scholarly journals High-dispersion spectroscopy of AE Aqr II: evidence of material orbiting the primary star

2021 ◽  
Author(s):  
S H Ramírez ◽  
J Echevarría
Keyword(s):  
White Dwarf ◽  
Orbital Motion ◽  
Emission Lines ◽  
High Dispersion ◽  
Primary Star ◽  
Indirect Methods ◽  
Doppler Tomography ◽  
Best Value ◽  
Hα Emission ◽  
Left Quadrant

Abstract We present a second paper of the analyses of high-dispersion spectroscopic observations of the magnetic cataclysmic variable AE Aquarii. We focus our efforts on the study of the emission lines and their radial velocities. We detect a sinusoidal behaviour, in several of the observing runs, with variable amplitudes. Of those runs presented, the velocity curve of 2000 August shows less instability in the emission material. In this case we obtain K1 = 114 ± 8 kms−1, which we take as our best value for the radial velocity of the primary. This result is consistent within 2σ with previously published values obtained using indirect methods. We interpret this consistency as observational evidence of material orbiting the rapidly-rotating primary star. We present a Doppler Tomography study, which shows that the Hα emission is primarily concentrated within a blob in the lower left quadrant; a structure similar to that predicted by the propeller model. However, for 2000 August, we find the emission centred around the position of the white dwarf, which supports the possibility of the K1 value of this run of being a valid approximation of the orbital motion of the white dwarf.

scholarly journals Spectroscopic Observations of The Be Star PHI-PER

1993 ◽  
Vol 137 ◽  
pp. 804-806
Author(s):  
Mahendra Singh ◽  
Masahiro Mon ◽  
Tomokazu Kogure ◽  
Masakazu Suzuki
Keyword(s):  
Radial Velocity ◽  
Intensity Ratio ◽  
Emission Lines ◽  
High Dispersion ◽  
Main Difficulty ◽  
Primary Star ◽  
Red Emission ◽  
Binary Nature ◽  
Spectroscopic Observations ◽  
Be Star

AbstractBased on a series of high dispersion Coude spectra taken with 188-cm telescope of Okayama Astrophysical Observatory over an extensive period of time (nearly 20 years), spectroscopic behaviours were measured and discussed. Synchronous variations of V/R (intensity ratio of violet to red emission peaksjvariability with the radial velocity curves (RV) for Balmer and Hel 3888 shell absorption lines were confirmed. Using the peak separations of the Balmer emission lines, envelope extension was also estimated. Main difficulty was found in explaining the envelope extension of the primary star of the system which overflows the Roche-lobe limit when we consider the binary nature of the system.

scholarly journals Hα Doppler Tomography of AM Her: Evidence for Bipolar Accretion

2004 ◽  
Vol 190 ◽  
pp. 274-275
Author(s):  
Christos Papadimitriou ◽  
Emilios Harlaftis
Keyword(s):  
White Dwarf ◽  
Emission Lines ◽  
Doppler Tomography ◽  
Main Pole

AbstractWe present Doppler maps of Halpha emission lines of AM Her from four differents epochs. The tomography shows a strong velocity “spot” emission at (−100,−100) km s−1 and a weaker “spot” emission at (−100,−400) km s−1 which is suggestive of bi-polar accretion onto the white dwarf with stronger emission from the main pole at phase φ=0.0.

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 The frequency of gaseous debris discs around white dwarfs

2020 ◽  
Vol 493 (2) ◽  
pp. 2127-2139 ◽  
Author(s):  
Christopher J Manser ◽  
Boris T Gänsicke ◽  
Nicola Pietro Gentile Fusillo ◽  
Richard Ashley ◽  
Elmé Breedt ◽  
...  
Keyword(s):  
White Dwarf ◽  
White Dwarfs ◽  
Signal To Noise Ratio ◽  
Infrared Emission ◽  
Sloan Digital Sky Survey ◽  
Emission Lines ◽  
Occurrence Rate ◽  
Limited Sample ◽  
Sky Survey ◽  
Gaseous Disc

ABSTRACT A total of 1–3 per cent of white dwarfs are orbited by planetary dusty debris detectable as infrared emission in excess above the white dwarf flux. In a rare subset of these systems, a gaseous disc component is also detected via emission lines of the Ca ii 8600 Å triplet, broadened by the Keplerian velocity of the disc. We present the first statistical study of the fraction of debris discs containing detectable amounts of gas in emission at white dwarfs within a magnitude and signal-to-noise ratio limited sample. We select 7705 single white dwarfs spectroscopically observed by the Sloan Digital Sky Survey (SDSS) and Gaia with magnitudes g ≤ 19. We identify five gaseous disc hosts, all of which have been previously discovered. We calculate the occurrence rate of a white dwarf hosting a debris disc detectable via Ca ii emission lines as $0.067\, \pm \, ^{0.042}_{0.025}$ per cent. This corresponds to an occurrence rate for a dusty debris disc to have an observable gaseous component in emission as 4 ± $_{2}^{4}$ per cent. Given that variability is a common feature of the emission profiles of gaseous debris discs, and the recent detection of a planetesimal orbiting within the disc of SDSS J122859.93+104032.9, we propose that gaseous components are tracers for the presence of planetesimals embedded in the discs and outline a qualitative model. We also present spectroscopy of the Ca ii triplet 8600 Å region for 20 white dwarfs hosting dusty debris discs in an attempt to identify gaseous emission. We do not detect any gaseous components in these 20 systems, consistent with the occurrence rate that we calculated.

scholarly journals The Massive Close Binary in the δ Ori A Triple System

2002 ◽  
Vol 187 ◽  
pp. 47-52
Author(s):  
James A. Harvin ◽  
Douglas R. Gies
Keyword(s):  
Cross Correlation ◽  
Short Wave ◽  
Close Binary ◽  
Full Description ◽  
High Dispersion ◽  
Orbital Elements ◽  
Primary Star ◽  
International Ultraviolet Explorer ◽  
Triple Star ◽  
Massive Close Binary

AbstractWe present an analysis of short-wave, high-dispersion ultraviolet spectra of the triple star δ Ori A from the International Ultraviolet Explorer Satellite’s (IUE) Final Archive. These spectra were cross-correlated against AE Aur to find the components’ radial velocities, which were then used to produce the system’s orbital elements. The long-period tertiary star in the δ Ori A system was not seen in the resulting cross-correlation functions (CCFs). The close binary’s eclipses allow the orbit’s inclination to be estimated by modeling of its Hipparcos light curve. The primary star appears to have a mass of 11.2 M⊙ and the secondary seems to have a mass of 5.6 M⊙, both of which are about 1/3 of the expected values for stars of their MK types. Although we expected the massive close binary in the δ Ori A system to be a pre-Roche lobe overflow (RLOF) system, these masses appear to require that it be a post-RLOF system. The full description of this work, including the tomographic separation of the spectra for the close binary’s components, appears in Harvin et al. (2002).

scholarly journals New Wolf-Rayet Binaries

1991 ◽  
Vol 143 ◽  
pp. 201-206 ◽  
Author(s):  
Virpi S. Niemela
Keyword(s):  
Radial Velocity ◽  
Binary Systems ◽  
Orbital Motion ◽  
Elliptic Orbit ◽  
Emission Lines

Preliminary radial velocity orbits are presented for three binary systems containing Wolf-Rayet stars, namely Sk-71° 34 in the LMC, and WR8 and WR98 in our galaxy. Sk-71° 34 is found to be a WN3 + O6 double-lined binary with an elliptic orbit of period about 34 days. WR8 and WR98 both have WN type spectra with carbon lines. In WR8 the N and C lines appear to move in antiphase, while in WR98 all emission lines have the same orbital motion.

scholarly journals Colliding Stellar Winds in O-type Close Binary Systems

1992 ◽  
Vol 135 ◽  
pp. 146-148
Author(s):  
D.R. Gies ◽  
M.S. Wiggs
Keyword(s):  
Binary Systems ◽  
Optical Emission ◽  
Emission Lines ◽  
Optical Observations ◽  
Close Binary ◽  
High Dispersion ◽  
Stellar Winds ◽  
Close Binary Systems ◽  
Circumstellar Gas ◽  
The Individual

In close binary systems of O-type stars, the individual stellar winds will collide between the stars to form shock fronts (Stevens et al. 1992). Binaries with equally luminous stars will have winds of comparable strength, and the shock will occur near the mid-plane between the stars, but in binaries of unequal luminosity, the interaction will occur along a bow shock wrapped around the star with the weaker wind. The presence of the shock region can be detected through excess X-ray emission (Chlebowski & Garmany 1990), and orbital phase-related variations in the UV P Cygni lines (Shore & Brown 1988) and optical emission lines (formed in high density regions of circumstellar gas).We have begun a search for colliding winds through a study of the optical emission lines and UV P Cygni lines in four massive binaries, AO Cas (Gies & Wiggs 1991), Plaskett’s star = HD 47129 (Wiggs & Gies 1992), 29 UW CMa and ι Ori. The optical observations consist of high S/N spectra of the Hα and He I λ6678 region obtained with the University of Texas McDonald Observatory 2.1-m telescope and coudé Reticon system. The UV observations were culled from archival IUE high dispersion spectra of several P Cygni features (N V λ1240, Si IV λ1400, C IV λ1550).

scholarly journals A low-mass stellar companion to the young variable star RZ Psc

2020 ◽  
Vol 496 (1) ◽  
pp. L75-L79
Author(s):  
Grant M Kennedy ◽  
Christian Ginski ◽  
Matthew A Kenworthy ◽  
Myriam Benisty ◽  
Thomas Henning ◽  
...  
Keyword(s):  
Linear Polarization ◽  
Variable Star ◽  
Orbital Motion ◽  
Orbital Plane ◽  
Position Angle ◽  
Circumstellar Dust ◽  
Primary Star ◽  
Infrared Excess ◽  
Low Mass ◽  
Rz Psc

ABSTRACT RZ Psc is a young Sun-like star with a bright and warm infrared excess that is occasionally dimmed significantly by circumstellar dust structures. Optical depth arguments suggest that the dimming events do not probe a typical sightline through the circumstellar dust, and are instead caused by structures that appear above an optically thick mid-plane. This system may therefore be similar to systems where an outer disc is shadowed by material closer to the star. Here, we report the discovery that RZ Psc hosts a $0.12\, \mathrm{ M}_\odot$ companion at a projected separation of 23 au. We conclude that the disc must orbit the primary star. While we do not detect orbital motion, comparison of the angle of linear polarization of the primary with the companion’s on-sky position angle provides circumstantial evidence that the companion and disc may not share the same orbital plane. Whether the companion severely disrupts the disc, truncates it, or has little effect at all will require further observations of both the companion and disc.

scholarly journals A search for s-process elements in extremely metal-poor halo planetary nebulae

2009 ◽  
Vol 5 (S265) ◽  
pp. 77-78
Author(s):  
Masaaki Otsuka ◽  
Akito Tajitsu ◽  
Hideyuki Izumiura ◽  
Siek Hyung
Keyword(s):  
Planetary Nebulae ◽  
Emission Lines ◽  
High Dispersion ◽  
C And N ◽  
Binary Evolution ◽  
Process Elements

AbstractWe have performed deep high-dispersion spectroscopy to examine enhancement of s-process elements in the exremely metal-poor ([Ar/H]~−2.1) halo planetary nebulae H4-1 and BoBn1 using the 8.2-m Subaru telescope/High-Dispersion Spectrograph (HDS). We have detected several emission lines of s-process elements in H4-1 and BoBn1, and we have found that the enhancement of heavy s-process elements in these objects is comparable with that in s-process enhanced CEMP stars with [Fe/H]>−2.5. The C- and N-rich abundances of H4-1 and BoBn1 might be explained by binary evolution models. We have detected 5 fluorine lines in BoBn1. The re-estimated F abundance using these lines is [F/H]=+1.4±0.1.

scholarly journals The “Gravitational Lens” 3C 321: A Remarkable Impostor

1987 ◽  
Vol 124 ◽  
pp. 761-765
Author(s):  
Alexei V. Filippenko
Keyword(s):  
Radio Galaxy ◽  
Line Emission ◽  
Careful Analysis ◽  
Gravitational Lens ◽  
Emission Lines ◽  
Optical Data ◽  
High Ionization ◽  
Spectrum Radio ◽  
Hα Emission

Recent observations of the radio galaxy 3C 321 are presented. The optical nucleus consists of two components (A, B), separated by ∼ 4″ (∼ 6 kpc), whose low-resolution spectra strongly resemble those of high-ionization type 2 Seyfert nuclei. The relative intensities of the emission lines differ in A and B by less than 1%, and their profiles are almost identical. 3C 321 appears to be a convincing example of a gravitationally lensed object.Careful analysis of high-quality radio and optical data, however, reveals that the system is almost certainly not a lens. The equivalent widths of the emission lines are roughly twice as high in B than in A, and there are significant spatial offsets between regions of bright continuum and line emission. A slight, but fundamental, difference is visible in the two Hα emission profiles. The radial velocities of A and B are discrepant by 31 ± 10 km s−1. Finally, component A is nearly coincident with a flat-spectrum radio core, whereas B is next to an extended, steep-spectrum knot of radio emission.This object should serve as a warning to lens hunters: beware of impostors, whose true properties may be difficult to ascertain without extensive optical and radio observations.

Sign in / Sign up

Export Citation Format

Share Document