HR Diagrams & Binary Stars

The Hertzsprung-Russell (or "HR") diagram shows a scatter plot of stars'

• luminosity vs. temperature.

• apparent magnitude vs. temperature.

• absolute magnitude vs. temperature.

• heat & color index.

The "main sequence" on the HR diagram refers to a diagonal line or field showing

• the age of stars.

• the size in radius of stars.

• the coolest stars top left; hottest stars bottom right.

• the hottest stars top left; coolest stars bottom right.

The HR diagram was created circa 1910 by Ejnar Hertzsprung and Henry Russell and represents

• an understanding of stellar evolution.

• all of the stars in our galaxy.

• an understanding of how the Big Bang created the Universe.

• intrinsic brightness only.

Tags

NGSS.HS-ESS1-3

Blue giant stars are generally the hottest & brightest and will plot

• top left on the HR diagram.

• somewhere near the top on the HR diagram.

• top right on the HR diagram.

• off the charts on some HR diagrams.

Tags

NGSS.HS-ESS1-3

Stars like our Sun and Alpha Centauri A are about average in temperature and plot

• near the center of the main sequence.

• slightly off the main sequence in the lower left.

• towards the lower right of the main sequence.

• near the red dwarf part of the HR diagram.

Red dwarf stars that are relatively cool and dim plot

• near the lower middle of the main sequence.

• at the center of the main sequence.

• to the lower right on the main sequence.

• nowhere on the HR diagram because they are too dim.

About 80% of all stars in the galaxy are actually

• yellow stars like our Sun & Alpha Centauri A.

• red dwarf stars.

• plotted on the main sequence.

• blue giant stars like Rigel & Bellatrix.

Tags

NGSS.HS-ESS1-3

Why are red dwarf ("M" class) stars not accurately represented on the HR diagram?

• there are just too many of them

• M-class stars are not included on the main sequence

• because we don't live around one

• they are so dim that it is difficult to detect them

Tags

NGSS.HS-ESS1-3

What is "spectroscopic parallax?"

• a technique used to measure star distance beyond 330 L.Y.

• a technique used to measure star distance within 100 pc

• an apparent shift in a star's rotation rate

• an apparent shift in a star's position in the night sky

Tags

NGSS.HS-ESS1-2

Spectroscopic parallax uses a star's spectrum with ____ to measure star distances (> 330 L.Y.).

• its color and/or apparent brightness

• the doppler effect

• other stars

• its radius