Early last century, Bates spent 16 years living among the people of South Australia's Great Victoria Desert, recording their language, customs, and oral traditions, according to one of the study's authors, Dr Duane Hamacher of the University of New South Wales.
Hamacher and co-author Trevor Leaman collected Bates' published accounts and journal entries as part of an ongoing project to develop a complete picture of Aboriginal sky knowledge and star lore.
We present a study of OGLE light curves of red giant stars exhibiting long secondary periods (LSPs) - an enigmatic phenomenon commonly observed in stars on the upper red giant branch and asymptotic giant branch. We show that the light curves of LSP stars are essentially identical to those of the spotted variables with one dark spot on their photospheres. Such a behavior can be explained by a presence of a dusty cloud orbiting the red giant together with a low-mass companion in a close, circular orbit. We argue that the binary scenario is in agreement with most of the observational properties of LSP variables, including non-sinusoidal shapes of their radial velocity curves.
We present 855 cataclysmic variable candidates detected by the Catalina Real-time Transient Survey (CRTS) of which at least 137 have been spectroscopically confirmed and 705 are new discoveries. The sources were identified from the analysis of five years of data, and come from an area covering three quarters of the sky. We study the amplitude distribution of the dwarf novae CVs discovered by CRTS during outburst, and find that in quiescence they are typically two magnitudes fainter compared to the spectroscopic CV sample identified by SDSS. However, almost all CRTS CVs in the SDSS footprint have ugriz photometry. We analyse the spatial distribution of the CVs and find evidence that many of the systems lie at scale heights beyond those expected for a Galactic thin disc population. We compare the outburst rates of newly discovered CRTS CVs with the previously known CV population, and find no evidence for a difference between them. However, we find that significant evidence for a systematic difference in orbital period distribution. We discuss the CVs found below the orbital period minimum and argue that many more are yet to be identified among the full CRTS CV sample. We cross-match the CVs with archival X-ray catalogs and find that most of the systems are dwarf novae rather than magnetic CVs.
Authors: A.J. Drake, B.T. Gaensicke, S.G. Djorgovski, P. Wils, A.A. Mahabal, M.J. Graham, T-C. Yang, R. Williams, M. Catelan, J.L. Prieto,C. Donalek, S. Larson, E. Christensen
The cataclysmic variable V893 Sco is an eclipsing dwarf nova which, apart from outbursts with comparatively low amplitudes, exhibits a particularly strong variability during quiescence on timescales of days to seconds.The present study aims to update the outdated orbital ephemerides published previously, to investigate deviations from linear ephemerides, and to characterize non-random brightness variations in a range of timescales. Light curves of V893 Sco were observed on 39 nights, spanning a total time base of about 14 years. They contain 114 eclipses which were used to significantly improve the precision of the orbital period and to study long-term variations of the time of revolution. Oscillations and similar brightness variations were studied with Fourier techniques in the individual light curves. The orbital period exhibits long-term variations with a cycle time of 10.2 years. They can be interpreted as a light travel time effect caused by the presence of a giant planet with approximately 9.5 Jupiter masses in a 4.5 AU orbit around V893 Sco. On some nights transient semi-periodic variations on timescales of several minutes can be seen which may be identified as quasi-periodic oscillations. However, it is difficult to distinguish whether they are caused by real physical mechanisms or if they are the effect of an accidental superposition of unrelated flickering flares. Simulations to investigate this question are presented.