Light
How much energy a star gives off each second
What is Luminosity?
These "failed stars" have too little mass to ignite hydrogen nuclear fusion
What are brown dwarfs?
When a spectrum appears to have slightly longer wavelengths than it should, we say that it is shifted toward this color
What is "redshifted"?
Two stars that orbit one another are called
What are binary stars?
The HR diagram was first plotted by these two astronomers
Who were Hertzsprung and Russell?
Which magnitude star looks brightest in the sky, a magnitude 2.4 star, or a magnitude 3.8 star?
What is magnitude 2.4?
Stars that are too cool to be visible may be detected if we have instruments sensitive to this part of the spectrum, which is adjacent to visible light
What is infrared?
When a spectrum appears to have shorter wavelengths than it should, we say that its spectrum is shifted toward this color
What is "blueshifted"?
Two associated stars that can be resolved with a telescope are known as
What are visual binaries?
Hot stars tend to be on which side of the HR diagram?
What is Left?
The hottest stars tend to appear as this visible light color
What is blue?
Spectral analysis indicates that this element makes up the majority of stars (75% by mass)
What is hydrogen?
What type of motion is indicated by wider spectral lines?
What is Rotation?
Two associated stars that cannot be resolved with a telescope, but can be with spectral analysis
What are Spectroscopic binaries?
This type of star remnant has a low luminosity and small diameter, but a high temperature, and is positioned toward the bottom left of the HR diagram
What are white dwarfs?
Oh be a fine girl (guy) kiss me, is a mnemonic to help remember the decreasing temperature order of this
Many stars puff up to one of these late in life, after they have exhausted hydrogen in their core
What is a Giant?
This is the barely perceptible motion of a star across the sky
What is proper motion?
Studying binary stars can allow astronomers to calculate this physical characteristic, a measurement of inertia
What is Mass?
90% of stars will be plotted on this section of the HR diagram
What is the main sequence?
Our Sun is an example of this spectral class
What is G?
Very hot stars can become one of these huge objects, before later exploding into a supernova
What is a Supergiant?
What is Radial Motion?
When one star passes in front of another star in a regular fashion, changing the amount of light we receive
What is an Eclipsing Binary?
These stars are found across the top of the HR diagram
What are Supergiants?