B7V -B8IV comparison?

[Gasman]

Hi

After reading about different spectral class of stars and how Balmer lines increase through the B class culminating in A0 types I thought I`d compare two nearly similar spectral types to see how this looks and in between clouds tonight picked out alpha and beta Leo of class B8IV and B7V respectively. This factor about the strength of the Balmer lines would suggest that alpha Leo would have stronger lines than beta Leo but that doesn`t seem to be the case and I`m a bit puzzled why that would be?. The exposures for alpha and beta Leo were 7secs and 10 secs respectively to try and keep the intensities similar.

Anyone care to shed any light on this please? ( sorry )

Thanks

Steve

[Merlin66]

Steve,

Alf Leo is B8IVn C

Bet Leo is A3Va C....

http://simbad.u-strasbg.fr/simbad/sim-id?Ident=bet+leo&NbIdent=1&Radius=2&Radius.unit=arcmin&submit=submit+id

Can you confirm your target stars?

[Gasman]

Hi Ken

Thats me trusting Cartes du ciel info :-) !!!!

Tbanks

Steve

[Merlin66]

For the proposed IDAS ( International Database for Amateur Spectroscopy) we intend having a direct link to the Simbad database for reference and searching....

I love my CdC, but it's better at some things than others......

[robin_astro]

For the proposed IDAS ( International Database for Amateur Spectroscopy) we intend having a direct link to the Simbad database for reference and searching....

I love my CdC, but it's better at some things than others......

Even better is Brian Skiff's database of spectral types which gives all known published classifications for 657452 stars currently and counting..

http://vizier.u-strasbg.fr/viz-bin/VizieR?-source=B/mk

This gives you a nice overview of what various researchers consider the classification to be and of course most variable stars, particularly red ones vary in their spectral type significantly

Cheers

Robin