SIMBAD references

CCD observations of stars in the young cluster IC 348 were obtained from 2004 August to 2005 January with the 0.45 m ROTSE-IIId robotic reflecting telescope at the Turkish National Observatory site, Bak{inodot}rl{inodot}tepe, Turkey. The timing analysis of selected stars whose X-ray counterparts were detected by the Chandra X-Ray Observatory were studied. The time series of stars were searched for rotational periodicity by using different period-search methods. Thirty-five stars were found to be periodic with periods ranging from 0.74 to 32.3 days. Eighteen of the 35 periodic stars were new detections. Four of the new detections were classical T Tauri stars (CTTSs), and the others were weak-line T Tauri stars (WTTSs) or G-type (or unknown spectral class) stars. In this study, we confirmed the stability of rotation periods of TTSs. The periods obtained by Cohen et al. and us were different by 1%. We also confirmed the 3.24 hr pulsation period of H254, which is a δ Scuti-type star as noted by Ripepi et al., but the other periods detected by them were not found. We examined the correlation between X-ray luminosity and rotation period for our sample of TTSs. There is a decline in the rotation period with X-ray luminosity for late-type TTSs.