Spectral classification

B 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
3
3
10 500 K
95
10 My
Low range
18
8.4
25 000 K
52 000
400 My

 

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

 

Peculiars B-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

 

 

 

 

 

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