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Observation of the Spin-forbidden Cameron Bands of CO in the Ultraviolet Emission Spectrum of the Red Rectangle

Sitko, Michael L.; Glinski, Robert J.; Reese, Marty D. +1 more

The center of the biconical nebula known as the Red Rectangle has been observed by using the ultraviolet spectrographs aboard the Hubble Space Telescope. We report the observation of phosphorescence of the Cameron bands of CO (a 3 Pi --> X 1 Sigma +) between 1850 and 2600 A. These bands are seen for the first time outside of the solar system. T…

Two-dimensional Ultraviolet Spectral Typing of O-Type Stars

Gies, Douglas R.; Penny, Laura R.; Bagnuolo, William G., Jr.

We present equivalent-width measurements of ultraviolet photospheric lines that are useful as spectral type criteria; these include 23 lines of He II, C III, N III, N IV, O IV, Si III, Si IV, S V, Fe IV, and Fe V in lUE spectra of 67 O3 to BO stars of all luminosity classes. Seven lines and two line ratios are particularly sensitive to spectral ty…

An O VIII Sequence for Planetary Nebula Nuclei

Feibelman, Walter A.

The detection of O VIII emission lines in ultraviolet and optical spectra of high-excitation planetary nebula central stars suggests an "O VIII Sequence" for these object. Emission lines of O VII are also detected. Seven out of ten central stars for these planetaries are known to be nonradial g-mode pulsators. The stars form a narrow strip when pl…

Hubble Space Telescope Observations of Obscuration Rings in Hercules A: Implications for Energy Transport in Powerful Radio Galaxies

Baum, Stefi A.; O'Dea, Christopher P.; Livio, Mario +4 more

We have used the Hubble Space Telescope to obtain snapshot images of Hercules A, the host galaxy to the powerful radio source 3C 348, through a broadband red filter. We report the discovery of interlocking, kiloparsec-scale rings of obscuration aligned near the radio axis and slightly offset from the galaxy's nucleus. We discuss possible models fo…

A Grid of Model Atmospheres and Synthetic Spectra for the Far-Ultraviolet Analysis of Old Stellar Populations

Ferguson, Henry C.; Brown, Thomas M.; Davidsen, Arthur F.

We present a grid of stellar synthetic spectra suitable for detailed comparison to far-ultraviolet (FUV) observations obtained with the Hopkins Ultraviolet Telescope, IUE, and HST. Our specific application is to study the hot stellar populations in elliptical galaxies, but we anticipate that the models will be useful for other purposes. The 1,497 …

ISO observations of the classical nova V1974 Cygni.

Kessler, M. F.; Eyres, S. P. S.; Salama, A. +3 more

We present observations of the classical nova V1974 Cygni (Nova Cyg 1992) obtained with the ISO Short and Long Wavelength Spectrometers (SWS and LWS) and the spectrometer section of ISOPHOT. We identify [NeIII]λ15.5, [NeV]λ14.3, 24.3, [NeVI]λ7.6, [OIII]λ51.8, [OIV]λ25.9. There is evidence that the Ne and O emission arises in physically distinct re…

Globular Cluster Luminosity Functions and the Hubble Constant From WFPC Imaging: Galaxies in the Coma I Cloud

Forbes, Duncan A.

The membership of some galaxies in the nearby (d ~ 12 Mpc) Coma I cloud is uncertain. Here we present globular cluster luminosity functions (GCLFs) from the Hubble Space Telescope for two bright ellipticals which may belong to this group. After fitting the GCLF, we find a turnover magnitude of m_V_^0^ = 23.23 +/- 0.11 for NGC 4278 and m_V_^0^ = 23…

Searching for coronal plumes in ULYSSES observations of the far solar wind.

Livi, S.; Balogh, A.; Parenti, S. +4 more

In the past, from the analysis of data acquired by the Helios spacecrafts within distances <=1AU, some evidence has been found of the presence of coronal plumes in the solar wind. Ulysses observations offer a unique opportunity to search for plume remnants in the polar wind at larger distances. Pressure balanced structures (PBS), which might po…

First results from the ISOCAM parallel mode.

Altieri, B.; Kessler, M. F.; Prusti, T. +15 more

We present first results of a survey being made in a broad-band 6.75µm filter using the ISOCAM infrared camera in its parallel mode at ~6" resolution. So far we have analysed a sky area of ~1.375deg^2^ down to a limiting flux of 5 mJy and detected a total of 287 objects. The final survey will cover a sky area of ~33deg^2^, most of which will…

Spectroscopic binary orbits from ultraviolet radial velocities. Paper 21: HD 152248

Stickland, D. J.; Lloyd, C.; Gies, D. R. +2 more