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IUE observations of mass ejection by the close binary system AO Cas.
Kondo, Y.; McCluskey, G. E.
It is noted that 11 high-resolution spectra in the far-ultraviolet and two high-resolution spectra in the mid-ultraviolet were obtained. A high-velocity stellar wind exists as indicated by narrow shortward-displaced absorption features superposed on the P Cygni lines of N V, Si IV, and C IV. Absorption lines caused by N IV and C III are present an…
HR 4511 : a probable cepheid with a supergiant-like hot companion.
Parsons, S. B.
IUE observations have shown HR 4511 to have an early B-type companion with a strong stellar wind. Fitting the energy distribution of the system from far-UV to middle-IR yields a difference of about 3.2 mag at the V passband. Since HR 4511 is in the small cluster Stock 14 and has M(V) = -7.8, M(V) for the secondary is about -4.6, which is only slig…
IUE observations of eight OB stars in NGC 2244 : ultraviolet continuaand extinction.
Massa, D.; Conti, P. S.
Low-resolution IUE ultraviolet continuum observations of O and B stars in the young open cluster NGC 2244 are presented. When only relative energy distributions are considered, thereby eliminating any dependence on reddening corrections or absolute energy calibrations, it is found that the ultraviolet energy distributions of the O stars have signi…
The far-ultraviolet energy distribution of two globular cluster blue horizontal-branch stars in M 13.
de Boer, K. S.; Code, A. D.
The far-UV energy distribution of two blue horizontal-branch (BHB) stars detected in the nucleus of M13 is presented. Their continua can be characterized by a model atmosphere of an effective temperature of 15,000 to 20,000 K and log g = 4.5, and it follows that V is in the range 15.9-16.7 for these stars. Comparison with integrated photometry by …
UV observation of the nucleus of NGC 3077.
Galletta, G.; Benacchio, L.
Spectroscopic observations in the range 1200-2000 A of the Ir II galaxy NGC 3077 made with the IUE telescope using the large aperture (10 arcsec x 20 arcsec) slit in low-dispersion mode are presented. The observations show the presence of a hot stellar component (20,000-23,000 K) spatially distributed in an asymmetric way. Analysis of the slit pos…
Far-ultraviolet energy distributions of the metal-poor A stars HD 109995 and HD 161817.
Boehm-Vitense, E.
Low-resolution IUE spectra at wavelengths between 1300 and 3400 A of the metal-poor stars HD 109995 (A1p) and HD 161817 (A4p) have been compared with model-atmosphere energy distributions computed by Kurucz (1979). Good overall agreement is found. Effective temperatures, metal abundances, and angular diameters could be determined. Assuming an abso…
The spectra of two new intermediate helium stars.
Drilling, J. S.
The stars designated as LSS 2394 and LS II + 36 deg 37 in the Case-Hamburg Luminous Stars surveys are found to be intermediate helium stars. The environment and spectrum of LSS 2394 (CPD -62 2124) appear to be quite similar to those of Sigma Ori E in a number of respects, including close proximity to two other OB stars, membership in a rich O asso…
IUE high-dispersion spectrum of R Aqr.
Johnson, H. M.
Emission-line spectra of several ions were observed in R Aqr in the wavelength range 1900-3000 A. C II diagnostics gives an electron density of about 400,000/cu cm and an electron temperature of about 10,000 K. The Mg II doublet profiles are grossly asymmetric, of a P Cygni type with terminal ejection velocity of at least 200 km/s. This is like Mg…
Hybrid atmospheres and winds in supergiants stars.
Raymond, J. C.; Dupree, A. K.; Hartmann, L.
Ultraviolet spectra showing evidence for hybrid chromospheres and winds are found in the supergiant Alpha Aqr (G2 Ib) and Beta Aqr (G0 Ib). Characteristics of both solar-type transition regions and the cool chromospheric regions typical of later supergiants such as Lambda Vel (K5 Ib) are present. This suggests a gradual transition between activity…
Outer atmospheres of cool stars. V. IUE observations of Capella: the rotation-activity connection.
Linsky, J. L.; Ayres, T. R.
UV spectra of Capella (G6 III + F9 III) obtained with the IUE are analyzed. High-resolution emission-line profiles taken near the elongation at phase 78 days suggest that virtually all of the emission in transition-region lines and most of the emission in chromospheric lines comes from the late-F secondary of the system. It is suggested that the o…