scholarly journals Ultraviolet Variability of AX Persei

1988 ◽  
Vol 103 ◽  
pp. 303-304
Author(s):  
Joanna Mikolajewska
Keyword(s):  
Optical Spectra ◽  
Radial Velocities ◽  
Roche Lobe ◽  
Emission Lines ◽  
Eclipsing Binary ◽  
Spectroscopic Observations ◽  
Photometric And Spectroscopic Observations ◽  
Red Giant

Recent photometric and spectroscopic observations suggest AX Per might be an eclipsing binary with a period of about 682 days (Kenyon 1986 and references therein). The analysis of optical spectra taken during 1979-1986 has shown periodic minima in all observed permitted lines and a lack of any periodicity in the forbidden lines (Mikolajewska 1987; Mikolajewska & lijima 1987). A comparison of the available radial velocities with these intensity variations shows that the behaviour of emission lines is consistent with the eclipse interpretation, however the minima (especially in HI and HeI) are too broad to be consistent with eclipses even by a Roche lobe filling red giant. In the following, the UV behaviour of AX Per is analysed using IUE spectra collected during the period 1979-1984.

scholarly journals Ultraviolet Variability of the Symbiotic Star AG PEG

1988 ◽  
Vol 103 ◽  
pp. 263-264
Author(s):  
D. Chochol ◽  
Z. Komárek ◽  
A. Vittone
Keyword(s):  
Optical Spectra ◽  
Radial Velocities ◽  
Roche Lobe ◽  
Emission Lines ◽  
High Dispersion ◽  
Symbiotic Star ◽  
Observational Material

Symbiotic star AG Peg consists of a hot subdwarf with a WN6 spectrum and a cool M3 giant, which is not filling its Roche lobe (Boyarchuk 1967, 1985). A detailed study of profiles, equivalent widths and radial velocities of emission lines in optical spectra allowed Hutchings et al. (1975) to conclude that a hot subluminous star approximately 1 M⊙ rotates rapidly and ejects material which streams towards the cool M giant with the mass 3-4 M⊙. UV observations seems to support this model.UV observations provided from the databank of the IUE satellite were obtained in 1978–81 by different observers. The observational material consists of 12 high dispersion SWP spectra and covers the region 1200 – 2100 A. The spectra were reduced at Trieste observatory using standard IUESIPS package. The radial velocities of emission lines were measured on tracings and corrected for the motion of Earth and satellite.

scholarly journals V 3903 Sagitarii: A Main-Sequence (07V+09V) Detached Eclipsing Binary

1993 ◽  
Vol 137 ◽  
pp. 371-373
Author(s):  
L.P.R. Vaz ◽  
N.C.S. Cunha ◽  
E.F. Vieira ◽  
M.L.M. Myrrha
Keyword(s):  
Main Sequence ◽  
Eclipsing Binary ◽  
Spectroscopic Observations ◽  
Photometric And Spectroscopic Observations ◽  
Absolute Dimensions

AbstractPhotometric and spectroscopic observations of V3903 Sgr are analyzed, and absolute dimensions (masses and radii) are determined to a precision better then 3%.

scholarly journals Call H and K Emission in the Secondary Component of U Cephei

1988 ◽  
Vol 108 ◽  
pp. 219-220
Author(s):  
Akira Okazaki ◽  
Yasuhisa Nakamura ◽  
Jun-Ichi Katahira
Keyword(s):  
Emission Lines ◽  
Secondary Component ◽  
Eclipsing Binary ◽  
Image Tube ◽  
X Ray ◽  
Spectroscopic Observations ◽  
The Third ◽  
Total Eclipse ◽  
Hot Corona ◽  
Made In

U Cephei (V = 6.8–9.0, P = 2.493 d) is an eclipsing binary consisting of a B7V primary and a G8III-IV secondary component. This binary is one of the semidetached Algol systems showing soft X-ray emission which is probably associated with a hot corona surrounding the secondary component (White and Marshall 1983).We made spectroscopic observations of U Cep with the coudé image-tube spectrograph of the 1.9-m telescope at Okayama Astrophysical Observatory on October 14, 1986. We obtained four spectrograms with a dispersion of 16 Å mm-1 covering λ λ3700—4300 Å during the primary eclipse. The first two exposures were made in a total eclipse, while the last two were slightly after the third contact. The CaII H and K emission lines appear clearly in all the spectrograms. Figure 1 represents an intensity tracing of one of these spectrograms.

scholarly journals Towards observations of Population III galaxies

2003 ◽  
Vol 212 ◽  
pp. 747-748
Author(s):  
Daniel Schaerer ◽  
Roser Pelló
Keyword(s):  
Rest Frame ◽  
Optical Spectra ◽  
Search Strategies ◽  
List Type ◽  
Type Number ◽  
Optimal Search ◽  
Spectroscopic Observations ◽  
Photometric And Spectroscopic Observations ◽  
Space Observations ◽  
Population Iii

We are undertaking various studies of primordial galaxies with the following main aims: (i)synthesize the properties of rest-frame UV-optical spectra of Population III galaxies and ‘transition objects’ between Pop III and normal starbursts;(ii)devise optimal search strategies for the detection of Pop III and related objects with ground-based and space observations;(iii)simulate photometric and spectroscopic observations of Pop III galaxies to quantify the feasibility of such studies especially for future ground-based instruments; and(iv)study the physics of Pop III and ‘transition’ galaxies and their implications on cosmology and the physics of galaxies

scholarly journals Optical and X-ray studies of three polars: RX J0859.1+0537, RX J0749.1–0549, and RX J0649.8–0737

2019 ◽  
Vol 491 (1) ◽  
pp. 201-214 ◽  
Author(s):  
Arti Joshi ◽  
J C Pandey ◽  
Ashish Raj ◽  
K P Singh ◽  
G C Anupama ◽  
...  
Keyword(s):  
White Dwarf ◽  
Optical Spectra ◽  
Emission Lines ◽  
X Ray ◽  
Long Period ◽  
Photometric And Spectroscopic Observations ◽  
High Ionization ◽  
Orbital Periods ◽  
Actual Size ◽  
Balmer Decrement

ABSTRACT We present optical photometric and spectroscopic observations, and an analysis of archival X-ray data of three polars: RX J0859.1+0537, RX J0749.1–0549, and RX J0649.8–0737. Optical light curves of these three polars reveal eclipse-like features that are deep, total, and variable in shape. The optical and X-ray modulations of RX J0859.1+0537, RX J0749.1–0549, and RX J0649.8–0737 are both found to occur at the orbital periods of 2.393 ± 0.003 h, 3.672 ± 0.001 h, and 4.347 ± 0.001 h, respectively. RX J0859.1+0537 is found to be a polar that lies in the region of the period gap, whereas RX J0749.1–0549 and RX J0649.8–0737 are found to be long-period polars above the period gap. The eclipse length is found to be 61 min for RX J0749.1–0549 in the Rband, which is the highest among the long-period eclipsing polars. The radius of the eclipsed light source is found to be more than the actual size of the white dwarf for these three systems, indicating that the eclipsed component is not only the white dwarf but also appears to include the presence of an extended accretion region. Optical spectra of these systems show the presence of high-ionization emission lines along with the strong Balmer emission lines with an inverted Balmer decrement. Cyclotron harmonics are also detected in the optical spectra from which we infer magnetic field strength of the surface of the white dwarf to be 49 ± 2 MG, 43.5 ± 1.4 MG, and 44 ± 1 MG for RX J0859.1+0537, RX J0749.1–0549, and RX J0649.8–0737, respectively.

scholarly journals The changing spectrum and orbital motion of the SMC Wolf-Rayet binary HD 5980

1995 ◽  
Vol 163 ◽  
pp. 254-255
Author(s):  
R.H. Barbá ◽  
V.S. Niemela
Keyword(s):  
Line Width ◽  
Spectral Type ◽  
Orbital Motion ◽  
Emission Lines ◽  
Secondary Component ◽  
Published Data ◽  
Remarkable Change ◽  
Eclipsing Binary ◽  
Spectroscopic Observations ◽  
Type Spectrum

Optical spectroscopic observations of the eclipsing binary WR star HD 5980 in the SMC, obtained during different epochs, show a remarkable change of the WR type spectrum from spectral type WN3-4 to WN7-8. Radial velocities of the WR emission lines from spectra obtained in August 1992, indicate an orbital motion corresponding to the secondary component which is in front of the system during the primary eclipse. We compare the RV curves and phase-dependent line-width variations observed in 1992 with previously published data.

scholarly journals Spectroscopic Observations of U Gem

1976 ◽  
Vol 73 ◽  
pp. 149-154
Author(s):  
J. I. Smak
Keyword(s):  
Binary System ◽  
Hot Spot ◽  
Primary Component ◽  
Radial Velocities ◽  
Emission Lines ◽  
Mass Ratio ◽  
Balmer Series ◽  
Gaseous Disk ◽  
Spectroscopic Observations

Radial velocities of U Gem have been measured from individual components of the emission lines of the Balmer series, Ca II K, and He 14471, originating in the gaseous disk and in the hot spot of this binary system. These new data give K1 ≅ 143 km s−1 and Vdisk sin i ≅ 530 km s−1. The resulting mass of the primary component is m1 = 1.1 ± 0.4 m⊙ and the mass-ratio m2/m1 = 0.6 ± 0.2. Radial velocities and intensities of the emission components originating in the hot spot are also discussed.

scholarly journals Hunt for Binaries with Pulsating Components

2006 ◽  
Vol 2 (S240) ◽  
pp. 697-699
Author(s):  
Olivera Latković
Keyword(s):  
Binary Stars ◽  
Binary Systems ◽  
Astronomical Observatory ◽  
Curve Analysis ◽  
Radial Velocities ◽  
Eclipsing Binary ◽  
Spectroscopic Observations

AbstractIn the frame of the collaboration of several Southern European observatories, we are examining a number of eclipsing binary systems in search for evidence of pulsating phenomena. We hope our candidate systems will be suitable for subsequent astroseismological studies. As a first step towards this end, we are analyzing spectroscopic observations of several such binary stars; these observations have been made at the National Astronomical Observatory Rozhen, Bulgaria, in the period from 2002 to 2005, and the reduction was done at the Astronomical Observatory of Belgrade, Serbia. The measurements of radial velocities and RV curve analysis are in preparation.

scholarly journals The Bq[] Evolved Massive Eclipsing Binary RY Scuti

1977 ◽  
Vol 42 ◽  
pp. 386-387
Author(s):  
F. Ciatti ◽  
A. Mammano ◽  
R. Margoni ◽  
A. Vittone ◽  
G. Strazzulla
Keyword(s):  
Advanced Stage ◽  
Eclipsing Binary ◽  
Spectroscopic Observations ◽  
Photometric And Spectroscopic Observations

Photometric and spectroscopic observations of RY Scuti are presented. These da ta indicate an advanced stage of this β Lyrae-type massive system, whose further e volution could lead to a SN-II event with the formation of a system like Cyg X-l.

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