The Universe At Large 004 - Spectral Classes
23 Nov 2015Undomyr
THE UNIVERSE AT LARGE 004 - STAR SPECTRAL CLASSESHello and welcome back to The Universe At Large. The topic of this UAL will be a short explanation of the star classes found in the milky way galaxy.
The usual order of spectral classes are shown in this image;
The T Tauri class has its own entry, the L, T, Y and Herbig stars will be covered in a later entry, as will the C, S and WR classes.
These classes are based upon the spectra they emit, not per se the colour of their visible light. A lot of classes emit the majority of their light in ranges that cannot be seen by the human eye.
The "spectral" part in spectral-class refers to the image you get when you look at the light emitted from a star with a special instrument called a spectroscope. This reveals a pattern of coloured lines, so-called Fraunhoffer Lines, which indicate what kind of elements or compounds are present in the star based upon the wavelengths of light it emits.
The image above is the spectral image from Sol, showing mostly hydrogen and helium.
Each class of star has it's own specific pattern of the dark lines and it is these patterns that determine the designation used by Stellar Cartographics and the Galaxy Map they provide.
Thank you for reading The Universe At Large 004!
Questions? Comments? Suggestions?
PM these three things and whatever else relevant to me.
See you next time.
Undomyr, signing off.