Messenger No. 36 (June 1984)
Please be informed that ESO-Chile has a new postal address:
The Space Telescope European Coordinating Facility Begins its Activity
As announced in the Messenger No. 31, on the 23rd of February 1983, the Directors General of the European Southern Observatory and of the European Space Agency signed the Agreement concerning the establishment of the Space Telescope European Coordinating Facility (ST-ECF). One year later, on the 1st of March 1984, the ST-ECF began its activity on the ESO premises in Garching.
Progress in High Resolution Spectroscopy Using a Fibreoptic Coude Link
Lund, G.; Ferlet, R.
AA(ESO) AB(Institut d'Astrophysique, Paris)
Experiments with a prototype 40 m optical fibre link between the 3.6 m telescope and the CES have already been described in the Messenger No. 31, and by Lund and Enard (1983). Further tests of this system, carried out in February 1984 using slightly different optical fibres and a highly efficient image-slicer, have confirmed the usefulness of a fibre link as an alternative to a 4-mirror coude train. Gains in sensitivity typically of the order of 1.5 magnitudes in comparison with the c1assical CAT-slit-CES combination were obtained, thus permitting for the first time good spectra of 11 th magnitude objects to be achieved with aresolution of 80,000.
Gillet, D., and Ferlet, R. 1983. Astron. Astrophys. 128, 384.
Lund, G., and Enard, D. 1983, Proc. SPIE 445, "Instrumentation in
Astronomy V", 65.
Tentative Time-table of Council Sessions and Committee Meetings in 1984
Spectroscopy of late type giant stars
Spaenhauer, A.; Thevenin, F.
AA(Basel, Universitaet, Basel, Switzerland), AB(Paris, Observatoire, Meudon, Hauts-de-Seine, France)
An attempt to calibrate broadband RGU colors of late type giant stars in terms of the physical parameters of the objects is reported. The parameters comprise the effective temperature, surface gravity and global metal abundance with respect to the sun. A selection of 21 giant star candidates in the Basel fields Plaut 1, Centaurus III and near HD 95540 were examined to obtain a two color plot. Attention is focused on the G-R color range 1.5-2.15 mag, i.e., spectral types K0-K5. A relationship between R and the metallicity is quantified and shown to have a correlation coefficient of 0.93. No correlation is found between metallicity and gravity or R and the effective temperature.
Becker, W. 1972: Quarterly Journal Roy. Astron. Soc. 13,226.
Becker, W., Fang, Ch. 1973: Astron. Astrophys. 95, 184.
Becker, W., Hassan, S. 1982: Astron. Astrophys. Suppl. 47,247.
Bond, H. E. 1980: Astrophys. J. Suppl. 44, 517.
Buser, R. 1977: Astron. Astrophys. 62, 411.
Hawkins, M. R. S. 1984: Monthly Notices of the Royal Astronomical
Spaenhauer, A, Fenkart, R. P., Becker, W. 1982: Mitt. Astron. Ges. 57,
Spaenhauer, A, Fang, Ch. 1983: Astron. Astrophys. Suppl. 47,441.
Spaenhauer, A, Topaktas, L., Fenkart, R.P. 1983: Astron. Astrophys.
Thevenin, F., Foy, R. 1983: Astron. Astrophys. 122, 261.
Thevenin, F., Spaenhauer, A, Foy, R. 1983: Astron. Astrophys. 124,
Wildey, R. L., Burbidge, E. M., Sandage, AR., Burbidge, G. R. 1962:
Astrophys. J. 135, 94.
Deep photometry of far globular clusters
Ortolani, S.; Gratton, R.
AA(Osservatorio Astrofisico, Asiago, Italy), AB(Osservatorio Astrofisico, Asiago, Italy)
The results of a photometric survey of distant and giant globular clusters in the galactic halo are described. About 50 frames in the B and V ranges were obtained in four nights in January 1983. Acceptable imagery of Am-1, Pal 3 and GLC 0423-21 were obtained with good accuracy down to 22 mag. Metal-poor, inner halo clusters exhibited a higher blue HB star population than metal-rich globular clusters with more red stars. It is estimated that the clusters are 100 kpc from the sun.
Comet p / Crommelin 1983N
Danks, A. C.
Comet Crommelin has aperiod of approximately 27.4 years and consequently a well-studied orbit. It has an orbital excentricity e = 0.92, taking Crommelin on its excursions through the solar system out to a distance of 9.09 AU and in to a perihel ion distance of approximately 0.73 AU. The precise orbit details are given in IAU circular No. 3886. A comet's predicted brightness is unreliable, a function of distance from the sun, earth and albedo and naturally it is the albedo which is poorly known. But predictions for a comet with many previous passages are more reliable and the integrated visual brightness of Crommelin was predicted to be in the order of 7 to 11. It was recognized that Crommelin would serve nicely as a test object for the International Halley Watch network (IHW), i. e. its participating observers, equipment and data compatibility. Obviously the closer the comet to the sun the brighter it becomes but of course the more it moves into day. It is usual then when the comet is brightest to catch it either in the early morning as it rises before the sun, or just above the horizon in the early evening after the sun has set.
International Halley Watch Spectroscopy and Spectrophotometry
Bulletin No. 1 (1984).
The Pickering-Racine wedge with the triplet corrector at the ESO 3.6 M telescope
Alcaino, G.; Liller, W.
AA(Ministerio de Educacion de Chile, Instituto Issac Newton, Santiago, Chile), AB(Ministerio de Educacion de Chile, Instituto Issac Newton, Santiago, Chile)
The physical set-up, capabilities and applications of a slightly deviated glass wedge at the entrance beam of the ESO 3.6 m telescope are described. The wedge produces a faint secondary image by the primary image of a bright star and thereby increases magnitude resolution on photographic plates. The 3.6 m instrument field diameter has been augmented to 1.0 deg by the addition of a triple corrector for the wedge, which can be automatically moved in and out of the picture and produces a 14 arcsec separation between the images with about a 4 mag difference. A sample plate is provided of the globular cluster 47 Tucanae.
Blanco, V.M., 1982. P.A.S.P. 94, 201.
Christian, C.A., and Racine, R., 1983. P.A.S.P. 95, 457.
Pickering, E. C., 1891. Ann. Astr. Obs. Harvard, 26, 14.
Racine, R., 1969. Astron. J. 74, 1073.
Racine, R., 1971. Astrophys. J. 168, 393.
Finding carbon stars in nearby galaxies
Azzopardi, M.; Westerlund, B. E.
AA(European Southern Observatory, Garching, West Germany), AB(Astronomiska Observatoriet, Uppsala, Sweden)
The serendipitous discovery of several carbon stars in the Magellanic Clouds while a survey of WR stars was being performed led to initiation of a search for other carbon stars in Local Group galaxies. Carbon stars are known to have a C/O ratio higher than unity and are members of the asymptotic giant branch (AGB), i.e., possess a shell structure consisting of a degenerate C-O nucleus, a radiative He layer and a convective hydrogen envelope. No oxides (except CO) are observed in carbon stars. The survey is being carried out at the CN bands 7945, 8125 and 8320 A. The survey has thus far found carbon stars in the Smaller Magellanic Cloud and the dwarf galaxies Sculptor, Fornax, Leo I and Leo II.
List of Preprints Published at ESO Scientific Group (March - May 1984)
315. W. Eichendorf and J.-L. Nieto: The Central Region of NGC 1510. Astronomy and Astrophysics. March 1984.
A Catalogue of Dark Nebulae for the Southern Hemisphere
Feitzinger, J. V.; Stuwe, J. A.
AA(Astronomisches Institut, Ruhr-Universität, Bochum) AB(Astronomisches Institut, Ruhr-Universität, Bochum)
A catalogue of dark nebulae and globules has been compiled from a study of the ESO (B) and SRC J Sky Atlas for galactic longitudes 240° < l < 360°. This catalogue closes the great southern gap open since the work of Lynds (1962) for the northern hemisphere. To secure utmost consistency and comparability between both surveys we followed as closely as possible Lynd's method in searching, determining and describing the dark nebulae.
B.T. Lynds, 1962, Ap. J. Suppt. 7, 1.
S. van den Bergh, 1972, Vistas 13, 265
The chemical enrichment of galaxies
AA(European Southern Observatory, Garching, West Germany)
The production rates of certain chemical elements per stellar generation and the effect of Fe production from intermediate mass stars on the chemical evolutions of the solar neighborhood are considered. Attention is given to the He-4, C-12, C-13, O-16, N-14 and Fe-56 added to the interstellar medium (ISM) per stellar generation. Lower mass elements are produced in low mass stars, intermediate mass stars produce all contributed elements, and high mass stars are a major contributor of heavy elements. Comparisons of the observed ISM abundances with different elemental evolution scenarios are noted to aid in confirming stellar evolution models. A calculated variation of the Fe abundance with time is shown to agree well with an age-metallicity relationship for solar neighborhood stars. Finally, the supernova events from the destruction of C-O core stars are also expected to yield heavy nuclei.
Arnett, D. W., 1978, Ap. J. 219, 1008.
Branch, D., 1980, in Type I Supernovae, Ed. J.C. Wheeler, Austin.
Iben, I. jr., Renzini, A, 1983, Ann. Rev. Astron. Astrophys. 21,271.
Iben, I., Tutukov, A., 1983, in Stellar Nucleosynthesis, Erice workshop,
Ed. C. Chiosi, A. Renzini, Reidel Publ. Comp., in press.
Maeder, A, 1981, Astron. Astrophys. 101,385.
Maeder, A, 1983, in Primordial Helium, ESO workshop, Ed. S.
D'Odorico, D. Baade, K. Kjär, p. 89.
Nomoto, K., 1983, in Stellar Nucleosynthesis, Erice workshop, Ed. C.
Chiosi, A. Renzini, Reidel Publ. Comp. in press.
Reimers, D., 1975, Mem. Soc. Roy. Sci. Liege, 6 Sero 8, 369.
Renzini, A., Voli, M., 1981, Astron. Astrophys. 97, 175.
Salpeter, E.E., 1955, Ap. J. 121,161.
Tornambe, A, 1984, in Population Synthesis, Frascati workshop,
Ed. V. Caloi, V. Castellani, Mem. Soc. Astron. 11., in press.
Twarog, BA, 1980, Ap. J. 242, 242.
Woosley, S. E., Weaver, T.A, 1983, in Supernovae: A Survey of
Current Research, Ed. M.J. Rees, R.J. Stonehan, Reidel Publ.
Comp., p. 79.
Stellar seismology - Five-minute P modes detected on Alpha Centauri
Fossat, E.; Grec, G.; Gelly, B.; Decanini, Y.
AA(Nice, Observatoire, Nice, France), AB(Nice, Universite, Nice, France), AC(Nice, Universite, Nice, France), AD(Nice, Universite, Nice, France)
A spectrophotometer was devised for detecting seismic disturbances in stellar sources. Based on the principle of optical resonance spectroscopy, the instrument is capable of 1/msec oscillation amplitude Doppler shift measurements. Twenty hours of data on Alpha Centauri covered the monochromatic intensity in the red wings of Na D1 and D2 lines and a 20 A passband of an interference prefilter used in a reference channel. Steps were taken to account for atmospheric interference and determine the harmonics using Fourier analysis. An 81.3 micro-Hz period was observed for a 2.3-3.8 mHz periodicity in the power spectrum, a result that is similar to a period detected in the Sun, thereby indicating that a 5 min p-mode may also be occurring in Alpha Centauri.
Claverie, A., Isaak, G. R., Me Leod, C. P., Van der Raay, H. E., Palle,
P. L., and Roea Cortes, T. 1984, Proeeedings 01 the EPS Catania
Deubner, F. L. 1975 Astron. Astrophys. 44, 371.
Fossat, E., Deeanini, Y. and Gree, G. 1982, Instrumentation for
Astronomy with large telescopes, C. Humphries, ed. September
Fossat, E., Deeanini, Y., and Gree, G. 1983, The Messenger, 33,29.
Gough, D. O. 1984, preprint.
Gree, G., Fossat, E. and Pomerantz, M. 1983, Solar Phys. 82,55.
Leighton, R. 1960, IAU Symposium n° 12 (Nuovo Cimento Suppl. 22,
A Close Look at Our Closest Neighbor - High Resolution Spectroscopy of Alpha-Centauri
Soderblom, D. R.
AA(Harvard-Smithsonian Center for Astrophysics, Cambridge MA, USA)
As most astronomers will tell you, most of the telescopes are in the northern hemisphere, and most of the interesting objects are in the south. The Magellanic Clouds, the largest globular clusters, and the center of our Galaxy are among the celestial objects that must be studied fram south of the equator. Also in the deep south are the Sun's nearest neighbors - the a Centauri system. It contains three stars: (1) a Cen A has the same spectral type as the Sun, although it is slightly more massive; (2) a Cen B is a little less massive than the Sun and orbits a Cen A with aperiod of 80 years; and (3) Proxima Cen is a very low mass star that is slightly closer to us than either of the other two. Praxima Cen is moving through space in the same direction and at the same rate as a Cen A and B, but is very distant from them.
CA II in HD 190073 Revisited
Ringuelet, A. E.; Sahade, J.
AA(Instituto de Astronomia, Buenos Aires, Argentina) AB(Instituto Argentino de Radioastronomia, Villa Elisa, Argentina)
In 1933, Paul W. Merrill, of the Mount Wilson Observatory, Published, with the collaboration of Cora Burweil (Merrill and BurweIl, 1933), a Catalogue of such attractive objects as the Band Astars that display emission lines in their spectra. The classical model for the Be stars suggests that we are dealing with evolved (off the main sequence) objects and that the emisson arises because of a geometrical effect in the flat, extended envelope that surrounds them. This envelope would result from the shedding of matter through the equatorial bulge because of instability generated by the large rotational velocities that seemed to characterize our group of objects. Such a model is, however, vulnerable in many aspects, as recent studies, particularly those that cover the satellite ultraviolet wavelength region, have disclosed. Indeed, the apparent correlation of rotational velocity and emission is no longer an established fact, the mass loss rate does not seem to be related with velocity of rotation, and it does not seem to be necessarily true that the emission is observed because of a geometrical effect. The investigation of Be.and Ae stars, in as an extended a wavelength range as possible is, therefore, most desirable if we wish to reach a full understanding of their nature and of the structure and extent of their gaseous envelope.
Allen, D.A.: 1973, Monthy Notices Royal Astronomical Society 161,
Babcock, H. W.: 1958, Astrophysical Journal Supplement 3, No. 30.
Dyck, H. M. and Milkey, R. W.: 1972, Publications Astronomical 50-
ciety of the Pacific 84, 597.
Geisel, S. L.: 1970, Astrophysical Journal Letters 161, L 105.
Merrill, P. W. and Burwell, C.G.: 1933, Astrophysical Journal 78, 87.
Ringuelet, A. E., Sahade, J., Rovira, M., Fontenla, J. M. and Kondo, Y.:
1984, Astronomy and Astrophysics 131, 9.
Sitko, M. L., Savage, B.D., and Meade, M. R.: 1981, Astrophysical
Journal 247, 1024.
Surdej, J., and Swings, J.-P.: 1976, Astronomy and Astrophysics 47,
Surdej, J., and Swings, J.-P.: 1977, Astronomy and Astrophysics 54,
Wool!, N.J., Stein, W.A., and Strittmatter, P.A.: 1970, Astronomyand
Astrophysics 9, 252.
Determination of the rotation curve of our Galaxy Observations of distant nebulae
AA(Leiden, Rijksuniversiteit, Sterrewacht, Leiden, Netherlands)
Progress on a project to determine the shape and strength of the gravitational force influencing the motion of material in the Galaxy is discussed. Attention is focused on the 3rd and 4th quadrant, i.e., the outer Galaxy, and the movement of molecular material. The data are gathered by observing H II lines as a tracer to quantify the galactic rotation curve. Photometric measurements are also made of stars located in nebulae which emit lines similar to the H II lines. Unreddened colors are found for the stars, followed by heliocentric distance and thereby the galactocentric distance. Clouds near some of the nebulae have exhibited velocities of up to 77 km/sec and 18 kpc distances from the galactic center. The most distant objects that can be detected are expected to lie at about 20 kpc from the galactic center. Color and luminosity profiles for objects in the 15-20 kpc radii interval have yet to be measured.
Blitz, L., 1979, Astroph. J. Let!. 231, L115
Optical haloes around galaxies
Beck, R.; Dettmar, R.-J.; Wielebinski, R.; Loiseau, N.; Martin, C.; Schnur, G. F. O.
AA(Max-Planck-Institut fuer Radioastronomie, Bonn, West Germany), AB(Max-Planck-Institut fuer Radioastronomie, Bonn, West Germany), AC(Max-Planck-Institut fuer Radioastronomie, Bonn, West Germany), AD(Instituto Argentino de Radioastronomia, Villa Elisa, Buenos Aires, Argentina), AE(Instituto Argentino de Radioastronomia, Villa Elisa, Buenos Aires, Argentina), AF(Bochum, Ruhr-Universitaet, Bochum, West Germany)
The results obtained from CCD and digitizing microdensitometry of nearby galaxies, with attention focused on optical halos, are reported. NGC 55, NGC 253, NGC 4594 (M104) and NGC 4945 were scanned and plates were made in the U, B, R and I color ranges. Photoelectric photometry with an uvgr filter system using 1 m and 50 cm telescopes helped quantify night sky variations and reduce noise. No color gradients were detected in the galaxies, nor was a source identified for the weak light at the fringes of the galaxies. The examination of a larger sample of galaxies is indicated.
Beck, R., Hutschenreiter, G., Wielebinski, R.: 1982, Astron. Astrophys.
Burkhead, M.S.: 1979, in Photometry. Kinematics. Dynamics of
Galaxies. ed. Evans, University of Texas, p. 143.
Jensen, E. B., Thuan, T. X.: 1982, Astrophys. J. Suppl. 50, 421.
Kormendy, J.: 1980, in ESO Workshop on Two Dimensional Photometry. eds. P. Crane and K. Kjär, p. 191.
Malin, D. F.: 1978, Nature 276,591.
Malin, D. F.: 1981, Sky and Telescope 62, 216.
Thuan, Y., Gunn, J. E.: 1976, Publ. Astron. Soc. Pacific 88, 543
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