Idaho Skies Transcript for July 12th and 13th

PAUL
Welcome to Idaho Skies for July 12th and 13th. We’re your hosts, Paul...


RACHEL
...and Rachel.


PAUL
Astronomers classify stars based on their spectral characteristics.


RACHEL
These characteristics, astronomers discovered, are related to a star’s temperature.


PAUL
And the factors controlling the surface temperature of a star are its mass and age.


RACHEL
This means astronomers can determine the mass and age of a star by looking at its spectrum.


PAUL
There are seven traditional groups that astronomers use to classify stars.


RACHEL
The groups are O, B, A, F, G, K, and M.


PAUL
You can remember this sequence with the sentence, Oh be a fine girl, kiss me.


RACHEL
So okay, obviously an old male astronomer created this mnemonic.


PAUL
The hottest stars and therefore the most massive are O stars.


RACHEL
These supergiant stars shine with an intense blue-white light that’s rich in ultraviolet.


PAUL
But their mass and intensity means they won’t live very long.


RACHEL
The coolest stars are the red dwarf stars.


PAUL
Red dwarfs have low masses and fuse their hydrogen at just a trickle.


RACHEL
So they’ll live for over a trillion years in some cases.


PAUL
Our sun is a G star, or slightly below average in the classification scale.


RACHEL
However, there are many more M class stars than there are O class stars.


PAUL
Which means the sun is actually larger and hotter than the average star found in the Milky Way galaxy.


RACHEL
Astronomers have further subdivided their stellar classification scale into ten numbers per class.


PAUL
The numbers go from 0 to 9 and on this scale.


RACHEL
And the sun is a class G2 star on this scale.


PAUL
That’s Idaho Skies for the 12th and 13th of July.


RACHEL
Be sure to follow us on Twitter @IdahoSkies for this week’s event reminders and sky maps.
For Idaho Skies this is Rachel...


PAUL
...and Paul.


RACHEL
Dark skies and bright stars.