Publications of the Astronomical Society of the Pacific

Ebbets, D. C.; Brandt, J. C.

doi: 10.1086/131205pmid: N/A

The High Resolution Spectrograph is one of five scientific instruments which will be part of the Space Telescope observatory. The spectrograph was designed to take advantage of the imaging and pointing capabilities of the telescope to obtain ultraviolet spectra with spectral resolution comparable to large, ground-based coudé instruments. Some of the results of the ground-based testing program are described, along with applications of these properties to future science programs.

Hinkle, K. H.

doi: 10.1086/131206pmid: N/A

Recent results from high-resolution, high signal-to-noise ratio spectroscopy at a variety of wavelengths are reviewed. Three topics are discussed in detail: obscured carbon stars, M supergiants, and Miras. The impact of high resolution on circumstellar chemistry and kinematics is emphasized.

Geballe, T. R.

doi: 10.1086/131207pmid: N/A

A brief summary of the major events in star formation is given. Three infrared spectroscopic phenomena currently being studied in star-forming regions are discussed: atomic hydrogen recombination lines in protostars, molecular hydrogen emission lines in shocked clouds, and solid-state absorption features due to molecules on grain mantles.

Vogt, S. S.; Penrod, G. D.

doi: 10.1086/131208pmid: N/A

A technique for imaging the surfaces of certain rapidly rotating spotted stars is discussed. The method exploits the correspondence between wavelength position across a rotationally broadened spectral line and spatial position across the stellar disk. Preliminary Doppler Images of the RS CVn star HR 1099 show spots which exhibit a striking similarity in shape and location to X ray images of solar coronal holes. It is suggested that the large star spots on RS CVn's and other active late-type stars emerge at low latitude as scaled-up analogs of solar complexes, but as they migrate poleward, they more closely resemble photospheric analogs of solar coronal holes. The evolution of starspots appears remarkably similar to that of large-scale magnetic fields of the sun.

Campbell, B.

doi: 10.1086/131209pmid: N/A

A number of techniques for determining stellar radial velocities with a precision better than 100 m s-1 are now becoming available. Three types of precision velocity techniques have been proposed, using for wavelength reference either telluric lines, Fabry-Perot fringes, or lines generated in an absorption cell. The author has used the latter technique, with a hydrogen fluoride cell, to obtain time series observations of Procyon on three nights. The internal error in these velocities is 10 m s-1, and the mean night-to-night difference is about 6 m s-1. These results suggest that the HF technique has good long-term stability, and therefore can be applied to the search for sub-stellar mass companions to solar-type stars.

Foltz, C. B.; Wilkes, B. J.; Weymann, R. J.; Turnshek, D. A.

doi: 10.1086/131224pmid: N/A

Spectroscopic observations of the broad-absorption-line QSO (BAL QSO) H1011+091, an object with a rich and complex emission/absorption-line spectrum are presented. Consideration is given the recent suggestions that this object possesses two sets of emission lines and an attempt is made to show that an alternative interpretation is more consistent with the data. Specifically, the apparent doubling of the lines may be due to a combination of low-velocity broad-absorption-line material and unusually strong Al III lambda 1858 emission.

Harris, G. L. H.; Hesser, J. E.; Massey, P.; Peterson, C. J.; Yamanaka, J. M.

doi: 10.1086/131225pmid: N/A

Photographic, spectroscopic, and photometric data obtained during 13 days of observation in April 1983 of the bright 1983 supernova in NGC 4753 are presented and discussed. The general appearance of the spectra is that of a typical type I event, including prominent features at wavelengths of about 3970 and 4600. The UBV photometry results are also typical of this class of supernovae. The light curve results suggest that the 1983 event may be one of Barbon's 'fast class' of supernovae.

Webster, B. L.

doi: 10.1086/131226pmid: N/A

A satisfactory southern standard system for photometry of the nebular emission lines forbidden O III lambda 5007, H-beta, and H-gamma has been set up. Observations of 72 planetary nebulae and related objects are presented.