THE RENAISSANCE OF HIGH-RESOLUTION SPECTROSCOPY - NEW TECHNIQUES, NEW FRONTIERSWolff, S. C.
doi: 10.1086/131203pmid: N/A
Instrumentation newly available for spectroscopy in the UV, IR, and optical regions of he spectrum has greatly broadened the range of problems that can be addressed through measurements made at high spectral resolution. In this issue and the next, the Publications of the Astronomical Society of the Pacific presents review papers that summarize some of the relevant developments in astronomical detector systems and describe recent work on a range of topics from the study of planetary atmospheres to the analysis of quasar absorption-line spectra.
PROGRESS IN STELLAR CHROMOSPHERES OBSERVED WITH THE INTERNATIONAL ULTRAVIOLET EXPLORER SATELLITE.Baliunas, S. L.
doi: 10.1086/131204pmid: N/A
The historical knowledge gathered over the past two decades of visible spectrum studies, predominantly at Ca II H and K, combined with detailed theoretical models and high spectrum-and spatial-resolution work on the solar atmosphere from space provide the framework for ultraviolet measurements from IUE for furthering our understanding of the solar-and-stellar activity connection. Quantitative measurements of the behavior of stellar chromospheric and coronal emission can be investigated as a function of stellar parameters such as age, rotation rate, and mass. Together the visible and ultraviolet spectra probe the stellar atmospheres as a function of height and reveal the energy budget in a variety of late-type stars. Atmospheric inhomogeneities such as stellar active areas, spots, and flares can be profitably studied in the ultraviolet and visible. At high spectrum resolutions with IUE, the dynamics of the outer atmospheres, including stellar winds and mass outflows, yield constraints on global models for mass loss in late-type stars.
ULTRAVIOLET HIGH-RESOLUTION SPECTROSCOPY FROM THE SPACE TELESCOPEEbbets, 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.
DOPPLER IMAGING OF SPOTTED STARS : APPLICATION TO THE RS CANUM VENATICORUM STAR HR 1099.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.
PRECISION RADIAL VELOCITIESCampbell, 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.
OBSERVATIONS OF THE BROAD-ABSORPTION-LINE QSO H 1011+091.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.
THE 1983 SUPERNOVA IN NGC 4753.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.