Astronomy questions.

[gridlore]

I'm still loving the Astrogator's Handbook, but I have a question or three for those of you on my friends list with more formal astronomy training.

I'm a little confused by some of the information on the star tables. I understand basic stellar classifications, but there are notations on some of the stars I don't get. Many of the stars have extra letters after the basic type and size classification. For example, Proxima Centauri is listed as "dM5 e" I know that dM5 means that this is a dwarf M5, but what does the "e" indicate? "e" seems to be a pretty common modifier, but I also see "p" and "J" used after regular . Also, many stars are listed only by a letter. "k", "m", and "0" seem to be used in this role. what does this mean?

There's also some confusion with binary systems. Take UV Ceti. The remarks section for the companion includes the following a=5.57" P=200 years. It's obvious that P is the companion's orbital period, but what is a? Is there a good on-line source for known binaries?

Comments

[pompe.livejournal.com]

...and about the emission lines. Red dwarf stars with "e"'s are likely to be flare stars. The "J", however, I don't know much about but I think it might have to do with how the spectrum was measured.