Luminosity
Spectral
HR-Diagram
History
Misc.
100
"Oh Be A Fine Guy/Gal Kiss Me," in other words OBAFGKM.
What is the spectral classification for stars?
100
The diagonal band that runs from the upper left to the lower right of a HR diagram and is referred to this.
What is the main sequence?
100
Hertzsprung and Russel observed that most stars fell along this line in the diagram.
What is the main diagonal?
100
This star has a luminosity of one on the HR-Diagram.
What is the sun?
200
L = 4*pi*R^2*sigma*T^4. This equation holds when we approximate stars to be what?
What is the equation of a stars luminosity, if it is approximated to be a perfect spherical black body?
200
G2 is the spectral classification of a very, very, very close star.
What is the Sun?
200
This axis measures temperature on HR Diagrams.
What is the horizontal axis?
200
Cecilia Payne come to the United States in this year.
What is 1923?
200
The mass of a star decreases "downward" along this line in the HR-Diagram.
What is the main diagonal?
300
This is defined as the apparent magnitude a star would have if it were at a distance d = 10 pc.
What is the absolute magnitude of a star?
300
If a star has weak Balmer lines and strong helium lines, we conclude that is has a surface temperature above this amount.
What is 10,000 Kelvin?
300
This axis is in terms of a logarithmic scale.
What is the vertical axis, and it measures a stars luminosity.
300
These two American astronomers are named after HR-Diagram's.
What is Hertzsprung and Russel?
300
This axis is sometimes label with the color index of a star
What is the temperature (horizontal) axis?
400
Flux = L / (4*pi*d^2). This describes what type of brightness for stars?
What is an expression for a stars apparent brightness?
400
This "star" is not hot enough to fuse hydrogen in its core.
What is a brown dwarf?
400
Super giants are found in this corner of the HR-Diagram.
What is the upper right corner?
400
This person was miscredited for their discoveries in astronomy and the early twentieth century.
What is Cecilia Payne?
400
These stars branch off from the main sequence and move to the upper right corner.
What is giant or supergiant stars?
500
I Supergiant, II Bright Giant, III Giant, IV Subgiant, V Dwarf (main sequence), and VI Subdwarf.
What are the six type of Star Sizes that are classified for Luminosity?
500
This star in the constellation Orion has a Spectral classification of B.
What is Rigel?
500
These colored stars are generally younger.
What is blue stars?
500
Hertzsprung and Russel plotted these two relationships against each other.
What is a stars Luminosity vs. Temperature.
500
The spectral classification had to be extended to include the letters "L" and "T". These letters generally represent this type of star.
What is a brown dwarf?
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