Stellar Classification
esiegel | January 14, 2013"The ruins were just a reminder that what had been was no longer. That everything we are will be gone someday. That I will be forgotten." -Megan Miranda
Some four-and-a-half billion years ago, a ultra-massive cloud of cold gas and dust collapsed, giving rise to thousands of stars of all different types, from hot, massive, quick-burning blue stars down to low-mass, cool red dwarfs. And within a few hundred million years, that open star cluster dissociated, flinging the individual stars that once made it up throughout the galaxy. The lone remnant of that cluster known to us lights up our…
esiegel | October 24, 2012"The sun is a mass of incandescent gas
A gigantic nuclear furnace
Where hydrogen is built into helium
At a temperature of millions of degrees" -They Might Be Giants
It's so ingrained in us that the Sun is a nuclear furnace powered by hydrogen atoms fusing into heavier elements that it's difficult to remember that, just 100 years ago, we didn't even know what the Sun was made out of!
Image credit: Landscape Photography by Barney Delaney.
The conventional wisdom at the time, believe it or not, was that the Sun was made out of pretty much the same elements that the Earth is! Although that…
cevans | July 5, 2010
Readers, help me sort out an egregious detail of astronomical lore.
The most common method of classifying stars -- Harvard Spectral Classification -- was thought up by one of the most famous female astronomers of all time, Annie Jump Cannon. Adapted from a cumbersome older method which sorted stars into 22 alphabetical categories of observable hydrogen in their spectra, the Cannon method orders stars from hottest to coldest. This, despite being functional and elegant, left her (and us) with an unpronounceable acronym: OBAFGKM. With the recent addition of two colder categories of stars, the…