scholarly journals The Symbiotic Binary System AG Pegasi

1980 ◽  
Vol 88 ◽  
pp. 535-542 ◽  
Author(s):  
Charles D. Keyes ◽  
Mirek J. Plavec
Keyword(s):  
Binary System ◽  
Emission Lines ◽  
Complete Coverage ◽  
Cool Component ◽  
Relative Contribution ◽  
Photometric Observations

A complete coverage of the spectrum of AG Peg has been obtained between wavelengths 1200 − 7000 A by us, and can be supplemented by IR photometric observations by others. Our IUE observations yield a lower value of E(B-V), about 0.12. The two stellar components are easily recognized, but their characteristics are still rather uncertain.The cool component may be a normal M1.7 III giant, but the temperature and luminosity of the hot star remain largely indeterminate. Firstly, there are no good models for a hot subdwarf, and secondly, it is difficult to determine the relative contribution of the star itself and the surrounding hydrogen cloud.The emission lines observed in the UV have double or triple structure, indicating two or three distinct emitting regions.

scholarly journals Variability of NGC 3783: First Results from an Intensive Ground-Based Monitoring Campaign

1994 ◽  
Vol 159 ◽  
pp. 407-407
Author(s):  
Giovanna M. Stirpe
Keyword(s):  
Emission Lines ◽  
Intensive Monitoring ◽  
Monitoring Campaign ◽  
Broad Emission ◽  
Photometric Observations ◽  
First Results ◽  
The Continuum

The International AGN Watch collaboration undertook an intensive monitoring campaign of the bright Seyfert 1 galaxy NGC 3783 between December 1991 and August 1992, in order to study the variations of the continuum and broad emission lines. Spectroscopic and photometric observations took place at several ground-based observatories and formed the optical/IR counterpart to the UV observations conducted with the IUE (Reichert et al. 1993).

scholarly journals Onthe changes in the physical properties of the ionized region around the Weigelt structures in η Carinae over the 5.54-yr spectroscopic cycle

2020 ◽  
Vol 495 (3) ◽  
pp. 2754-2770 ◽  
Author(s):  
M Teodoro ◽  
T R Gull ◽  
M A Bautista ◽  
D J Hillier ◽  
G Weigelt ◽  
...  
Keyword(s):  
Binary System ◽  
Electron Temperature ◽  
Ionization Potential ◽  
Orbital Period ◽  
Equatorial Plane ◽  
Proper Motion ◽  
Emission Lines ◽  
Central Source ◽  
High Ionization ◽  
Orbital Cycle

ABSTRACT We present HST/STIS observations and analysis of two prominent nebular structures around the central source of η Carinae, the knots C and D. The former is brighter than the latter for emission lines from intermediate- or high-ionization potential ions. The brightness of lines from intermediate- and high-ionization potential ions significantly decreases at phases around periastron. We do not see conspicuous changes in the brightness of lines from low-ionization potential (<13.6 eV) ions over the orbital period. Line ratios suggest that the total extinction towards the Weigelt structures is AV = 2.0. Weigelt C and D are characterized by an electron density of 106.9 cm−3 that does not significantly change throughout the orbital cycle. The electron temperature varies from 5500 (around periastron) to 7200 K (around apastron). The relative changes in the brightness of the He i lines are well reproduced by the variations in the electron temperature alone. We found that, at phases around periastron, the electron temperature seems to be higher for Weigelt C than that of D. The Weigelt structures are located close to the Homunculus equatorial plane, at a distance of about 1240 au from the central source. From the analysis of proper motion and age, the Weigelt complex can be associated with the equatorial structure called ‘Butterfly Nebula’ surrounding the central binary system.

On the Optical Spectrum of 89 Her

2011 ◽  
Vol 20 (1) ◽  
Author(s):  
Tõnu Kipper
Keyword(s):  
Chemical Composition ◽  
High Resolution ◽  
Binary System ◽  
Optical Spectrum ◽  
Emission Lines ◽  
Refractory Elements ◽  
Systemic Velocity ◽  
Metal Deficiency ◽  
Low Levels ◽  
Process Elements

AbstractThe high resolution spectra of a post-AGB candidate, binary system 89 Her, were analysed for the chemical composition. The star was found to be metal deficient with [Fe/H] = -0.50±0.20. No enhancement of s-process elements was found. The refractory elements are depleted but this is not the reason of metal deficiency. More than 320 narrow and weak emission lines from low levels of neutral metals were identified. Radial velocities of these lines coincide with the systemic velocity. We propose that the circum-binary dusty disk is observed face-on.

Photometric observations of the binary system V350 Lacertae

1992 ◽  
Vol 188 (1) ◽  
pp. 151-158
Author(s):  
O. Demircan ◽  
E. Derman ◽  
G. Kahraman
Keyword(s):  
Binary System ◽  
Photometric Observations

scholarly journals PHOTOMETRIC OBSERVATIONS OF THE CONTACT BINARY SYSTEM V523 CASSIOPEIAE

2006 ◽  
Vol 23 (3) ◽  
pp. 177-188 ◽  
Author(s):  
Jang-Hae Jeong ◽  
Chun-Hwey Kim ◽  
Yong-Sam Lee
Keyword(s):  
Binary System ◽  
Photometric Observations ◽  
Contact Binary

scholarly journals Details of the Classification of Symbiotic Stars: The Case of the Symbiotic Nova AG Peg

2016 ◽  
Vol 25 (3) ◽  
Author(s):  
A. A. Tatarnikova ◽  
M. A. Burlak ◽  
D. V. Popolitova ◽  
T. N. Tarasova ◽  
A. M. Tatarnikov
Keyword(s):  
Component Model ◽  
Symbiotic Stars ◽  
Cool Component ◽  
Photometric Observations

AbstractWe analyze archival and modern spectroscopic and photometric observations of the oldest known symbiotic nova AG Peg. Its new outburst (which began in 2015 June) differs greatly from the first one (which occurred in the mid-1850s). Fast photometric evolution of the new outburst is similar to that of Z And-type outbursts. However, the SED of AG Peg during the 2015 outburst, as well as during the quiescence, can be fitted by a standard three-component model (cool component + hot component + nebula), which is not common for an Z And-type outburst.

scholarly journals Subfuors in Orion association

1990 ◽  
Vol 137 ◽  
pp. 253-256
Author(s):  
L.G. Gasparian ◽  
A.S. Melkonian ◽  
G.B. Ohanian ◽  
E.S. Parsamian
Keyword(s):  
Emission Lines ◽  
Absorption Bands ◽  
Photometric Observations ◽  
Orion Association ◽  
T Tau Type Stars ◽  
T Tau

Results of spectral and photometric observations of Sugano star = V1143 Ori in brightness minimum and near it are given. Emission lines of HI, CaII, FeI, TiI, TiII and TiO absorption bands are detected. The appearing envelope is observed also in minimum. A brightness increase of Shanalstar V1118 Ori is observed. In its spectrum lines of HI, CaII, FeI, FeII are found, testifying to formation of an envelope.During the last ten years data on T Tau type stars which have fuor-like outburst-subfuors were obtained. Two such stars were found in Orion association. These are V1118 Ori [1] and V 1143 Ori [2,3]. In recent years, in Byurakan observatory observations of these stars have been made.

scholarly journals Nova V1500 Cyg - Photometry and Period Variations Study

1977 ◽  
Vol 42 ◽  
pp. 194-200
Author(s):  
I. Semeniuk ◽  
A. Kruszewski ◽  
A. Schwarzenberg-Czerny ◽  
T. Chlebowski
Keyword(s):  
Single Channel ◽  
Brightness Variation ◽  
Emission Lines ◽  
V Band ◽  
Photometric Observations ◽  
Period Variations ◽  
Comparison Stars

This study aims to present our photometric observations of Nova Cygni V1500 1975, and to discuss the period changes of brightness variation on the basis of all available data.The Nova was observed from 2 September 1975 to 26 October 1976 using the single channel UBV photometer attached to the 60-cm reflector of the Ostrowik station of Warsaw University Observatory. The brightness of the Nova decreased considerably during that time and it was necessary to use a sequence of four comparison stars. The variable was usually monitored in the V filter and occasionally measured with B and U filters. The V band is not well suited for observing novae in the nebular stage, since the dominant light contribution comes from O III emission lines.

scholarly journals Photometric and Spectroscopic Variations of the Symbiotic Star EG Andromedae

1988 ◽  
Vol 103 ◽  
pp. 289-290
Author(s):  
A. Skopal ◽  
D. Chochol ◽  
A. Vittone ◽  
A. Mammano
Keyword(s):  
Binary System ◽  
Orbital Period ◽  
Uv Spectroscopy ◽  
Symbiotic Star ◽  
Cool Component

EG And is a symbiotic binary system. The cool component is an M3 III star, the hot one is a subdwarf with temperature 60 250 K and luminosity 1.45 L⊙ (Boyarchuk, 1985). The eclipsing nature of the system suggested from UV spectroscopy by Oliversen et al. (1985) was confirmed photometrically by Chochol et al. (1987). The circular spectroscopic orbit of cool component determined by Oliversen et al. (1985) supposing the orbital period 470 days leads to f(m) = 3.2×10−2 M⊙ and detached configuration.

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