I.A.U. Commission 30 - Radial Velocities (Vitesses Radiales) Report of Business Meeting held in Kyoto, Japan, 1997 August 21 President: C.D. Scarfe Vice-President: J.B. Hearnshaw Organizing Committee: W.D. Cochran, L.N. da Costa. A.P. Fairall, F.C. Fekel, K.C. Freeeman, M. Mayor, B. Nordstrom, R.P. Stefanik, A.A. Tokovinin. The commission's business meeting began at 14:00. The following items were on the agenda. 1. Report of the president. a. Membership. The commission has lost a senior member by the death of F.C. Bertiau on 1995 December 27. In addition the following have resigned their memberships: M. Azzopardi, L. Balona, H. Eelsalu, N. Martin and L. Oetken. However, the commission welcomed the following new members: B. Garcia (Argentina), Y. Gnedin (Russia), S. Hubrig (Germany), D. Queloz (Switzerland), A. Rastorguev (Russia), G. Scholz (Germany) and S. Udry (Switzerland). And it has proposed that the following non-members of the IAU be named as consultants to the commission: P. Butler (U.S.A.), N. Gorynya (Russia) and G. Marcy (U.S.A.). b. Meetings. During the last three years the commission has lent its support to a variety of scientific meetings, including I.A.U. Symposium 179 on "New Horizons from Multi-Wavelwngth Digital Sky Surveys", held in Baltimore in August 1996, and the meeting in Calgary in June 1995 on the "Origins, Evolution and Destinies of Binary Stars in Clusters", which regrettably the Executive Committee was unable to support. We have also supported the following Joint Discussions at the 1997 General Assembly: (i) J.D.8, "Stellar Evolution in Real Time", (ii) J.D. 11, "Redshift Surveys in the Twenty-First Century", and (iii) J.D. 12, "Electronic Publishing, Now and in the Future". Indeed the proposal for J.D. 11 originated in Commission 30, despite the fact that Commission 28 is listed as its principal sponsor, and most of the work of proposing and arranging that J.D. was done by Drs. Fairall and Huchra, to whom the president expressed gratitude. c. Internal operation of the Commission i) Members' list. In order to facilitate communication between members, it was decided early in the triennium to prepare, and distribute to all, a list of members, with postal addresses, telephone and fax numbers, and electronic mail addresses for as many as possible. Unfortunately there remain about 15 members for whom we have no electronic address. At the suggestion of the vice-president, John Hearnshaw, a code for areas of research interests, developed largely by him, was added to the information for each member, and has proved very useful. ii) The commission has also initiated a procedure for choosing its new officers and organizing committee members that is more democratic than that previously in effect, so as to give members a more obviously direct say in the activities of the commission. Any two members of the commission may nominate candidates, and if an election is needed all members are entitled to vote. iii) Finally the president thanked all those who participated in the activities of the commission over the past three years, including in particular the members of the organizing committee, whose advice and help has been greatly appreciated, and above all John Hearnshaw, who he said had been a superb vice-president, and could be expected to be an outstanding president in the next triennium. 2. Election. Exactly four candidates were nominated to fill the four vacancies on the Organizing Committee, so no election was necessary. However two members were nominated for the post of vice-president, necessitating an election. The president announced the result of that election: A.A. Tokovinin 19 votes A.P. Fairall 18 votes Thus the new officers and organizing coimmittee for 1997 to 2000 will be President: J.B. Hearnshaw Vice-president: A.A. Tokovinin Organizing Committee: a. Continuing members: W.D. Cochran, F.C. Fekel, B. Nordstrom, R.P. Stefanik b. New members: T. Mazeh, N. Morell, H. Quintana, S. Udry The president thanked all candidates for their willingness to serve. 3. Galaxy radial-velocity catalogues. A.P. Fairall summarized the current situation, noting the existence of the following five major data bases. a. NASA/IPAC Extragalactic Database (NED), maintained by H. Corwin, B. Madore et al., which currently includes about 770,000 extragalactic objects, of which over 100,000 have referenced redshifts. About 50,000 redshifts include detailed information on instrumentation, measurement and reduction. Conversion is available between geocentric, heliocentric and 3K background reference frames or between user-defined reference frames. b. Lyon Extragalactic Database (LEDA), maintained by G. Paturel et al., for which no current details were available. c. Strasbourg Data Centre (SIMBAD). d. Harvard-Smithsonian Center for Astrophysics Catalog (ZCAT), maintained by J. Huchra et al., which currently includes 91022 entries, including 87904 galaxies with velocities, 74255 of which are published. e. Southern Redshift Catalogue (SRC), maintained by A. Fairall, which includes all measures published for each galaxy, noting any large differences. Dr. Fairall recommended that the commission include in its report a reminder to those publishing redshift data to provide information necessary for users of those data, and the commission agreed to do so, with the following statement: "Commission 30 urges all those who publish radial velocities of galaxies to publish `heliocentric' velocities; if another frame of reference is used, this should be clearly indicated. The velocities should be expressed as cz (i.e. without relativistic correction). Accurate co-ordinates should also be provided." 4. Stellar radial velocity catalogues. H. Levato is the leader of a group in Argentina who have taken over responsibility for maintaining a record of, and publishing information on, work on stellar radial velocities, as successors to the group at Marseille led for twenty years by M. Barbier, who has recently retired. Dr. Levato presented the following progress report. The Argentine group have continued with the compilation of a bibliography for papers that contain radial velocities of stars. Up to 1970 the compilation was made by Abt and Biggs and from 1970 to 1990 by M. Barbier. The work has been continued, looking for papers with radial velocity measures since January 1st, 1991. The period 1991-1994 is already complete, with more than 13,000 new objects added, and the catalogue has been deposited at the CDS. The CDS will add other data for the stars, such as magnitudes, spectral types, positions, etc. The period 1995-1996 is 80% complete and the first semester of 1997 is 40% complete. Papers with radial velocity data have been sought in all the major journals: ApJ, ApJS, A&A, A&AS, PASP, MNRAS, AJ, Rev. Mex. Astron. Astrofis., The Observatory, and around a dozen more. The catalogue shows the radial velocity published by the authors in the case of one measure per star or the average for several measurements if the authors published it. Also indicated are the cases of relative velocities or Coravel velocities, and other unusual details of some kinds of measurements. It is hoped that the catalogue will be available to all users at the CDS as soon as possible. The data for 1995-1996 will be ready by the end of 1997. In the future it is planned to send new material to the CDS about every six months. 5. Standard-velocity stars. R. Stefanik, who chairs the commission's Working Group on Radial Velocity Standards gave a review and progress report on the efforts of that Working Group. For some time it has been known that the official list of IAU radial velocity standards (J. Pearce, Trans. IAU, 9, 441, 1955; R. Bouigue, Trans. IAU, 15A, 409, 1973.) included velocity variables, and that the velocities were not on an absolute or even common velocity system. An observational campaign involving the Dominion Astrophysical Observatory, the Geneva Observatory and the Harvard-Smithsonian Center for Astrophysics was initiated to address this problem. The objective was to establish a new set of late-type IAU radial velocity standard stars with individual mean velocities and an absolute zero point of the system good to 100 m/s. The initial results of this campaign were presented in Trans. IAU, 21B, 269, 1991. Nine stars were eliminated from the IAU list because they showed significant velocity variations of over 1 km/s. However, there was a color dependence of the zero point comparison between the observatories. Work has continued at the three observatories to refine the sample further, and to address the color dependence problem. More than 10,000 observations covering a time span approaching two decades, and in a few cases longer, have been obtained. a. This monitoring shows that the following stars should be eliminated as velocity standards: HD 29587 (SB1, P=1483d, K=1.00 km/s); HD 42397 (a double- line spectroscopic binary of long but unknown period); HD 114762 (SB1, P=84d, K=0.60 km/s); HD 123782 (Pulsation variable, P=494d, K=0.95 km/s); HD 140913 (SB1, P=148d, K=1.83 km/s) and HD 171232 (Long period SB1 with a 4 km/s velocity decrease during the past 14 years). b. As a step toward establishing an absolute zero point to the velocity system the Center for Astrophysics has been monitoring the velocities of minor planets. An absolute system is defined by minor planet velocities, computed from astrometric obits by the Minor Planet Center and good to several tens of mm/s. The offset of the CfA system from this absolute system is -95 +/- 18 m/s with no trends in the residuals with time, declination, hour angle, air mass, or signal-to-noise. This comparison covers eight years with over 800 observations of 25 minor planets. c. The color dependence in the comparison of velocities from the three observatories continues to be an unresolved problem. There does not appear to be a color dependence for solar type stars with B-V between 0.5 and 0.8. The combined mean data from CfA and DAO do not show any color dependence or a difference in zero-point between the bright and faint groups of standards. However, the differences between CfA+DAO and the mean velocities from CORAVEL are correlated with the color indices of the stars, becoming increasingly negative for redder stars. Toward resolving this problem the standard stars are being reobserved by the Geneva team using ELODIE for comparison with the CORAVEL results. d. Little additional progress has been made in establishing a list of early spectral type standard velocity stars from that reported in Trans. IAU, 21B, 269, 1991. Fekel continues to monitor the early type standard candidates at KPNO. He reports that the following stars are variable or probably variable and should be removed from the candidate list: HD 145570 (HR 6031), HD 147394 (HR6092), HD 179761 (HR 7287) and HD 196426 (HR 7878). In response to a question by J.B. Hearnshaw, Dr. Stefanik indicated that the absolute accuracy of the standard star system is probably about 100 m/s. 6. Meeting proposal. J.B. Hearnshaw reported on the proposal for an IAU Symposium on Precise Stellar Radial Velocities, that he had sent to the Assistant General Secretary in November 1996. The proposal is for a meeting in Victoria, Canada, from June 21 to June 26, 1998. The major purpose of the meeting is to explore the various applications of highly precise velocity data. The scope will therefore be broad, and will include such topics as stellar pulsation and line asymmetry, as well as the search for extrasolar planets. The Scientific Organizing Committee (SOC) will be chaired by J.B. Hearnshaw, and the Local Organizing Committee (LOC) by C.D. Scarfe. Further information can be found at the World Wide Web site http://astrowww.phys.uvic.ca/prvs/prvs.html that has been set up by the LOC. (Subsequent to this meeting, the proposal was accepted by the Executive Committee not as a Symposium, but a Colloquium, numbered 170 in the IAU's series.) 7. There being no further business, the meeting adjourned at 15:45.