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Line Profile Variations in M Giants: Clues to Mass-Loss and Chromospheric Heating Mechanisms
Judge, P. G.; Stencel, R. E.; Cuntz, M. +2 more
Analysis is presented of time-series, high dispersion spectra of the Mg II, k, Ca II H, and K lines of the semiregular giants Rho Per (M4 II-III, periodicity of about 50 days), R Lyr (M5 III, period of about 46 days), and g Her (M6 III, period of about 90 days). The fine error sensor on the IUE satellite and ground based UBV photometry was used to…
Multifrequency Comparison of Cepheids and Nonvariable Supergiants
Evans, Nancy R.; Jiang, Jonathan H.; Campins, Humberto +1 more
New IUE data and infrared J, H, K, L, and M observations have been obtained for nonvariable yellow supergiants and the prototype classical Cepheid Delta Cephei. These data have been combined with data in the literature to make a comparison between nonvariable yellow supergiants and Delta Cephei from the UV through the near-IR. The supergiant seque…
Hubble Space Telescope Observations of the Galactic Center Region at 1.02 Microns
Becklin, E. E.; Liu, T.; Henry, J. P. +1 more
We present HST observations of the galactic center region using the Planetary Camera with the F1042M filter at an effective wavelength of 1.02 micron. We detect several infrared sources seen at this wavelength before but with angular resolution better than previous observations. Our data reveal the source GZ A which was first seen by Rosa et al. (…
What can you Gain From Deconvolution? Observing Faint Galaxies With the Hubble Space Telescope Wide Field Camera
Elson, Rebecca A. W.; Schade, David J.
We describe experiments with deconvolutions of simulations of deep HST Wide Field Camera images containing faint, compact galaxies to determine under what circumstances there is a quantitative advantage to image deconvolution, and explore whether it is (1) helpful for distinguishing between stars and compact galaxies, or between spiral and ellipti…
Internal Ultraviolet Explorer Observations of the white Dwarf Nucleus of the Very Old, Diffuse Planetary Nebula, IW-2
Bruhweiler, F. C.; Feibelman, Walter A.
UV low-dispersion spectra of the central star of the faint planetary nebula, IW-2, were obtained with the IUE. The apparent large diameter of the very diffuse nebula, about half that of the moon, as seen on the Palomar Sky Survey plates by Ishida and Weinberger (1987), indicates this object to be potentially quite evolved, and nearby. The IUE spec…
Silicon Abundances in Population I Giants
Bohm-Vitense, Erika
Silion to carbon abundance ratios for Population I giants were determined from emission lines originating in the transition layers between stellar chromospheres and coronae. For effective temperatures larger than 6200 K we find a group of stars for which the silicon to carbon abundance ratio appears to be increased. These stars are presumably desc…
The Quality of Photometric Information in the HIPPARCOS Input Catalog
Casertano, Stefano; Ratnatunga, Kavan U.; Bell, David J. +1 more
Comparison with independent photoelectric photometry is used to assess the quality of magnitudes and colors in the Hipparcos Input Catalog. These magnitudes and colors will play an important role in the luminosity calibration of Hipparcos stars. We conclude that photoelectric photometry, available for about 37 percent of the catalog, is of uniform…