4. The elemental abundance analyses

We employed programs SYNSPEC (Hubeny et al. 1994) and WIDTH9 (Kurucz, private communication), respectively, to determine the helium and metal abundances. The adopted metal-line damping constants were the default semi-classical approximations, except for iron-peak element lines, whose values were based on the data of Kurucz (1995). We applied a 3% scattered light correction to account for light scattered along the direction of the dispersion, which is an appropriate value for clean optical systems (Gulliver et al. 1996).

Table 1 (click here) contains the derived He/H ratios from lines on the CASLEO spectrograms. For all three stars, these values are much less than solar and similar to those for many HgMn stars.

Table 2 (click here) summarizes the determination of the microturbulence using Fe II lines. Those for were found by demanding that the derived abundances be independent of equivalent width and those of by minimizing the standard deviation of the mean. No entries are given for HR 4487 as the Fe II lines indicated that the values might be larger than a few km s^-1, which is inconsistent with values found for other HgMn stars. The problem is that we have not observed a sufficient number of Fe II lines which are beyond the linear part of the curve-of-growth. Thus we adopt the most common value of 0.0 km s^-1 for this class of star.

Table 3 contains the metal line results from our spectra. For each line, they contain the multiplet number, the wavelength in Å, the equivalent width in mÅ, the gf value and its source, and the derived abundance (log N/N(T)) where N(T) is the total number of atoms per unit volume.

 

Wavelength (Å) HR 4487 14 Hya 3 Cen A

3867 ... ... 0.02

4009 ... ... 0.03

4026 ... ... 0.02

4121 ... ... 0.02

4169 ... ... 0.03

4388 0.04 ... 0.03

4472 0.02 0.04 0.03

4713 ... 0.05 0.02

4922 0.02 ... ...

Average 0.03 0.04 0.02

 

 

Star Species gf n

values (km/s) (km/s)

14 Hya Fe II MF+KX 30 0.3 0.3

adopted 0.3

3 Cen A Fe II MF+KX 64 1.1 1.1

adopted 1.1

gf value references: KX = Kurucz (1995), MF = Fuhr et al. (1988).
 

 

Species Castelli et al. This Paper .

He -0.55 -0 . 66

C -0.75 -1 . 01

N -0.50 -0 . 16

O 0.00 -0 . 90

Mg -0.50 -0 . 77

Si -0.20 -0 . 32:

P 1.60 1 . 59

Ar 0.00 0 . 08:

Ca -1.00 -0 . 74

Cr 0.00 0 . 51

Mn 1.40 1 . 50

Fe 0.20 0 . 28

Ni 0.00 0 . 16

Ga 3.25 3 . 55 . .