Pro-Am astronomy: variable stars

Meeting report N early 60 professional and amateur astronomers attended this second Pro-Am meeting, organized by the Royal Astronomical Society and the British Astronomical Association in Cambridge on Saturday 26 January 2002. This meeting followed the successful inaugural RAS/BAA ProAm meeting at Mill Hill in September 2000. The theme for the Cambridge meeting was “Explosive and variable stars”. The meeting was opened formally by Guy Hurst, President of the BAA and editor of The Astronomer. Guy proclaimed the success of the previous meeting and stressed the importance of Pro-Am exchanges in the field of variable stars, emphasizing the continuing requests from professional astronomers for data from amateurs. Then the posters were briefly introduced. Nial Tanvir (Hertfordshire) presented his poster on gamma-ray bursters, mentioning current monitoring from satellites and follow-up programmes that include amateur groups around the world. Gillian Pearce (Wolverhampton) spoke on theoretical modelling of supernovae and the current work in the amateur community, including a request for data to extend light curves. Roger Pickard (BAA Variable Stars Section) reported on work undertaken with the Jack Ells APT. Finally, Andy Hollis (BAA Asteroids and Remote Planets Section) spoke on his CCD and telephoto lens arrangement, describing CCD work on photometry with this most modest of equipment. The morning session was chaired by Nial Tanvir, who introduced Guy Hurst to give the first presentation of the meeting, “Pro-Am cooperation in handling nova and supernovae discovery claims”. Guy described his attempts to examine discovery claims and the correct procedures for reporting a possible suspect, including the problems caused by early (non-confirmed) reporting of discoveries on the internet. He dealt with 283 discovery claims in 2001, compared to 97 in 1987. The majority turned out to be new variable stars. He then described his logging method, which includes allotting a Q number to every alert he receives, then allocating a TAV or August 2002 Vol 43 Gary Poyner and Roger Pickard report on the Joint Royal Astronomical Society/British Astronomy Association Professional-Amateur Meeting on explosive and variable stars held in Cambridge in January 2002. TASV (followed by its J2000.0 position) identification to the object once it has been followed up. This method is approved by the IAU. IAU guidelines for confirming a supernovae were also described in detail, including astrometric positions, a second night’s observation of the suspect, the object found not to be present on earlier images, and spectral confirmation. At least three of these criteria must be met. Finally, Guy stated that he is generally impressed by the quality of reports that he receives. Discoveries and deductions Chris Jones (visual observer, Essex) spoke on “Discovery made easy – investigating the variable stars identified by Mike Collins”. Chris described some of Mike Collins’ incredible discovery statistics, all made photographically and checked by eye – 175 discoveries or recoveries, 32 new variables named in the GCVS, 55 NSVs and another 150+ pending. The majority of stars discovered are Mira stars, very few of which are currently monitored by amateurs. Chris then gave an example of his own work. From early data, the variability of NSV 8001 was little understood, yet a mere 31 months of visual observation showed it to be a Mira star. He then showed light curves of visual observations, and pointed out the problems caused by smallamplitude red variables. Finally, a summary of results for the years 1998–2001 was presented, with a request for more data on these underobserved stars, along with better charting. Albert Zijlstra (UMIST) continued a theme with “Period evolution in Mira variables”. The evolution of Mira and SRc stars was discussed, 4.33 Pro-Am astronomy: variable stars including their fluctuating periods, with R Hya as a case study. The various characteristics of the physical and optical behaviour of Mira and SR stars were discussed and the importance of stellar winds was emphasized. Albert stressed the need for long-base light curves of these stars, in order to study their long-term behaviour – definately a job for the amateur! The 40–50 years of data collected by Albert Jones on W Hya was given as an example of what longterm visual monitoring can achieve: evidence that the variation in period is itself periodic. Again the value of amateur archives was emphasized with T UMi, BH Cru and R Hya listed as examples. Albert went on to describe some of the physical characteristics of SRs and Miras, including data obtained from IRAS. Albert’s final comments were that an amateur database is essential for research into these objects, and that a continuous data-set is vital. The final talk of the morning session was given jointly by Stephen Smart (Cambridge) and Peter Meikle (Imperial) on “The European Supernova Network and discovering nearby supernovae – helping support observing from the Hubble Space Telescope”. Peter Meikle started with a general overview of supernovae. The Supernova Network was then described: 10 institutions in Europe are involved, including 70 professional astronomers and seven major telescopes, with a time span of four years envisaged. The nearest and brightest SNe would be the ideal target, with the amateur role to include fast alerts to new SNe, and frequent observations once one has been detected. These would ideally be undertaken with V-band filters. If confidence is high on a suspect, there will be an over-ride on certain professional instruments in order to obtain early data. Stephen Smart continued with a description of the evolution of SNe, and the search for ideal SNe candidates. This included the origins of SNe types, pre-SNe stars, the life cycle of massive stars and pre-explosion images from the HST archive. The amateur’s role was again discussed, stressing the need for discoveries of SNe brighter than magnitude 16, and the importance of follow-up monitoring. A buffet lunch was followed by a tour of the observatories and telescopes. There was also plenty of time to chat and make contacts, such important elements of a meeting of this nature. The afternoon session was chaired by Roger Pickard, who introduced Peter Wheatley (Leicester) to talk on “Co-ordinated X-ray and optical observations of dwarf novae”. Peter started with an amateur-based light curve for SS Cyg and went on to describe the general behaviour of dwarf novae (DNe), the accreting system and eclipsing DNe. A computergenerated model of an accretion disk in outburst was shown. An eclipse light curve of OY Car in X-rays was shown, showing the disappearance of X-rays during eclipse. Peter also Meeting report More robotic telescopes Continuing this theme, Paul Murdin (Cambridge) then spoke about “The Faulkes Telescope”. This will include two 2 m telescopes for public education. The Northern telescope will be on the (...truncated)