scholarly journals 500 - 3200 Å Observations of the Interacting Binary Stars V356 Sgr and β Lyr

1989 ◽  
Vol 107 ◽  
pp. 85-94
Author(s):  
R. S. Polidan
Keyword(s):  
Binary Stars ◽  
Cataclysmic Variables ◽  
Circumstellar Matter ◽  
Emission Lines ◽  
High Dispersion ◽  
Total Strength ◽  
Uv Emission ◽  
Flux Level ◽  
Orbital Modulation ◽  
Ultraviolet Observations

AbstractIn this paper we present new results from the Voyager ultraviolet spectrometers and the IUE spacecraft on V356 Sgr and β Lyr. The V356 Sgr observations cover, in detail, two eclipses and include one IUE high dispersion SWP image. During both eclipses the total strength of the UV emission lines were found to be invariant. Also, an uneclipsed UV continuum was detected at wavelengths shorter than 1600 Å. The IUE high dispersion SWP spectrum revealed that the emission lines are extremely broad, almost symmetrical lines with weak, slightly blue shifted absorption components. No evidence of carbon is seen in the emission or absorption spectrum of V356 Sgr in eclipse. A model for the origin of the circumstellar matter in this binary system is presented. The Voyager ultraviolet observations of β Lyr show a strong far-UV continuum that is detectable down to 912 Å The far-UV continuum flux level was variable on time scales shorter than the orbital period and displayed no obvious orbital modulation or eclipses. The spectral shape of the far-UV continuum closely resembles that of a UX UMa type cataclysmic variable. On 16 August 1985 an rapid brightening of the far-UV continuum was observed which was also reminiscent of cataclysmic variables. Analysis of the β Lyr data suggest that the central object must be small, with a radius on the order of 1 R⊙ or less.

scholarly journals Ultraviolet Observations of Cataclysmic Variables

1987 ◽  
Vol 93 ◽  
pp. 205-205 ◽  
Author(s):  
F. Verbunt
Keyword(s):  
Orbital Period ◽  
Cataclysmic Variables ◽  
Type Systems ◽  
Terminal Velocity ◽  
Dwarf Novae ◽  
Preliminary Results ◽  
System Type ◽  
International Ultraviolet Explorer ◽  
Flux Level ◽  
Ultraviolet Observations

AbstractThe preliminary results of the analysis of more than 1000 spectra of cataclysmic variables in the archive of the International Ultraviolet Explorer were presented at the meeting. To characterize the slope of the spectra I use F = log(f1460Å/f2880Å). For most spectra F lies between 0.2 and 0.7. No correlation of F with orbital period, inclination, system type or (for dwarf novae) length of the interoutburst interval are found, apart from somewhat lower values of F for DQ Her type systems. Out of 16 dwarf novae for which spectra both at outburst maximum and minimum are available 11 show no large difference in F between maximum and minimum, and in 5 F declines with the flux level. Out of 6 dwarf novae 5 show very red spectra during the rise to maximum, and 1 shows slopes during rise similar to those during decline.In the ultraviolet resonance lines, due to a wind from the disc, no correlation is found between inclination and terminal velocity.

scholarly journals A stellar census in globular clusters with MUSE: A spectral catalogue of emission-line sources

2019 ◽  
Vol 631 ◽  
pp. A118 ◽  
Author(s):  
Fabian Göttgens ◽  
Tim-Oliver Husser ◽  
Sebastian Kamann ◽  
Stefan Dreizler ◽  
Benjamin Giesers ◽  
...  
Keyword(s):  
Emission Line ◽  
Binary Stars ◽  
Globular Clusters ◽  
Cataclysmic Variables ◽  
Variable Stars ◽  
Emission Lines ◽  
Data Set ◽  
Stellar Spectra ◽  
X Ray ◽  
Emission Line Galaxies

Aims. Globular clusters produce many exotic stars due to a much higher frequency of dynamical interactions in their dense stellar environments. Some of these objects were observed together with several hundred thousand other stars in our MUSE survey of 26 Galactic globular clusters. Assuming that at least a few exotic stars have exotic spectra (i.e. spectra that contain emission lines), we can use this large spectroscopic data set of over a million stellar spectra as a blind survey to detect stellar exotica in globular clusters. Methods. To detect emission lines in each spectrum, we modelled the expected shape of an emission line as a Gaussian curve. This template was used for matched filtering on the differences between each observed 1D spectrum and its fitted spectral model. The spectra with the most significant detections of Hα emission are checked visually and cross-matched with published catalogues. Results. We find 156 stars with Hα emission, including several known cataclysmic variables (CV) and two new CVs, pulsating variable stars, eclipsing binary stars, the optical counterpart of a known black hole, several probable sub-subgiants and red stragglers, and 21 background emission-line galaxies. We find possible optical counterparts to 39 X-ray sources, as we detected Hα emission in several spectra of stars that are close to known positions of Chandra X-ray sources. This spectral catalogue can be used to supplement existing or future X-ray or radio observations with spectra of potential optical counterparts to classify the sources.

scholarly journals New Observations of the Old Magnetic Nova GQ Muscae

2014 ◽  
Vol 23 (1) ◽  
pp. 1-7
Author(s):  
W. Narloch ◽  
J. Kaluzny ◽  
W. Krzeminski ◽  
W. Pych ◽  
M. Rozyczka ◽  
...  
Keyword(s):  
Orbital Period ◽  
Time Scale ◽  
Cataclysmic Variables ◽  
Emission Lines ◽  
Total Amplitude ◽  
Broad Emission ◽  
Photometric Observations ◽  
Bright Object ◽  
Orbital Modulation ◽  
Magnetic Cataclysmic Variables

AbstractPhotometric observations of GQ Mus performed between 1992 and 2011 are reported. We find that the total amplitude of the orbital modulation of its brightness decreased from ~ 0.9 mag in 1992 to ~ 0.2 mag in 2010, becoming comparable to the amplitude of chaotic flickering on a time scale of several minutes. Optical spectra obtained in 2001 and 2012 indicate continuing activity of GQ Mus. The spectra show broad emission lines of He II and H I typical for magnetic cataclysmic variables. The nova was found to be an UV-bright object in 2001 and 2012. We also show that the orbital period of GQ Mus has been constant between 1989 and 2010–2011.

scholarly journals Probing the ISM of Heiiλ1640 emitters at z = 2–4 via MUSE

2019 ◽  
Vol 15 (S341) ◽  
pp. 235-239
Author(s):  
Themiya Nanayakkara ◽  
Jarle Brinchmann ◽  
Keyword(s):  
Emission Line ◽  
Stellar Evolution ◽  
Binary Stars ◽  
Stellar Population ◽  
Emission Lines ◽  
Similar Distribution ◽  
Metal Free ◽  
Uv Emission ◽  
Absolute Magnitudes ◽  
Line Analysis

AbstractHeiiλ1640 emission in the absence of other metal lines is the most sought-after emission line to detect and characterize metal free stellar populations. However, even recent stellar population models with sophisticated treatment of stellar evolution also lack sufficient He+ ionising photons to reproduce observed He 0.1em ii fluxes. We use VLT/MUSE GTO observations to compile a catalogue of 15 z ∼ 2–4 He ii λ1640 emitters from ∼10–30 hour pointings. We show that both He ii λ1640 detections and non-detections occupy similar distribution in UV absolute magnitudes. Rest-UV emission line analysis of our sample shows that the emission lines of our He ii λ1640 emitters are driven by star-formation in solar to moderately sub-solar (∼1/20th) metallicity conditions. However, we find that even after considering effects from binary stars, we are unable to reproduce the He ii λ1640 equivalent widths. Alternative mechanisms are necessary to compensate for the missing He+ ionising photons.

scholarly journals Observations of CNO Processed Matter in Massive Interacting Binary Systems

1992 ◽  
Vol 151 ◽  
pp. 351-354
Author(s):  
Ronald S. Polidan ◽  
Richard A. Wade
Keyword(s):  
Mass Transfer ◽  
Emission Spectrum ◽  
Carbon Emission ◽  
Binary Systems ◽  
Emission Lines ◽  
Emission Analysis ◽  
Uv Emission ◽  
Ultraviolet Observations

Ultraviolet observations for nine massive Algol systems (DH Her, TU Mon, AU Mon, Z Ori, RY Per, IZ Per, V356 Sgr, RZ Sct and ET Tau) obtained during their primary eclipses with the IUE spacecraft are discussed. Four systems, AU Mon, Z Ori, IZ Per, and RZ Sct, yielded no useful data on the presence of UV emission lines. Four binary systems DH Her, TU Mon, RY Per, and V356 Sgr, displayed a prominent emission spectrum with the notable exception of carbon lines; only one of the studied systems, ET Tau, showed carbon emission. Analysis of these data strongly supports the suggestion that the lack of carbon emission lines in these systems is the product of an inherent carbon deficiency in the transferred material and not due to any ionization effects in the gas. This carbon deficiency is the result of the CNO processed layers of the secondary being exposed as a result of mass transfer. The IUE data on TU Mon also indicates that this system undergoes a total, rather than partial, eclipse.

scholarly journals X-ray and UV emission of the ultrashort-period, low-mass eclipsing binary system BX Trianguli

2018 ◽  
Vol 619 ◽  
pp. A138
Author(s):  
V. Perdelwitz ◽  
S. Czesla ◽  
J. Robrade ◽  
T. Pribulla ◽  
J. H. M. M. Schmitt
Keyword(s):  
Binary System ◽  
Light Curve ◽  
Binary Systems ◽  
Uv Light ◽  
Close Binary ◽  
Eclipsing Binary ◽  
X Ray ◽  
Uv Emission ◽  
Low Mass ◽  
Orbital Modulation

Context.Close binary systems provide an excellent tool for determining stellar parameters such as radii and masses with a high degree of precision. Due to the high rotational velocities, most of these systems exhibit strong signs of magnetic activity, postulated to be the underlying reason for radius inflation in many of the components. Aims.We extend the sample of low-mass binary systems with well-known X-ray properties. Methods.We analyze data from a singular XMM-Newton pointing of the close, low-mass eclipsing binary system BX Tri. The UV light curve was modeled with the eclipsing binary modeling tool PHOEBE and data acquired with the EPIC cameras was analyzed to search for hints of orbital modulation. Results.We find clear evidence of orbital modulation in the UV light curve and show that PHOEBE is fully capable of modeling data within this wavelength range. Comparison to a theoretical flux prediction based on PHOENIX models shows that the majority of UV emission is of photospheric origin. While the X-ray light curve does exhibit strong variations, the signal-to-noise ratio of the observation is insufficient for a clear detection of signs of orbital modulation. There is evidence of a Neupert-like correlation between UV and X-ray data.

scholarly journals X-Ray Emission from Flare Stars

1983 ◽  
Vol 71 ◽  
pp. 125-129
Author(s):  
P.C. Agrawal ◽  
A.R. Rao ◽  
B.V. Sreekantan
Keyword(s):  
Emission Lines ◽  
Quiescent State ◽  
X Ray ◽  
Uv Emission ◽  
Chromospheric Emission ◽  
Flare Stars ◽  
Einstein Observatory

Flare stars are a group of mostly dMe stars, which show intense flaring activity in the optical as well as in the radio and X-ray bands. These stars are characterized by the presence of chromospheric emission lines like % and Call H and K which are present even during the quiescent state. The presence of transition regions and coronae have been inferred from the detection of UV emission lines like NV, CIV, SiIV etc. with IUE and X-ray observations made with the Einstein Observatory. We report here X-ray observations of flare stars made with Einstein to measure their coronal X-ray emission during the quiescent state.

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.

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