Congresso del Dipartimento di Fisica Highlights in Physics 2005

1. Congresso del Dipartimento di Fisica Highlights in Physics 2005 11–14 October 2005, Dipartimento di Fisica, Università di Milano Catalogue of Apparent Diameters and AbsoluteRadii of Stars ( CADARS ) – 4th edition A.L.Ciapi*, S.Motta†, and L.E.Pasinetti* * Dipartimento di Fisica, Università di Milano † MIUR SIM 3 0.3 10 visible Databases are an essential tool for the modern Astrophysical research. The need for archiving astronomical data was stressed also by the resolution A3 at the 23rd International Astronomical Union (IAU )General Assembly ( KYOTO,1997). (See box) Over the years the role of Astronomical Data Centres has become more and more important. The international and the major national and local data centres are the repositories for thousands of catalogues of astronomical objects and their fundamental parameters derived from ground based and space observations. The Centres give also many data tables from journal articles. In order to serve different geographical communities optimally , well mantained copies of frequently requested data ( like those of the Hubble Space Telescope ) reside at more than one centre. IAU RESOLUTION A3 ON THE NEED FOR ARCHIVING ASTRONOMICAL DATA Proposed by Commission 5 The XXIIIrd International Astronomical Union General Assembly, Considering the continuing important role of astronomical data from the past, including bibliographical information, Considering the phenomenal increase in these data, Considering the importance of their safeguarding and of their accessibility to the entire astronomical community, recommends that the archiving of these data be an integral part of all major research projects and be taken into account by the editors of journals. The IAU recommends that astronomy archives be coded in the FITS format, supports supports the continued maintenance of the Data Centers whose role in the distribution of information is of prime importance for astronomy, and supports their collaboration. The first world-wide astronomical data centre was the “ Centre des Données Astronomiques de Strasbourg” ( CDS ) which collaborates with IAU Commission 5 – Documentation and astronomical Data and withCODATA ( Committee on Data for Science and Technology of the International Council of Scientific Unions). (http://www.codata.org/ ) For some decades its staff has maintained the database SIMBAD (http://cdsweb.u-strasbg.fr/Simbad.html ) of fundamental astronomical data and bibliographical information on, generally , galactic, non- solar- sistem objects. The CDS also develops and mantains the VizieR catalogues browser, which provides access to more than 2,500 catalogues and observation logs. Another CDS-tool is the ALADIN interactive sky-atlas, which allows one to overly SIMBAD, NED, catalogues and observation -logs on images of different origins, some of which are stored at the CDS, some others in observatory archives. The extragalactic counterpart to the CDS is NED , the NASA/IPAC Extragalactic Database ( see box ). A number of local or national institutes host collections of catalogues or support data centres which are of great importance regionally or even world-wide. Examples are the Inter-University Centre for Astronomy and Astrophysics , Ganeshkind, India, the centre at La Plata Observatory Argentina ,and the Canadian Astronomical Data Centre (CADC ) at the Dominion Astrophysical Observatory, Victoria, BC ( see box). The CADC is one of the world’s distribution centres for data from the Hubble Space Telescope Archive. The Centre collaborates with European Southern Observatory and Space Telescope European Coordinating Facilities ( ST-ECF) in maintaining the necessary software . Last generation interferometers Some of the most important Astronomical Data Centresand Databases Centre de Données astronomiques de Strasbourg (CDS) ( http://cdsweb.u-strasbg.fr/ ) National Astronomical Observatory of Japan / Astronomical Data Analysis Center ( http://dbc.nao.ac.jp/ ) The Canadian Astronomy Data Centre (CADC/CCDA) ( http://cadcwww.dao.nrc.ca/ ) Centre of Astronomical Data (Russia) ( http://nut.inasan.rssi/ru/ ) NASA's High Energy Astrophysics Science Archive Research Center (HEASARC) ( http://heasarc.gsfc.nasa.gov/ ) NASA/IPAC Extragalactic Database (NED) ( http://nedwww.ipac.calteck.edu/ ) CHARA ARRAY CADARS from the “Centre Des Données Astronomiques de Strasbourg” ( CDS ) KECK TWIN TELESCOPES On invitation of CDS and IAU Comm.5, a “ Catalogue of Apparent Diameters and Absolute Radii of Stars ( CADARS)” determinated by different methods and technologies was planned in 1979 ( I ) and published in 1981 (2) e (3) :CDS Catalogue II/61. The second edition ( CDS Catalogue II/155 ) (4) e (5) is included in the CD ROM of the NASA (6),reporting the most frequently requested catalogues.CADARS is used by the scientific community both for studies on stellar structure and evolution, and calibrations of stellar instruments. The authors were encouraged to assemble a 3rd edition (CDS Cat II/224) updating the catalogue with the large amount of high precision data from the long baseline interferometers ( 7 ). SIM ( Space Interferometry Mission ) At present we are implementing and updating the 4th edition of the CADARS. Statistical researches are in progress on the catalogue, as well as comparison and calibrations of the different methods used for the determination of the parameters. We note that , at present, most of the data are derived from direct measures rather than from indirected methods as in the previous editions. As example of the evolution of this type of measures we give two statistical histograms reporting the number of stars versus the magnitude. Indirect methods are based on the observations of some physical parameters indirectly correlated with the geometry of the stellar disk by means of models. Direct methods are based on the observation of some physical phenomena directly correlated with the geometry of the stellar disk: interferometric measurements, occultations, pulsating stars, eclipsing and spectroscopic binaries. Current and Future Optical Interferometers (adapted from J.D.Monnier “ Optical Interferometry in Astronomy”, Reports on Progress in Physics, vol 66, p.789, 2003 ) Statistical histograms from the CADARS The differences in these histograms for some methods are due also to the limiting magnitude of the basic data, as in the case of Fracassini Pasinetti method based on the Geneva Photometric Catalogue (ref.Fracassini,M., Gilardoni,G.,Pasinetti,L.E. 1973,Astrophysics and Space Science, 22,141 ) • References • Fracassini M., and Pasinetti L.E.,Bull.Inf. CDS, 16, 49 (1979) • Fracassini M, Pasinetti L.E., and Manzolini F., “Catalogue of apparent diameters and • absolute radii of stars (CADARS) Astron. Astrophys.Suppl.Ser.45, 145 (1981) • Fracassini M., Manzolini F. and Pasinetti L.E., “Preliminary Comments on the Catalogue • of Apparent Diameters and Absolute Radii of Stars (CADARS) Astron. Astrophys. Suppl. • Ser. 44, 55 (1981 ) • Fracassini M., Pasinetti Fracassini L.E.,and Pastori L., Bull. Inf. CDS, 35, 121 (1988) • Pastori L., Pasinetti L.E., and Pironi R.,Bull. Inf. CDS, 35, 69 (1988 ) • Gail L., “Selected Astronomical Catalogs”, Volume 2, ADC-NASA (1996 ) • Pasinetti Fracassini L.E., Pastori L., Covino S., and Pozzi A., “ Catalogue of Apparent • Diameters and Absolute Radii of Stars (CADARS)- Third edition-Comments and • Statistics “ Astron. Astropphys.367, 521 (2001) SIM Space Interferometry Mission NASA-JPL Earth trailing solar orbit 2011