Browsing by Author "Green, E.M."

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    KPD 0629–0016, a slowly pulsating hot subdwarf star
    (Oxford University Press, 2007) Koen, Chris; Green, E.M.
    The results of nine CCD photometric observing runs on KPD 0629–0016 are presented. During six of the runs measurements were obtained alternately through B and V filters. Four periodicities, for which there is good agreement between the frequencies identified in the B and V data, were extracted: these lie in the range 46–81 min. A fifth lower frequency appears to be definitely present, but is very uncertain due to aliasing. The ratios of the mode amplitudes measured in B and V, and the phase differences between variations in the two colours, are compatible with pulsation theory.
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    PG 0907+123 and JL 194: slowly pulsating hot subdwarf stars
    (Oxford University Press, 2010) Koen, Chris; Green, E.M.
    Multicolour time-series photometry of two newly discovered slowly pulsating sdB stars (V1093 Her stars, also known as PG 1716 stars) is described. Both stars are fairly bright and appear, from the limited amount of data, to have rich pulsation spectra. Given that the amplitudes of variation of both stars are also large compared to most PG 1716 stars, both are good candidates for extensive follow-up observations.