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The WC10 central stars CPD-56 deg8032 and He 2-113 - I. Distances and nebular parameters
Barlow, M. J.; De Marco, Orsola; Storey, P. J.
We present the results of an analysis of the WC10 central stars CPD-56 deg8032 and He 2-113 and of their surrounding planetary nebulae (PNe). UCL Echelle Spectrograph spectra with a resolving power of R=50 000, covering the wavelength range 3600-9500 A, were obtained for both objects. Expansion and radial velocities are derived from the nebular Ba…
Calibration of the Surface Brightness Fluctuation Method for use with the Hubble Space Telescope.
Lauer, Tod R.; Ajhar, Edward A.; Dressler, Alan +4 more
This paper presents the calibration of the surface brightness fluctuation (SBF) technique for use with the Wide Field and Planetary Camera-2 (WFPC-2) on the Hubble Space Telescope (HST). The calibration has a color term and zeropoint significantly different from the Kron-Cousins I-band SBF technique developed for ground-based observations. It is a…
Optical Spectroscopy of EZ Canis Majoris: Indication for Large-Scale Structures in a Wolf-Rayet Wind
St-Louis, Nicole; Morel, Thierry; Marchenko, Sergey V.
We have carried out optical spectroscopy of the Wolf-Rayet star EZ CMa during 20 consecutive nights in 1995 January in support of the IUE Mega-project. In parallel with this optical spectroscopy, we also monitored EZ CMa using narrowband photometry. The light curve was found to be remarkably stable when folded with the \Pscr=3.77 day period, and i…
A Massive Cluster of Galaxies at Z = 0.996
Dickinson, M.; Le Fèvre, O.; Crampton, David +1 more
We report the identification of a cluster of galaxies around the high-redshift radio galaxy 3CR 184 at z = 0.996. The identification is supported by an excess of galaxies observed in projection in I-band images (both in ground-based and Hubble Space Telescope [HST] data), a peak in the redshift distribution comprising 11 galaxies (out of 56 with m…
Hubble Space Telescope Imaging of the Globular Cluster System Around NGC 5846
Forbes, Duncan A.; Brodie, Jean P.; Huchra, John
Bimodal globular cluster metallicity distributions have now been seen in a handful of large ellipticals. Here we report the discovery of a bimodal distribution in the dominant group elliptical NGC 5846, using the Hubble Space Telescope's Wide Field and Planetary Camera 2 (WFPC2). The two peaks are located at V-I=0.96 and 1.17, which roughly corres…
Direct observational evidence for a heliospheric magnetic field with large excursions in latitude
Schwadron, N. A.; Zurbuchen, T. H.; Fisk, L. A.
Fisk has pointed out that the heliospheric magnetic field in fast solar wind, that is, at the higher heliographic latitudes, may undergo large excursions in heliographic latitudes, and thus that the field will deviate from the expected Archimedes spiral pattern. These excursions result from the interplay between the nonradial expansion of the sola…
O Stars in Transition. II. Fundamental Properties and Evolutionary Status of Ofpe/WN9 Stars from HST Ultraviolet Observations
Moffat, Anthony F. J.; Leitherer, Claus; Schmutz, Werner +4 more
We present new HST/FOS ultraviolet spectroscopic observations of seven LMC Ofpe/WN9 stars. We find that Ofpe/WN9 stars have slow winds with terminal velocities of about 400 km s-1 and high mass-loss rates of the order of 2-5 × 10-5 M⊙ yr-1. Ofpe/WN9 stellar temperatures and radii are in the range 30,000-…
The Green Line Corona and Its Relation to the Photospheric Magnetic Field
Michels, D. J.; Schwenn, R.; Howard, R. A. +8 more
Images of the green line corona made with the LASCO C1 coronagraph on SOHO are analyzed by applying current-free extrapolations to the observed photospheric field. The Fe XIV λ5303 emission is shown to be closely related to the underlying photospheric field strength. By modeling the observed intensity patterns as a function of latitude and height …
An ISO Long Wavelength Spectrometer detection of CH in NGC 7027 and an HeH^+ upper limit
Barlow, M. J.; Cernicharo, J.; Liu, X. -W. +10 more
We have detected an emission line at 149.18+/-0.06 µm in the ISO Long Wavelength Spectrometer (LWS) grating spectrum of the planetary nebula NGC 7027. This line coincides in wavelength with both the HeH^+ J=1-0 fundamental pure rotational line at 149.14 µm and the CH ^2Pi_3/2 (F_2) J=3/2-^2Pi_1/2 (F_2) J=1/2 fundamental pure rotational…
White dwarfs observed by the HIPPARCOS satellite.
Koester, D.; Vauclair, G.; Schmidt, H. +1 more
The HIPPARCOS satellite has measured trigonometric parallaxes for 20 white dwarfs. With the exception of one each of the spectral types DZ, DC, DB, DQ, the majority are of spectral type DA. We compare the parallaxes with the most recent ground-based determinations. From a spectroscopic analysis of new optical observations we determine atmospheric …