Pulsations in pre-Main Sequence stars: The case of HD 34282

Abstract

HD 34282 has been found to pulsate during a systematic search for short-term photometric variability in Herbig Ae/Be stars with the goal of determining the position and size of the pre-Main Sequence instability strip. Simultaneous Strömgren photometry is used in the frequency analysis, yielding two frequencies with values of $\nu_1 = 79.5$ and $\nu_2 = 71.3$ cycle ${\rm d}^{-1}$. The main period, with a value of 18.12 min, represents the shortest period observed up to now for a $\delta$ Scuti-type pulsator. A preliminary seismic modelling, including instability predictions and rotation effects, has been attempted. Both, Main Sequence and pre-Main Sequence models predict modes in the range of 56 to 82 cycle ${\rm d}^{-1}$ (between 648 and 949 $\mu{\rm Hz}$), corresponding to oscillations of radial order n from 6 to 8. The mode identification is not discriminating due to the large error bars attached to the data, therefore, all possible non-radial and radial modes up to $\ell = 3$ are compatible with the observed oscillations.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html