Search Publications
Determinations of the interstellar reddening toward Wolf-Rayet stars of the nitrogen sequence from observed UBV color indices.
Schmutz, W.; Vacca, W. D.
We demonstrate that continuum discontinuities, or "jumps", are present in the spectra of some Wolf-Rayet stars and that current models of Wolf-Rayet stars predict such jumps and provide good fits to the observed continua. Using a relation between the size of the He II (n = 4) jump at 3645 A and the intrinsic (b - v)_0_ color found from the model a…
High resolution observations of chromospheric lines in late-type dwarfs.
Houdebine, E. R.; Byrne, P. B.; Panagi, P. M.
High resolution H-alpha absorption- and emission-line profiles are reported for 11 stars of spectral types ranging from K5V to M3V, and the profiles of NaI(D), HeI(5876A), and CaII(IR) are given for portions of the sample. The observations were taken with the Qubes spectrograph, and the data are reduced by comparing the spectral data with observat…
The UV properties of normal galaxies. I. The IUE data.
Longo, G.; Capaccioli, M.; Ceriello, A.
As a first step toward a better understanding of the energy distribution of normal galaxies at wavelengths shorter than 3300 A, all IUE low resolution spectra of normal galaxies have been reduced to a photometric system consisting of seven intermediate-widths bands, five of which matching the ANS photometric system. Dereddened ultraviolet magnitud…
Short term H-alpha variations in two Herbig PMS stars : HR 5999 and HD 52721.
Catala, C.; The, P. S.; Tjin A Djie, H. R. E. +2 more
We present high spectral resolution observations of Hα as well as V photometry and IUE observations for two Herbig pre-main sequence stars, HR 5999 and HD 52721. These observations, performed in 1985, were aimed at studying short-term variations of the Hα line, within one night and from night to night. Hα spectra of comparison stars are also displ…
Photometric and spectroscopic studies of cool stars discovered in EXOSAT X-ray images. I. Time variability and spectral classification of eight southern stars.
Tagliaferri, G.; Pasquini, L.; Pallavicini, R. +4 more
As part of a larger program to study the optical properties of serendipitous Exosat sources, optical photometry and low-resolution spectroscopy are presented for eight southern stars which have been identified as optical counterparts of Exosat sources. X-ray flux variability has been detected for three of them. In all three cases the optical count…
Twelve years of IUE spectra of the interacting binary VV Cephei.
Stencel, R. E.; Neff, D. H.; Bauer, W. H.
All well-exposed high-resolution IUE spectra obtained of the eclipsing binary system VV Cephei (M2Iabep + B) are examined. High-temperature absorption features attributable to the hot companion were detected, indicating that the companion (or the inner regions of its accretion disk) are not as hot as a B1-B2 star. Doubling of Fe II (UV 1) lines, w…
Location and thickness of the nearest neutral gas cloud in the direction of Auriga-Perseus.
de Boer, K. S.; Lilienthal, D.
High dispersion IUE spectra of stars in the general direction of Auriga-Perseus show clear interstellar absorption lines whose strengths are used to derive information about the spatial distribution of the gas on the lines of sight. The distance to the nearest neutral cloud in this direction is about 50 pc; it has a depth of approximately 15 pc an…
UBVRI photometry of G, K, M HIPPARCOS stars. II.
Jordi, C.; Figueras, F.; Torra, J. +2 more
As indicated by Grenon (1989), the data of the present series of reports on the UBVRI photometry of late-type stars in the Hipparcos Input Catalog are to be employed in computations of Hipparcos observing time, as well as in evaluating the observability of faint stars by the satellite. Attention is here given to late type stars in the V = 8-12 ran…
A line identification study of the IUE SWP high dispersion spectrum of the UV-bright star Barnard 29 of Messier 13.
Leckrone, D. S.; Cacciari, C.; Adelman, S. J.
A line identification study was performed of the coaddition of three SWP high dispersion IUE exposures of the UV-bright star Barnard 29 of Messier 13. One of these images took two IUE shifts. The previous study by de Boer and Savage (1983) was extended and stellar lines of C I, C II, C III, C IV, N I, N III, O I, O III, O IV,Al III, Si II, Si III,…
Optical positions of radiostars. III.
Costa, E.; Loyola, P.
Precise optical positions, relative to either the Perth 70 or the AGK3R catalog have been obtained for 44 radiostars proposed to the Hipparcos observing list. Precision levels between 0.17 and 0.28 arcsec were obtained.