THE MOST RESONANT PULSATION FREQUENCY OF DELTA-SCUTI STARS

Pulsation of the Sun with a period of P-0 approximate to 160 min disco vered about two decades ago, is still waiting explanation. In view of the hypothesis about its cosmological origin, and attempting to find s ignature of this P-0 periodicity among other (short-period variable) s tars, the pulsation frequencies of delta Sct stars are subjected to sp ecific analysis. With a confidence level approximate to 3.8 sigma it i s found that the frequency nu(0) = P-0(-1) approximate to 104 mu Hz, w ithin the error limits, appears indeed to be the most ''resonant'' one for the total sample of 318 pulsating stars of delta Sct type (the mo st commensurable, or ''synchronizing'', period for all these stars occ urs to be 162 +/- 4 min). We conjecture that a) the P-0 oscillation mi ght be connected with periodic fluctuations of gravity field (metrics) , and b) the primary excitation mechanism of pulsations of delta Sct s tars, reflected by this ''ubiquitous'' P-0 resonance, must be attribut ed perhaps to superfast rotation of their inner cores (their rates ten d to be in near-resonance with the ''universal'' nu(0) frequency). The arguments are given favouring a cosmological nature of the P-0 oscill ation.