3 Stellar parameters

The effective temperatures were estimated using the Strömgren photometric indices (available for the program stars through the WEBDA data base, see Mermilliod 1999) by means of the numerical code written by T.T. Moon (based on the grid published in Moon & Dworetsky 1985) and modified by Napiwotzki (1994). In the WEBDA data base, however, the $\beta$-index is given for only two of our program stars. For the remaining ones we used either the measurements given in the paper of Schönberner & Napiwotzki (1994), or obtained by Schönberner (unpublished) with the same technique as explained in Schönberner & Napiwotzki (1994).

In cases where H$\gamma$ and H$\beta$ profiles were available (cf. Table 1) the gravities were specified by matching observed and calculated profiles. The profiles of the hydrogen lines were calculated with the help of the SYNSPEC code (Hubeny et al. 1994). For K88, K316 and K1270 hydrogen profiles are not available, and we used gravities determined by photometry. However, for K316 and K1270 the photometrically determined gravities appeared to be inconsistent with their positions in the HR diagram (see Fig. 4 from Breger 1982). For the less evolved star, K316, we adopted $\log g = 4.0$, and for K1270 $\log~g = 3.5$. Note that these adopted gravities differ $\approx$ 0.4 dex from the photometrically estimated ones, but this difference has a small influence on the derived abundances in the temperature region in question.

The finally adopted effective temperatures and gravities are collected in Table 2. Note that for K409, K677, K1211 and Vega the values given in Schönberner & Napiwotzki (1994) were used.

Projected rotational velocities were determined by matching observed and calculated profiles of the hydrogen and/or metallic lines (mainly Mgii) and are also listed in Table 2.

 

 

Table 2: Parameters of program stars

Knum	$T_{\rm eff}$(K)	$\log g$	$v\sin i$(kms-1)
K88	8900	3.7	80
K316	8950	4.0	25
K371	8500	3.7	45
K409	9480	4.2	140
K677	10680	3.6	40
K746	8600	3.5	20
K1211	12630	3.6	30
K1270	8300	3.5	25
Vega	9500	4.0	22