Oh, be a fine girl...!

Many years ago, an astronomer named Annie Jump Cannon (who was one of the "calculators" in Edward Pickering's lab at Harvard) classified well over 200,000 stars in the sky based on their spectra. She organized them into a sequence according to temperature that is still used today. It is:

O B A F G K M

O stars are the hottest and they are blue. M stars are the coolest and they are red. The Sun is a G type star. The mostly common mnemonic device to remember this sequence is "Oh, Be A Fine Girl, Kiss Me!"

I gave the final to my astronomy students on Monday. I included an extra credit question: create your own mnemonic device for the spectral sequence. The stipulation was that the words had to flow in some sort of logical order and form a complete sentence. I have some clever students, and there were a lot of great ones. Here are some of my favorites. (My comments are the italicized text in the parenthesis.)

• Only Beautiful And Fun Girls Keep Men (Written by a girl, I might add.)
• Old Billy Ate Fifty Giant Kansas Muffins (What exactly is a Kansas muffin?)
• Oh, Boy! Astronomy Facts Give Me Killer Migraines (Clever, and appropriate.)
• Obnoxious Boys Are Frequently Getting Kicked More (Ha! Love it.)
• Okay, Be A Fighting Guy, Karate Man. (Karate Man...so funny!)
• Overall, Brendon Always Finds Good Kissing Mates (Written by someone named Brendon.)
• Only Behaved And Fun Guys Keep Me (Probably my favorite.)

Try it. It's not as easy as it looks. :)