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Full-Text Articles in Instrumentation
Extended Variability Of The Symbiotic Star Ag Draconis, Menas Kafatos, S. R. Meier
Extended Variability Of The Symbiotic Star Ag Draconis, Menas Kafatos, S. R. Meier
Mathematics, Physics, and Computer Science Faculty Articles and Research
We have analyzed the complete set of available IUE (International Ultraviolet Explorer) spectra for the symbiotic star AG Draconis covering the period from 1979 to 1989. All absolute line fluxes and wavelengths have been obtained for the prominent emission lines in the λλ1200-3200 wavelength range. These spectra contain observations which were taken before, during and after the two extended outbursts which occurred on 1980 November to 1981 November and 1985 February to 1986 January. These two outburst events have two maxima that are separated by ~1600 days, a time scale not known to be associated with the star, but which …
Rx Puppis: Detection Of Asymmetrical Radio Structure, J. M. Hollis, F. Yusef-Zadeh, T. J. Cornwell, R. J. Oliverson, A. G. Michalitsianos, Menas Kafatos
Rx Puppis: Detection Of Asymmetrical Radio Structure, J. M. Hollis, F. Yusef-Zadeh, T. J. Cornwell, R. J. Oliverson, A. G. Michalitsianos, Menas Kafatos
Mathematics, Physics, and Computer Science Faculty Articles and Research
Subarcsecond ( ~0':3 x ~0':1) observations of the RX Puppis symbiotic system with the Very Large Array (VLA) have resolved 2 cm continuum emission which deviates from a previously reported circularly symmetric radio distribution. The radio structure is comprised of at least three nearly colinear components. Under the assumption that the strongest feature is coincident with the hot star, the other two features lie 230 and 590 AU distant. These radio features are reminiscent of small-scale radio structure detected toward R Aquarii, another symbiotic star system, and probably represents material ejected from the RX Puppis system at an earlier epoch.
The C Iv Doublet Ratio Intensity Effect In Symbiotic Stars, A. G. Michalitsianos, Menas Kafatos, R. P. Fahey, R. Viotti, A. Cassatella, A. Altamore
The C Iv Doublet Ratio Intensity Effect In Symbiotic Stars, A. G. Michalitsianos, Menas Kafatos, R. P. Fahey, R. Viotti, A. Cassatella, A. Altamore
Mathematics, Physics, and Computer Science Faculty Articles and Research
The first successful high-resolution ultraviolet spectra in the λλ 1200-2000 wavelength range of the symbiotic variable R Aquarii and its nebular Jet were obtained in 1987 July with the International Ultraviolet Explorer (IUE). The line profile structure of the C IV λλ1548, 1550 doublet in the jet indicates multicomponent velocity structure from an optically thin emitting gas. The C IV doublet profiles in the compact H II region engulfing the Mira and hot companion binary also suggest multicomponent structure, in which the radial velocities range up to ~ -100 km s^- 1. The value of the doublet intensity ratio in …
Sub-Arc Second 2 Centimeter Continuum And Sio Spectral Line Observations Of R Aquarii, J. M. Hollis, A. G. Michalitsianos, Menas Kafatos, M. C. H. Wright, W. J. Welch
Sub-Arc Second 2 Centimeter Continuum And Sio Spectral Line Observations Of R Aquarii, J. M. Hollis, A. G. Michalitsianos, Menas Kafatos, M. C. H. Wright, W. J. Welch
Mathematics, Physics, and Computer Science Faculty Articles and Research
ub-arc second (- 0'.'15) VLA observations at 2 em have resolved the previously reported 6 em H II region, which engulfs the R Aquarii binary system, into two components. The stronger 2 em component is itself partially resolved (distorted in shape), which may be a consequence of the long-period variable (LPV) wind being subjected to the intense ionizing radiation field of the hot companion's accretion disk, which we suspect is precessing. The distorted radio contours of the central H II region may also suggest that one hemisphere of the extended LPV envelope is directly illuminated by the intense radiation field …
High Dispersion Untraviolet Spectra Of The Peculiar Star Rx Puppis, Menas Kafatos, A. G. Michalitsianos, R. P. Fahey
High Dispersion Untraviolet Spectra Of The Peculiar Star Rx Puppis, Menas Kafatos, A. G. Michalitsianos, R. P. Fahey
Mathematics, Physics, and Computer Science Faculty Articles and Research
High spectral resolution observations of the peculiar star RX Puppis obtained with the International Ultraviolet Explorer suggest the presence of a complex gaseous ring system which surrounds an accreting hot secondary. The anomalous line intensity ratio of the C IV A.A-1548, 1550 doublet during the observations exceeded the optically thick limit, implying the presence of a high-velocity wind. Additionally, the C IV doublet exhibits about four or five narrow emission components, which are redshifted up to velocities of at least - + 300 km s -I (with respect to the rest wavelength).
A Brightening Of The Symbiotic Variable Sy Muscae, A. G. Michalitsianos, Menas Kafatos, W. A. Feibelman, G. Wallerstein
A Brightening Of The Symbiotic Variable Sy Muscae, A. G. Michalitsianos, Menas Kafatos, W. A. Feibelman, G. Wallerstein
Mathematics, Physics, and Computer Science Faculty Articles and Research
The symbiotic variable SY Muscae has been observed with IUE in September 1980 and June 1981 and in the photographic region in May 1981. The entire ultraviolet spectrum brightened between September and June by about a factor of 5. The spectrum shows high excitation including emission from N v and high electron density, about 10^10 cm^-3 as determined from various line ratios in the ultraviolet. The optical spectrum is dominated by permitted lines; even [0 m] is very weak again indicating high density in the ionized region. The increase in ultraviolet continuum and line emission may be due to enhanced …
Ultraviolet Observations Of Four Symbiotic Stars, A. G. Michalitsianos, Menas Kafatos, W. A. Feibelman, R. W. Hobbs
Ultraviolet Observations Of Four Symbiotic Stars, A. G. Michalitsianos, Menas Kafatos, W. A. Feibelman, R. W. Hobbs
Mathematics, Physics, and Computer Science Faculty Articles and Research
Observations were obtained with the International Ultraviolet Explorer (IUE) of four symbiotic stars. The UV spectra of YY Her, SY Mus, CL Sco, and BX Mon are characterized by varying degrees of thermal excitation. We have analyzed these low resolution spectra in terms of line-blanketed model atmospheres of early A, B, and F type stars in order to identify the nature of the hot companion in these systems. The expected emission from early main sequence stars does not fully explain the observed distribution of UV continuum energy over the entire IUE spectral range (1200-3200 A). More likely the observed continuum …
Iue Observations Of The Peculiar Star Rx Puppis, Menas Kafatos, A. G. Michalitsianos, W. A. Feibelman
Iue Observations Of The Peculiar Star Rx Puppis, Menas Kafatos, A. G. Michalitsianos, W. A. Feibelman
Mathematics, Physics, and Computer Science Faculty Articles and Research
We have obtained the first high-dispersion observations of RX Pup in the wavelength region 1200-2000 A with the International Ultraviolet Explorer. RX Pup has been classified a symbiotic star and has been compared to slow novae as well as to 11 Carinae. The anomalies that we observed in high-excitation lines in RX Pup such as He II, 0 III], C III], C IV, and Si IIIl that show split line profiles, Doppler displaced multiple components, and possible inverse P Cygni profiles inN III] and N IV J suggest dynamic activity in circumstellar material that probably has the form of rings …
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, …