Tom Rauschenbach wrote:

I've noticed that stars are classified with letters of the alphabet.
This story
http://www.spaceref.com/news/viewpr.html?pid=18792
for example mentions "K stars" and "F stars". I'm wondering if this
system has a name. A Google search for "star categories" turned up
nothing useful.



Some where I have read about the origin of the seven spectral
classes O-B-A F-G-K-M, but cant locate it... but I did find some
good links...


Harvard Spectral Class sequence for Stars

http://www.physics.sfasu.edu/astro/a...inks/all5.html

http://csep10.phys.utk.edu/astr162/lect/index.html
http://csep10.phys.utk.edu/astr162/l...s/harvard.html


http://history.nasa.gov/CP-2156/glossary.htm

spectral type (or class) - classification used to sort stars by
photospheric temperature and intrinsic brightness. The seven spectral
classes O-B-A F-G-K-M, listed in order of decreasing temperature,
include 99% of all known stars. Each spectral type is divided into a
variable number of subtypes designated by Arabic numerals. Further,
stars are sorted by intrinsic brightness into luminosity classes
designated by the first five Roman numerals. In turn, these are
subdivided into a small number of subclasses designated by the first
few letters of the lower case English alphabet; for example, the Sun
is a G2 V star (also sometimes denoted as a dwarf G2 star) and
Betelgeuse (Greek letter alpha Orionis) is classified as M2 lab
(i.e., intermediate between la and lb)