A dedicated ground based survey the “Nainital-Cape Survey” was initiated two decades ago to search for the low-amplitude pulsational variabilities in a sample of Ap and Am stars for their asterosesmic studies. The time-series data of the sample observed under the Nainital-Cape Survey were obtained using the one meter class telescopes located at ARIES, Nainital, India and SAAO, Cape Town, South Africa. The sample stars observed under the survey are investigated through the Kepler archive for the high-precise photometric variability. The stars available in Kepler K2 database
were then observed under ground-based differential photometry, spectropolarimetry and high-resolution spectroscopy to search for the radial velocity variations, magnetic field measurements and determination of their astrophysical parameters. The analysis of high-precision Kepler photometric time-series data revealed that the four stars namely HD73045, HD73135,HD76130 and BD +192045 exhibit long term periodic light variation and that could be due to presence of spots on their surface, hence are classified as rotational variables. Apart from these rotational variables we could not detect photometric variability in stars HD73618, HD73619, HD73574, BD+192046 and TYC1395-855-1, hence are addressed as null results. The radial velocity of HD73045 is constant upto 100m/sec. We have determined the atmospheric parameters and individual chemical abundances of the programme stars. The spot maps, probable spot sizes and the decay-time scales for the rotational variables are presented. Wavelet
analysis shows non-stationary periodic variations in the rotational variables. Apart from the rotational variables, all the non-variable stars lie outside the Delta Scuti and Doradus instability strips in the H-R diagram. All the programme stars have evolved off the ZAMS towards the TAMS except BD+192046 and TYC1395-855-1 those seem to be on the red giant evolutionary phase. Our analyses show that the four stars that were reported as null results in the ground-based observations are showing rotational variability in K2 data. However, five stars that were classified as non-variables in the Nainital-Cape survey, also did not
show any significant light variability in the Kepler K2, hence are considered as constant stars.