Fine analysis of five stars of the gamma Leonis group.

Applying the methed of fine analysis to five stars of the Leonis group, we determine model parameters from spectra and colors (Tab. 7). 1w 136202, for which we have the most extensive material, is analysed relative to the sun, the other stars relative to HD 136202. Combining their effective temperatures and gravities with calculations of stellar evolution by Then (Fig. 4), we obtain "spectroscopic evolittion-parallares" SE The 5E are compared with the spectroscopic :I5p, trigonometric tr, and group parallaxes Gr (Tab. 10). We remeasure the radial velocities Q (Tab. 11) and discuss the space motion (Tab. 12). The following arguments indicate that the analysed stars are not members of a moving group: III) 105590: under the assumption that HI) 105590 is a member of the group we calculated a radial velocity QGr which differs from our measured by 18 km/s, in contradiction with Eggen's criterion for membership IQGr - el 7 km/s. The declination of the convergence point of the star differs from that of the group by A6 = 60. III) 136202: :I and 5E agree quite well whereas the disagreement with Gr is very large. HI) 155646: the differences between SE and Gr are similar to those of HI) 136202. From r:Gr this star is expected to be a giant, from 5E its position in the (M,, B - V) diagram is between main sequence and sub- giant branch (Fig. 5). HI) 208776: although parallaxes are in good agreement, A6> 100. The metal abundances of these four stars are equal to the solar values: [eMs/Sn] 0 + 0.30 (Tab. 8). HI) 208906: IQGr - el > 8 km/s. Metals show underabundances by about a factor of 3 with respect to the sun: [eMe/eM] = -0.48 + 0.30. :I5E and are in agreement, but differ from Qr- Although the criteria of motion for membership in the group are fulfilled by HI) 136202 and HI) 155646, their Gr do not lead to agreement with the line analysis and color determinations. The criteria of motion seem to be necessary but not sufficient. Finally, HI) 208906 shows that spectroscopic determination of the metal abundance may give an additional criterion for group membership. Key toords: ,` Leonis group - abundance analysis - colors - radial velocities - space motions