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Now showing items 21-30 of 62
HE0230–4323: an unusual pulsating hot subdwarf star
(Oxford University Press, 2007)
HE 0230−4323 is a known binary, consisting of a subdwarf star and a companion which is not
observable in the optical. Photometric measurements reported in this paper have shown it to be
both a reflection-effect and a ...
Statistical tests for changes in the amplitude, frequency or phase of a sinusoidal variation
(Oxford University Press, 2009)
The problem considered is that of testing for small changes over time in the properties of
a sinusoidal signal contaminated by noise. Two test statistics are proposed. The first is a
frequency domain statistic based on ...
Predicting gamma-ray burster redshifts from their prompt emission properties
(Oxford University Press, 2010)
This paper presents a study of the relation between gamma-ray burster redshift and several
of its prompt emission properties (spectral lag, light curve variability, peak energy, rise time
and the peak bolometric flux ...
Correcting CCD photometry of stars for seeing effects
(Oxford Univeristy Press, 2009)
Systematic variability in stellarmagnitudes, as derived from profile fitting to CCD images,may
in some instances be due to variable seeing. It is suggested that this happens in cases where the
stars are unresolved pairs, ...
Multivariate comparisons of the period–light-curve shape distributions of Cepheids in five galaxies
(Oxford University Press, 2007)
A number of published tests suitable for the comparison of multivariate distributions are
described. The results of a small power study, based on realistic Cepheid log period – Fourier
coefficient data, are presented. ...
The Nyquist frequency for irregularly spaced time-series: a calculation formula
(Oxford University Press, 2006)
Eyer & Bartholdi showed that the Nyquist frequency of irregularly sampled time-series can
be very high. In this paper, a calculation formula for the Nyquist frequency is presented. In
practice there is an upper limit of ...
KPD 0629–0016, a slowly pulsating hot subdwarf star
(Oxford University Press, 2007)
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 ...
Two new variable sdB stars, HE 0218−3437 and LB 1516
(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 ...
Near-infrared time-series photometry of six fields in the young open cluster IC 2391
(Oxford University Press, 2006)
Fields containing targets of spectral types later than M5 were monitored in JHKs for about 7 h
each. None of the targets showed variability at levels exceeding 0.02 (or smaller, in some cases).
Seven new variable stars ...
Detection of an increasing orbital period in the subdwarf B eclipsing system NSVS 14256825
(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 ...