Search Publications
Optical photometry and UV spectroscopy of the flare star GL 735 (=V1285 Aql).
Doyle, J. G.; Butler, C. J.; Byrne, P. B. +1 more
The authors present optical photometry of flares and possible spot variations on the star Gl 735. Consideration of the energetics of the optical flares suggests that the star may be underactive when compared to other flare stars of the same spectral type. This conclusion is not supported however by an estimate of the radiative loss rate from the l…
A study of the Herbig Ae-type stars UX Ori and CD -44°3318 based on IUE spectra, and on visual and infrared photometry.
Djie, H. R. E. Tjin A.; Remijn, L.; Thé, P. S.
Far ultraviolet spectra of the two Herbig Ae stars UX Ori and CD -44°3318 are used to derive spectral types A2 III for UX Ori, and A0 - 1 III for CD -44°3318. The spectral energy distributions are in agreement with that of a Kurucz model with Teff = 9500K and log g = 4.0. In the near infrared both stars have a large excess of radiation,…
The nature of radio-quiet QSO's VLA observations of 0026+129, 0205+024 and 1351+640.
Sitko, M. L.; Rudnick, L.; Stein, W. A.
VLA maps of 'radio-quiet' QSOs are reported. Extended emission is found on linear scales of about 10 kpc, larger than that observed in Seyfert galaxies, but smaller than most radio-loud objects. The spectral properties of some radio-quiet objects are also very similar to those of radio-quiet Seyfert galaxies such as NGC 4151; some radio-quiet QSOs…
An analysis of V861 SCO - II. The stellar wind.
Howarth, I. D.
V861 Sco (= HD 152667) is a close binary with an early-type primary at one time suspected of having a compact (black hole) companion. It is now known that the system comprises a lobe-filling B0Ia star with a B2V secondary. It is pointed out that mass loss from the primary via its stellar wind is of considerable interest, since few close binaries h…
Ultraviolet spectroscopy of the planetary nebula in the Fornax galaxy.
Gull, T. R.; Stecher, T. P.; Maran, S. P. +2 more
The planetary nebula in the Fornax dwarf spheroidal galaxy is carbon rich, according to calculations based on measurements of the 1909 A emission line doublet of semiforbidden C III obtained with the International Ultraviolet Explorer. The ratio N(C)/N(O) is approximately equal to 3.7, comparable to the largest reliably determined carbon/oxygen ra…
Abrupt changes in the C IV resonance lines of theta CR B.
Stalio, R.; Doazan, V.; Thomas, R. N. +2 more
It is noted that the Theta CrB far-UV spectrum changes from conspicuous presence, to complete disappearance, to reappearance at a higher velocity than the previous one, have occurred with a phase lag of about 3 years after the disappearance of a weak shell phase of short duration which was observed in the visible in 1979. This sequence is interpre…
The absorption near 1400 A in the spectra of additional DA white dwarfs.
Wegner, G.
Ultraviolet spectroscopic observations of five white dwarfs having published spectral types of DA made with the International Ultraviolet Explorer (IUE) satellite are reported. The three coolest objects: GD279 (0148 + 46), W485A (1327 - 08), and G231 - 40 (2117 + 53) have easily detected absorptions near lambda 1400. Of the two remaining stars, PG…
IUE observations of weak G-band stars.
Sneden, C.; Parthasarathy, M.; Bohm-Vitense, E.
High- and low-resolution ultraviolet spectra of several weak G-band giants have been obtained with the IUE satellite, to derive Be abundances and to search for degenerate companions. The abundances of Be in these stars are about log epsilon (Be) approximately -0.5. These values are in good agreement with the Be abundances of Hyades giants, and are…
On interstellar absorption toward Cepheus OB2.
Hobbs, L. M.
A weak interstellar absorption line which can be identified as the forbidden line of Fe X 6375 A is observed in the spectrum of the A2 Ia star Nu Cep, which is a member of the Cepheus OB2 association. The equivalent width, width, and radial velocity of the line differ indistinguishably from those of similar absorption previously detected uniquely …
Ultraviolet spectroscopy of hot young stars with infrared excesses : NGC 2264 - W 46, W 90 and W 100.
Sitko, M. L.; Simon, T.; Meade, M. R.
New ultraviolet data are combined with optical data to investigate the wavelength-dependent extinction of the stars W46, W90, and W100 in the young galactic cluster NGC 2264. The observations of W90 confirm the existence of anomalous (circumstellar) dust extinction with a ratio of total to selective extinction, R greater than 7. This extinction is…