| |
 |
| Paper: |
Second Overtone RR Lyrae Stars: First Overtone Variables in Disguise? |
| Volume: |
135, A Half Century of Stellar Pulsation Interpretations: a Tribute to Arthur N. Cox |
| Page: |
52 |
| Authors: |
Kovacs, G. |
| Abstract: |
In a previous paper (Poster Proceedings, IAU Symp. No. 181) we discussed the problems in the presentation of the short periodic stars as second overtone variables in the recent MACHO survey of LMC RR Lyrae stars. We have shown that evolutionary models close to the observed period of 0.28 d have comparable first and second overtone LNA growth rates. Models with strongly excited second overtone growth rates have shorter periods, which are incompatible with the observations. These results imply that second overtone pulsation in RR Lyrae stars, if it occurs, may originate only from nonlinear mode switch. Furthermore, here we compare the light curve systematics of some 100 R Rc stars (variables from the field, clusters and the Sculptor dwarf galaxy) which also include a fair number of short periodic stars. We show that the latter group is indistinguishable from the other RRc stars. We also examine a possible evolutionary scenario which might explain the existence of such short periodic group of RRc stars. |
|
|
|
|
|
