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 A machine learning approach for identification and classification of symbiotic stars using 2MASS and WISE

2018 ◽  
Vol 483 (4) ◽  
pp. 5077-5104 ◽  
Author(s):  
Stavros Akras ◽  
Marcelo L Leal-Ferreira ◽  
Lizette Guzman-Ramirez ◽  
Gerardo Ramos-Larios
Keyword(s):  
Machine Learning ◽  
Learning Approach ◽  
Symbiotic Stars ◽  
Machine Learning Approach

Spectral classification of the cool components of symbiotic stars

1999 ◽  
Vol 23 (2) ◽  
pp. 195-207
Author(s):  
Zhen-xi Zhu ◽  
M. Friedjung ◽  
Chang-chun Huang
Keyword(s):  
Symbiotic Stars ◽  
Spectral Classification

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.

Recent UBVR Photometry of Symbiotic Stars

2003 ◽  
Vol 12 (4) ◽  
Author(s):  
A. Skopal ◽  
M. Vaňko ◽  
T. Pribulla ◽  
D. Chochol
Keyword(s):  
Light Curve ◽  
Active Phase ◽  
Symbiotic Stars ◽  
Short Term ◽  
Quiescent Phase ◽  
Photometric Observations ◽  
Made In

AbstractWe present recent photometric observations of Z And, BF Cyg, and AX Per made in the standard Johnson UBVR system. The main characteristics of their light behavior can be summarized as follows: Z And: our observations cover the recent active phase, from its maximum in 2000 December to the latest measurements (2003 September). BF Cyg: the minimum of the recent wave in the star’s brightness was the deepest ever observed; in 2003 February a short-term flare developed in the light curve. AX Per: from 1995 October the light curve displays signatures of a quiescent phase of the star; in 2003 May a 0.5 mag flare was detected.

scholarly journals The peculiar symbiotic object V1329 Cygni: single-star versus binary models

1982 ◽  
Vol 70 ◽  
pp. 165-168
Author(s):  
Jiri Grygar ◽  
Drahomir Chochol
Keyword(s):  
Emission Line ◽  
Near Infrared ◽  
Emission Lines ◽  
Symbiotic Stars ◽  
Late Type ◽  
Single Star ◽  
Star Versus

The variable emission-line object V1329 Cyg (= HBV 475) was discover red by Kohoutek (1969).Crampton and Grygar (1969) identified more than 100 emission lines in the blue portion of the spectrum, while Andrillat (1969) found evidence for the late-type (M) spectrum in the near infrared. This justified the classification of the object among the symbiotic stars. The classification was subsequently confirmed by all authors who studied the spectroscopic evolution of the object.

scholarly journals Spectral Synthesis of Cool Components of Symbiotic Stars

1992 ◽  
Vol 150 ◽  
pp. 409-410
Author(s):  
Claudio B. Pereira ◽  
Sayd Codina Landaberry
Keyword(s):  
Satisfactory Agreement ◽  
Spectral Synthesis ◽  
Optical Spectra ◽  
Symbiotic Star ◽  
Symbiotic Stars ◽  
Cool Component ◽  
Synthesis Technique ◽  
Solar Abundances

We analyzed the optical spectra of cool component of symbiotic star SY Mus by means of spectral synthesis technique in order to derive the atomic abundances using the Minneart formulae for computing the atmospheric opacities. We obtained a satisfactory agreement between the observed and computed spectra and the resulting abundances were consistent to the solar abundances.

scholarly journals Infrared studies of symbiotic stars

1982 ◽  
Vol 70 ◽  
pp. 27-42 ◽  
Author(s):  
David A. Allen
Keyword(s):  
Spectral Type ◽  
Dust Emission ◽  
Circumstellar Dust ◽  
Symbiotic Stars ◽  
Infrared Photometry ◽  
Late Type ◽  
Cool Component ◽  
Mira Variables ◽  
Infrared Studies

AbstractInfrared photometry and spectroscopy of symbiotic stars is reviewed. It is shown that at wavelengths beyond lym these systems are generally dominated by the cool star’s photosphere and, indeed, are indistinguishable from ordinary late-type giants. About 25% of symbiotic stars exhibit additional emission due to circumstellar dust. Most of the dusty systems probably involve Mira variables, the dust forming in the atmospheres of the Miras. In a few cases the dust is much cooler and the cool component hotter; the dust must then form in distant gas shielded from the hot component, perhaps by an acccretion disk.Spectroscopy at 2μm can be used to spectral type the cool components, even in the presence of some dust emission. Distances may thereby be estimated, though with some uncertainty.Spectroscopy at longer wavelengths reveals information about the dust itself. In most cases this dust appears to include silicate grains, which form in the oxygen-rich envelope of an M star. In the case of HD 330036, however, different emission features are found which suggest a carbon-rich environment.

Relaxation Oscillations in Red-Giant Envelopes and the Symbiotic Stars

1973 ◽  
Vol 2 (4) ◽  
pp. 198-200 ◽  
Author(s):  
P. R. Wood
Keyword(s):  
Absorption Spectrum ◽  
Light Curves ◽  
Emission Lines ◽  
Symbiotic Star ◽  
Symbiotic Stars ◽  
Relaxation Oscillations ◽  
Cool Component ◽  
Cool Star ◽  
Red Giant ◽  
Eruptive Behaviour

The spectrum of a symbiotic star consists of an M-type absorption spectrum, a B-type shell spectrum and nebula emission lines, the relative contributions of these three components varying with time. The light curves of the symbiotic stars vary with a semi-regular period typically 200-800 days while larger eruptions occur on a timescale of ~ 3.5 years. Some suggestions which have been advanced to explain the combination spectrum, variability and eruptive behaviour of the symbiotic stars are: (a)the symbiotic stars are binaries consisting of a hot and cool component.(b)the symbiotic stars consist of a single hot star surrounded by a large optically thick envelope giving the appearance of a hot continuum with the absorption spectrum of a cool star superimposed on it.(c)the symbiotic stars are single stars surrounded by a shock wave heated chromosphere.Although some of the symbiotic stars are undoubtedly binaries (for example, T Coronae Borealis), observatienal evidence suggests that others may be explained by hypothesis (c) above. The calculations described below provide an explanation of the symbiotic stars in conjunction with hypothesis (c).

scholarly journals Properties Of Cool Stellar Components in S-Type Symbiotic Stars

1988 ◽  
Vol 103 ◽  
pp. 37-41
Author(s):  
O.G. Taranova ◽  
B.P. Yudin
Keyword(s):  
Spectral Type ◽  
Dust Emission ◽  
Roche Lobe ◽  
Red Giants ◽  
Symbiotic Stars ◽  
Cool Component ◽  
Cool Star ◽  
Type D ◽  
Red Giant

In 1975 Webster and Allen (1975) divided all symbiotic stars into two groups-those in which the 1-4μm continuum show only the presence of a cool star (type S),and those in which dust emission dominates (type D). With the exception of some of yellow symbiotic stars, the dust presence in others correlates with the spectral type of their cool components. That is why one can say that S-type symbiotics contain red giants with spectral type earlier than M6-M7.At the IAU Colloq. N 7Q Allen (1982) noted that it is difficult to escape the conclusion that symbiotic stars contain normal cool giants. Nowadays it is certaiu to be correct because the modern observations of S-type symbiotic stars have not yet discovered any specific distinctions between their cool stellar components and normal red giants. At the same time it should be noted that some of these, for example, Z And, CI Cyg may be interacting binaries in which the cool component apparently fields its Roche lobe and unstable accretion of gas from the red giant onto its hot companion leads to the out bursts of the latter (Kenyon and Webbink 1984; Yudin 1987).

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