only into certain regions on the diagram. The most predominant is the diagonal, going from the upper-left (hot and bright) to the lower-right (cooler and less bright), called the main sequence. In the lower-left is where white dwarfs are found, and above the main sequence are the red giants and supergiants. The Sun is found on the main sequence at luminosity 1 (magnitude approx. 5), around 5400K (Stellar Class G2).

There are two equivalent forms. One is the observer's form which plots the colour index of the star on one axis and the absolute magnitude on the other axis. These two quantities can be derived from observations. The theoretician's form plots the temperature of the star on one axis and the luminosity of the star on the other. These two quantities can be calculated from computer models.

Implicit in the use of the diagram is use of the Morgan-Keenan spectral classification, This stellar classification is the most commonly used. The common classes are normally listed from hottest to coldest (with mass, radius and luminosity compared to the Sun).

Answer A, therefore

The Moon. Answer C is correct. We only see one side, the same side all the time because the two bodies are "synchronously locked". i.e. the two motions (the Moon's orbital and axial rotations) are synchronised as in Synchronised Swimming.

Answer 2

Characteristics Of Stars

Answer 3

Astronomy is incredible, merely look up on the celebrities and ask your self what's available. in case you spent 0.5 the era of time on your position artwork as you probably did posting this question, you'd be done with it. Do your self a choose and take a pair of binoculars and experiment the evening sky slowly with them. you'd be surprised how significantly better ought to correctly be considered.

Answer 4

Shows you not to trust wikipedia's word all the time......that temp given for the Sun would make it a G5-6, not G2, which is 5800K.

I'll tell you the answers.....they're A and C......but you should go and look these up yourself. That way you'll actually learn what they are. You shouldn't be so lazy.......you'll never pass your grades that way. At least not honestly....unless, of course, that means nothing to you.

Answer 5

it would be so much more worth it to acutally read these answers out of your text book

A
C (i think)

Answer 6

or give the wrong answers, bozo.

when they get failing gradrs,maybe they will learn to do it themselves.

The answers are D, B

Answer 7

A
C