Stellar Spectral Types: OBAFGKM
Explanation:
Astronomers divide stars into different
spectral types.
First started in the 1800s,
the spectral type was
originally meant to classify the strength of
hydrogen
absorption lines.
A few types that best describe the
temperature of the star remain in use today.
The seven main
spectral types OBAFGKM are
shown above with the spectrum of a
single "O" star at the top followed by two
spectra each from the progressively cooler designations,
respectively.
Historically, these letters have been remembered with the
mnemonic "Oh Be A Fine Girl/Guy Kiss Me."
Frequent
classroom contests,
however, have come up with other more/less politically correct
mnemonics such as
"Oven Baked Apples From Grandpa's/Grandma's Kitchen. Mmmm."
Our
Sun has
spectral type "G".
Authors & editors:
Robert Nemiroff
(MTU) &
Jerry Bonnell
(USRA)
NASA Web Site Statements, Warnings,
and Disclaimers
NASA Official: Jay Norris.
Specific
rights apply.
A service of:
LHEA at
NASA /
GSFC
& Michigan Tech. U.
