Presentation on theme: "N.N. Samus Institute of Astronomy (Russian Acad. Sci.) Sternberg Astronomical Institute (Moscow University) Eurasian Astronomical Society Activity of the."— Presentation transcript:
N.N. Samus Institute of Astronomy (Russian Acad. Sci.) Sternberg Astronomical Institute (Moscow University) Eurasian Astronomical Society Activity of the IAU Commission 27 working group on the future of the GCVS XXVII General Assembly of the IAU Rio de Janeiro, August 2009
The working group was created at the Prague IAU. On November 16, 2006, I got a message from Steve Kawaler with the following information: “…The Commission 27 SOC is working on a ‘charge’ to the WG to help clarify what the problems are and what specific questions the WG might want to investigate. Hopefully we’ll converge on a charge wording, and then can distribute that to the Commission members and enlist people to help with the work of the WG.’’ I never heard from Steve on this topic again; maybe some messages went astray. So we proceeded according to our own understanding of the problems.
Rio de Janeiro, August 2009 A web page was created on the problems of the WG
Rio de Janeiro, August 2009 In my understanding, the main questions for our consideration are: What is the future of the GCVS? Should the project be continued? If yes, what should its future scope be? How should the GCVS interact with large catalogs of new variables from automatic surveys? How should it interact with the VSX and SIMBAD? Should we try to standardize information these sources provide for variable stars? Unfortunately, we received a very limited response either from WG members or from other members of the variable-star community concerning the topics of the WG. The main contributions were: Several suggestions by Laszlo Szabados concerning classification of anomalous Cepheids and dwarf Novae A paper by C. Simon Jeffery (IBVS No. 5817, 2008) on classification of extreme helium stars (several types suggested for a dozen of stars)
Rio de Janeiro, August 2009 The GCVS team attempted to begin test-mode practical application of the classification scheme we suggested in Prague. So far, it has been done for all GCVS stars in six constellations (Andromeda, Antlia, Aquarius, Ara, Aries, Telescopius); for three of them, a paper with new classifications published (Peremennye Zvezdy (Variable Stars) 27, No. 6, 2007). The 79th Name-List of Variable Stars has been prepared as a full-GCVS-format catalog with two versions of the classification, traditional and experimental one (accepted to Astronomy Reports, 2009).
Rio de Janeiro, August 2009 In April 2009, the Director of the AAVSO Dr. Arne Henden (an active member of the WG) invited me to the AAVSO Headquarters (Cambridge, MA) to discuss problems of variable-star catalogs. The AAVSO wants to make the VSX “the main entry point to the GCVS system”. Samus joined the team of VSX moderators.
Rio de Janeiro, August 2009 We started a serious attempt of coordinating the content of the GCVS and VSX. All significant differences in the coordinates have been checked and removed, with a number of serious mistakes found in both facilities. We jointly contacted the SIMBAD data base and suggested to join us. Since then, the SIMBAD team has contacted us a number of times in order to remove discrepancies in variable-star coordinates between SIMBAD and the GCVS. One future goal for the AAVSO will be to collaborate with the GCVS team to improve the information for all poorly studied stars in the GCVS. Type classification of variable stars is a difficult subject with no current resolution. The AAVSO and GCVS teams suggested that a report be made to Commission 27 that the working group be continued until a solution is found.
Rio de Janeiro, August 2009 Preliminary answers to the questions above: The GCVS work should be continued, with the main task to improve information provided for “old” variable stars, to transfer stars from the NSV catalog to the GCVS using modern possibilities Stars from automatic surveys will be added to the GCVS if they meet GCVS criteria on accuracy of coordinates and quality of classification. Large lists can be added using help from the AAVSO All units engaged in projects related to catalogs of variable stars are overloaded with work. The old star-by-star approach cannot be continued for any long period of time. Radical decisions are possible in future (like a time deadline for GCVS naming) Classification seems to be an unsolved problem that is not of the first importance. We will continue to apply the experimental system, continuously thinking how to further simplify it. Those who object to the experimental system are asked to let the GCVS team know.