Now showing items 1-7 of 7

  • Detection of an increasing orbital period in the subdwarf B eclipsing system NSVS 14256825 

    Kilkenny, David; Koen, Chris (Oxford University Press, 2012)
    New timings of eclipses made in 2010 and 2011 are presented for the hot subdwarf B (sdB) eclipsing binary NSVS 14256825. Composed of an sdB star and a much cooler companion, with a period near 0.1104 days, this system ...
  • Further observations of Hipparcos red stars and standards for UBV(RI)C photometry 

    Kilkenny, David; Koen, Chris; van Wyk, F.; Marang, F.; Cooper, D. (Oxford University Press, 2007)
    We present homogeneous and standardized UBV(RI)C JHK photometry for over 100 M stars selected from an earlier paper on the basis of apparent photometric constancy. L photometry has been obtained for stars brighter than ...
  • HE 0230−4323 revisited: a new rapidly pulsating sdB star 

    Kilkenny, David; Koen, Chris; Worters, H. (Oxford University Press, 2010)
    HE 0230−4323 is a hot sdB star in a binary system. An earlier work demonstrated that the light curve of the system shows a strong (∼4 per cent) reflection effect and also appears to exhibit photometric variations of the ...
  • Improved SAAO–2MASS photometry transformations 

    Koen, Chris; Marang, F.; Kilkenny, David; Jacobs, C. (Oxford University Press, 2007)
    Near-infrared photometry of 599 stars is used to calculate transformations from the South African Astronomical Observatory (SAAO) JHK system to the Two-Micron All-Sky Survey (2MASS) JHKS system. Both several-term formal ...
  • A search for p-mode pulsations in white dwarf stars using the Berkeley Visible Imaging Tube detector 

    Kilkenny, David; Welsh, B.Y.; Koen, Chris; Gulbis, A.A.S.; Kotze, M.M. (Oxford University Press, 2014)
    We present high-speed photometry (resolution 0.1 s) obtained during the commissioning of the Berkely Visible Imaging Tube system on the Southern African Large Telescope (SALT). The observations were an attempt to search ...
  • Two new variable sdB stars, HE 0218−3437 and LB 1516 

    Koen, Chris; Kilkenny, David; Pretorius, M.L.; Frew, D.J. (Oxford University Press, 2010)
    We present photometry which shows that two known hot subdwarf stars, HE 0218−3437 and LB 1516, are variable. LB 1516 exhibits several frequencies in the range 12–25 cycles d−1 (periods of about 1–2 h) with amplitudes ...
  • UBV(RI)C JHK observations of Hipparcos-selected nearby stars 

    Koen, Chris; Kilkenny, David; van Wyk, F.; Marang, F. (Oxford University Press, 2010)
    We present homogeneous, standardized UBV(RI)C photometry for over 700 nearby stars selected on the basis of Hipparcos parallaxes. Additionally, we list JHK photometry for about half of these stars, as well as L photometry ...