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Full-Text Articles in Instrumentation
Ci Cygni Since The 1980 Eclipse, R. E. Stencel, Andrew G. Michalitsianos, Menas Kafatos
Ci Cygni Since The 1980 Eclipse, R. E. Stencel, Andrew G. Michalitsianos, Menas Kafatos
Mathematics, Physics, and Computer Science Faculty Books and Book Chapters
Following the 1980 eclipse of the 855 day period symbiotic binary CI Cyg, we were confronted with a data set showing high excitation resonance lines which were largely uneclipsed but brightening on an orbital timescale, and intercombination lines exhibiting pronounced but nontotal eclipses and which were fading on an orbital timescale. Our model invoked a low density dissipating nebula surrounding the hot companion to explain the intercombination lines, and a shock between stellar winds to interpret the resonance lines. Subsequent synoptic observations have revealed continuing changes in the W emission line fluxes, consistent with those described above, except for the …
Observations And Analysis Of The Aquarii Jet, Menas Kafatos, Andrew G. Michalitsianos
Observations And Analysis Of The Aquarii Jet, Menas Kafatos, Andrew G. Michalitsianos
Mathematics, Physics, and Computer Science Faculty Books and Book Chapters
Ultraviolet, optical and radio observations of the symbiotic star R Aquarii are discussed in the light of the discovery of a bright radio and optical jet from this star. The star is probably a binary with a period of 44 years. The VLA maps of the jet reveal a protruding structure extending-10 arc sec from the central radio source with a position angle virtually identical to that of the optical jet observed at Lick. We interpret the observations of R Aqr as indicating the existence of an accretion disk around an unseen companion. The hot subdwarf has effective temperature ,(65,000 …
Uv Emission From The M1 Supergiant Tv Gem, Andrew G. Michalitsianos, Menas Kafatos
Uv Emission From The M1 Supergiant Tv Gem, Andrew G. Michalitsianos, Menas Kafatos
Mathematics, Physics, and Computer Science Faculty Books and Book Chapters
Low and high dispersion ultraviolet spectra were obtained of the Ml supergiant TV Gem with IUE. Previous IUE observations of this late type supergiant revealed unexpected W continuum emission, perhaps arising from an early B companion. Low resolution spectra obtained approximately one year apart suggest that the strong Si I11 in-combination perhaps with 0 I at wavelengths % A1300 A varies considerably with time. Large variation the column density is required to explain these changes. Sporadic mass expulsion with mass loss rates dM/dt * 10-5 S y r - l from the M supergiant could lead to a dense circumstellar …
Preliminary Report On Iue Spectra Of Crab Nebula, K. Davidson, T. R. Gull, S. P. Maran, T. P. Stecher, Menas Kafatos, V. L. Trimble
Preliminary Report On Iue Spectra Of Crab Nebula, K. Davidson, T. R. Gull, S. P. Maran, T. P. Stecher, Menas Kafatos, V. L. Trimble
Mathematics, Physics, and Computer Science Faculty Books and Book Chapters
The Crab Nebula is marginally observable with the IUE. Observations of the optically brightest filamentary regions, made with IUE in August 1979, show the C IV x1549, He II x1640, and C III] x1909 emission lines. The intensities of these lines have been compared with visual-wavelength data. It appears that carbon is not overabundant in the Crab; carbon/- oxygen is approximately "normal" oxygen is slightly scarcer than "normal" as a fraction of the total mass.
Iue Observations Of Two Late Type Stars Bx Mon (M4 + Pec) And Tv Gem (M1 Iab), Andrew G. Michalitsianos, R. W. Hobbs, Menas Kafatos
Iue Observations Of Two Late Type Stars Bx Mon (M4 + Pec) And Tv Gem (M1 Iab), Andrew G. Michalitsianos, R. W. Hobbs, Menas Kafatos
Mathematics, Physics, and Computer Science Faculty Books and Book Chapters
IUE observations of two late type stars BX Mon and TV Gem have been obtained that reveal the emission properties in the ultraviolet of subluminous companions. Analysis of the continuum emission observed from BX Mon suggests the companion is a middle A III star. High excitation emission lines observed between 1200 A and 2000 A (C IV, Si Ill], C III ) that generally do not typify emission observed in either late M type variables or A type stars are also detected. It is suggested that these strong high-excitation lines arise in a large volume of gas heated by non-radiation …
Ingress Observations Of The 1980 Eclipse Of The Symbiotic Star Ci Cygni, R. E. Stencel, Andrew G. Michalitsianos, Menas Kafatos, Alexander A. Boyarchuk
Ingress Observations Of The 1980 Eclipse Of The Symbiotic Star Ci Cygni, R. E. Stencel, Andrew G. Michalitsianos, Menas Kafatos, Alexander A. Boyarchuk
Mathematics, Physics, and Computer Science Faculty Books and Book Chapters
One of the major results from the IUE may prove to be the new knowledge gained by studies of the ultraviolet spectra of symbiotic stars. Symbiotics combine spectral features of a cool M giant-like photosphere with strong high excitation emission lines of nebular origin, superposed. An excellent pre-UV review has been given by Swings (i). The UV spectra are dominated by intense permitted and semi-forbidden emission lines and weak continua indicative of hot compact objects and accretion disks. Two symbiotics, AR Pay and CI Cyg are thought to be eclipsing binaries, and we have begun IUE observations during the predicted …
Iue Observations And Interpretation Of The Symbiotic Star Rw Hya, Menas Kafatos, Andrew G. Michalitsianos
Iue Observations And Interpretation Of The Symbiotic Star Rw Hya, Menas Kafatos, Andrew G. Michalitsianos
Mathematics, Physics, and Computer Science Faculty Books and Book Chapters
IUE observations of the high excitation symbiotic star RW Hya (gM2 + pec) have been obtained. Analysis of the intense UV continuum observed between II00 A to 2000 A suggests this star is a binary system in which the secondary is identified as a hot subdwarf with T _. _I0 D K. We deduce a distance to the system of ~1000 pc. The UV spectrum consists of mainly semi-forbidden and allowed transition lines of which the ClV (1548 A, 1550 A) emission lines are particularly strong, and UV continuum at both shorter and longer wavelengths. Strong forbidden lines seem to …
Iue Observations Of Circumstellar Emission From The Late Type Variable R Aqr (M7 + Pec), R. W. Hobbs, Andrew G. Michalitsianos, Menas Kafatos
Iue Observations Of Circumstellar Emission From The Late Type Variable R Aqr (M7 + Pec), R. W. Hobbs, Andrew G. Michalitsianos, Menas Kafatos
Mathematics, Physics, and Computer Science Faculty Books and Book Chapters
As part of a program to observe circumstellar emission from late type stars, IUE observations of R Aqr (M7 + pec) have been obtained in low dispersion. Strong permitted, semi-forbidden and forbidden emission lines are seen, superimposed on a bright ultraviolet continuum. We deduce that the strong emission line spectrum that involves C III], C IV, Si III], [0 II] and [0 lll] probably arises from a dense compact nebula the size of which is comparable to the orbital radius of the binary system of which R Aqr is the primary star. The low excitation emission lines of Fe II, …