Spectral+classification

The image below and the Powerpoint presentation were done by Ian Baker who is helping us understand how to take Spectra and understand them.

One thing that jumps out in the image is the shift in colour from blue top left to red lower right as you go down from O to M.

All images were taken with Ian's telescope and home made Specrograph:- http://scopes.wikispaces.com/Spectrograph

[|Spectroscopy Results.ppt]

The presentation shows those stars together... the types are below from the top...

O Example is Zeta Orionis - O9Ib - B-V = -0.20 at about 17000K a cooler of the O Type stars. Its a super giant well off the main sequence I would think it is well into burning helium.It may even be beyond that... We should watch out for when it starts silicon buring though... ;-) B Example is Delta Orionis - B2V - B-V = -0.16 at about 14000K - This is a main sequence star still burning hydrogen. A Example is Gamma Gemini - A0IV - B-V = +0.03 at about 9000K - This has just moved off the main sequence so its core has probably collapsed and shell helium burning is underway as is the fusing of helium to carbon in the core. F Example is Delta Equulius - FV5 - B-V = +0.5 at about 6500K - This is a main sequence star G Example is a Alpha Aquarii - G2Ib - B-V = +0.98 at about 4800K - A Giant... I guess this is a vision of the future for our own star... K Example is Alpha Taurii - K5III - B-V = +1.4 at about 3700K - A Giant destined most likely to be a white dwarf surrounded by a planetary nebula... M Example is Alpha Orion - M2I - B-V = +1.85 at about 2800K - A Giant