The 2017 Presidential Address: Amateur astronomers and the new golden age of cataclysmic variable star astronomy

2018 March 22

Jeremy Shears

The study of cataclysmic variable stars has long been a fruitful area of co-operation between amateur and professional astronomers. In this Address, I shall take stock of our current understanding of these fascinating binary systems, highlighting where amateurs can still contribute to pushing back the frontiers of knowledge. I shall also consider the sky surveys that are already coming on stream, which will provide near continuous and exquisitely precise photometry of these systems. I show that while these surveys might be perceived as a threat to amateur observations, they will actually provide new opportunities, although the amateur community will need to adapt and focus its efforts. I will identify areas where amateurs equipped for either visual observing or CCD photometry can make scientifically useful observations.

Introduction
It is often said that astronomy is one of the few remaining sciences where amateurs can still contribute to research, and the study of variable stars is one of the fields cited to exemplify this. In my 2016 Presidential Address, I reviewed how members of the BAA Variable Star Section (VSS), often equipped with only modest equipment, have contributed important observations that have helped push back the frontiers of variable star science for more than 126 years.  The VSS observations database in fact extends back to 1840, some 50 years before the Association was founded, and now contains nearly three million observations.

In this my second Presidential Address, I shall focus on one particular type of variable star, the Cataclysmic Variables (CVs). The study of CVs by amateur astronomers has underpinned breakthroughs in understanding the behaviour of these systems. Amateurs have been involved in the discovery and characterisation of new CVs, and the VSS database contains some exquisite long-term visual lightcurves, which in recent years, as new technologies have emerged, have been supplemented by CCD photometry. Nowadays it is common for amateurs and professionals to cooperate in this research and jointly to publish the results in the scientific literature. While amateurs might have relatively small telescopes, they do have access to them whenever they choose (weather permitting!) and because they are located around the world at different longitudes, they can obtain near-continuous photometry. By contrast, professionals tend to have limited time on much larger telescopes, which is usually scheduled well in advance, but they are able to obtain more detailed astrophysical data and this is often supplemented with multi-wavelength observations from satellites. Therefore, the activities of professionals and amateurs are complementary: working together across our community, both in obtaining the data and analysing it, has been common practice for many years. There exists a mutual trust and desire for understanding these systems that I believe is the key to the success of the collaboration. (continued)

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