Spectral classification

A Stars

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Lines identification

Main sequence

Individual spectra

Luminosity effect

Peculiar B Stars

The specta of B-type stars are dominated by the Balmer lines of hydrogen and lines of neutral Helium, He I.
The Balmer lines strenghten throw the B-type stars into the A-type stars, coming to a maximum for A2 spectral type
The neutral helium lines strengthen through the O-type stars, come to a maximum at a spectral type of B2 and then weaken, finaly disappearing at a spectral type of about A0

Parameters for the B-type stars of the main sequence

	Mass	Radius	Temperature	Luminosity	Main sequence
High range	2.4	1.55	7100 K
Low range	1.6	1.87	9700 K

 

Plank curve for T = 20000 K and T = 10500 K	Comparison of radius of extreme B-type main stars (blue) and Sun (Orange)

 

Peculiars A-Type stars :

Helium anomalies	Helium strong stars	HeI strong	Sigma Ori E Delta Ori C	Photometric and spectroscopic variations of the ordrer of days
	Helium weak Stars	HeI weak + unusual strenghts of ceratin metalic lines (Si II, ...)
Emission lines	Be Stars	Emission of one or more Balmer lines
	B[e] Stars	Forbidden emission lines [FeII] and [OI]

Lines identification

B Main sequence from 3800 to 7000 angströms

Main sequence from B0 to B9.5

B0V
B1V		HD 43112 Mag V = 5.9 14-03-2013 _B1V_hd43112_20130314_911
B2V		HD 39698 Mag V = 5.9 14-03-2013 _B2V_hd39698_20130314_820
B3V		HD 41753 Mag V = 4.4 14-03-2013 _B3V__hd41753_20130314_868
B4V		90 Leo Mag V = 5.9 01-04-2013 _B4V_90leo_20130401_882 Pickles B3V
B5V		HD 42545 Mag V = 4.9 14-03-2013 _B5V_hd42545_20130314_893
B6V		HD 43461 Mag V = 6.63 28-03-2013 _B6V_hd43461_20130320_782
B7V		HD 43153 Mag 5.4 14-03-2012 _B7V_hd43153_20130314_880
B8V		HD 41040 Mag 5.1 14-03-2012 _B8V_hd41040_20130314_831
B9V		HD 66552 Mag 6.15 02-04-2012 _B9V_hd66552_20130402_850
B9.5V		HD 42509 Mag 5.1 14-03-2012 _B9_5V_hd42509_20130314_858