This element was discovered by J. Gahn in 1774 in Stockholm. The name probably comes from magnes (magnet) because of the magnetic properties of the manganese are pyrolusite.

Ionization energies
MnI 7.4 eV, MnII 15.6 eV, MnIII 33.7 eV.

Absorption lines of MnI

Table 1. Equivalent widths of MnI

  4030 (two resonance lines)   6022(27)    

Group V Ib V III Ib

B9 0.013        
A1 0.027        
A2 0.04        
A7 0.23        
F2   0.40      
F4 0.36   0.045    
F5     0.083   0.068
F6 0.41   0.045    
F8 0.36   0.060   0.090
G0 0.34   0.130   0.165
G1 0.56       0.139
G2     0.11   0.149
S 0.326   0.096    
G5 0.45   0.15   0.166
G8     0.14(IV) 0.16 0.203
K0     0.16 0.165  
K2     0.16   0.238
K3       0.245 0.323
K5     0.22   0.205
M0     0.16    
M2         0.200

MnI (for instance 4030) lines appear in A-type stars and increase in strength toward later types. For later types a positive luminosity effect exists (see the line at 6022).

Emission lines of MnI
The 4032 blend appeared in emission during one flare of an RS CVn star (Doyle 1991), probably produced by fluorescence.

The blend at 4032 is in emission at post-maximum phases in long-period variables (Merrill 1947). Around minimum light one finds instead lines of [Mn I] (Querci 1986).

Figure 32

Absorption lines of MnII

Table 2. Equivalent widths of MnII

  3482(3)   4206(7)  

Group V Ib V Ia

B8       0.045
A0 0.05 0.16   0.040
A1     0.011  
A3   0.342(0)    
F0       0.120
F2       0.141(Ib)
S 0.153   0.041  

MnII (for instance 4206) lines appear in late B-type stars and grow in intensity toward later types. A positive luminosity effect exists.

Emission lines of MnII
MnII emissions are seen in one typical B[e] star (Swings 1973). MnII emission lines appear in the spectra of long-period variables around maximum light, in TTau stars (Appenzeller et al. 1980) and in some VV Cep stars.

Behavior in non-normal stars
Mn lines are very strong in the spectra of the so-called Hg-Mn subgroup of Bp stars. W(4030) = 0.040 and W(4206) = 0.100 (Kodaira and Takada 1978).

Gratton (1989) has analyzed the behavior of Mn in metal-weak stars and found that in general Mn is underabundant with respect to Fe, by a factor of two except in stars where the metal weakness is small, i.e. Fe / H > -1 dex. This implies that Mn cannot be taken as a typical metal. According to Wheeler et al. (1989) Mn is also slightly underabundant in globular cluster stars. Peterson et al. (1990) found that Mn is underabundant in an extreme metal-weak globular cluster giant by a factor of ten, suggesting that the deficiency of Mn may change with increasing metal deficiency.

Mn seems to be normal in S-type stars (Fujita et al. 1963).

Mn occurs in the form of Mn55. It has ten unstable isotopes and isomers of which the longest lived is Mn53, with a half life of 2 × 106 years.

Mn can be produced either by explosive nucleosynthesis or by the nuclear statistical equilibrium process.

Published in "The Behavior of Chemical Elements in Stars", Carlos Jaschek and Mercedes Jaschek, 1995, Cambridge University Press.