OPTICAL SPECTROSCOPY OF SYMBIOTIC STAR EG And. Hα ORBITAL VARIABILITIES

The emission and forbidden lines in quasars

\n \nWe find that the ROSAT source <ext-link ext-link-type="aoi">1RXS J105010.3-140431</ext-link> is a\ncataclysmic variable with orbital period of 88.6 min and a spectrum\nclosely resembling WZ Sge. In particular, emission lines are flanked by\nStark-broadened absorption wings probably originating in the photosphere\nof a compact object. The Balmer absorption lines can be modeled by the\nspectrum of a DA white dwarf with $13 000 &lt; T_{\\rm eff} &lt; 24 000$ K.\nThe strong absorption lines allowed us to obtain direct radial velocities\nof the white dwarf using the cross-correlation technique. We find an\nextremely low white dwarf radial velocity half amplitude, $K_{\\rm wd} = 4\n\\pm 1$ km s-1. This is consistent with the upper limit obtained from\nthe Hα emission line wing $K &lt; 20$ km s-1. The corresponding\nmass function is incompatible with a main sequence secondary, but is\ncompatible with a post orbital period minimum cataclysmic variable with a\nbrown dwarf-like secondary. The formal solution gives a secondary mass of\n10-20 Jovian masses. Doppler maps for the emission lines and the\nhypothesis of black-body emission indicate a steady state ($T \\sim\nr^{-3/4}$) accretion disk mainly emitting in Hα and an optically\nthicker hotspot with a strong contribution to the higher order Balmer\nlines and He<sc>I</sc> 5875. As in other long cycle length dwarf novae,\nevidence for inner disk removal is found from the analysis of the emission lines. \n \n

Aims. We aim to confirm whether the eclipsing cataclysmic variable (CV) V902 Mon is an intermediate polar (IP), to characterise its X-ray spectrum and flux, and to refine its orbital ephemeris and spin period. Methods. We performed spectrographic observations of V902 Mon in 2016 with the 2.2 m Calar Alto telescope, and X-ray photometry and spectroscopy with XMM-Newton in October 2017. This data was supplemented by several years of AAVSO visual photometry. Results. We confirmed V902 Mon as an IP based on detecting the spin period, which has a value of 2208 s, at multiple epochs. Spectroscopy of the donor star and Gaia parallax yield a distance of 3.5−0.9+1.3 kpc, suggesting an X-ray luminosity one or two orders of magnitude lower than the 1033 erg s−1 typical of previously known IPs. The X-ray to optical flux ratio is also very low. The inclination of the system is more than 79°, and is most likely a value of around 82°. We have refined the eclipse ephemeris, stable over 14 000 cycles. The Hα line is present throughout the orbital cycle and is clearly present during eclipse, suggesting an origin distant from the white dwarf, and shows radial velocity variations at the orbital period. The amplitude and overall recessional velocity seem inconsistent with an origin in the disc. The XMM-Newton observation reveals a partially absorbed plasma model typical of magnetic CVs, that has a fluorescent iron line at 6.4 keV showing a large equivalent width of 1.4 keV. Conclusions. V902 Mon is an IP, and probably a member of the hypothesized X-ray underluminous class of IPs. It is likely to be a disc accretor, although the radial velocity behaviour of the Hα line remains puzzling. The large equivalent width of the fluorescent iron line, the small FX/Fopt ratio, and the only marginal detection of X-ray eclipses suggests that the X-ray emission arises from scattering.

Aims. We investigate the formation of X-ray emission lines in the wind of the Wolf-Rayet (WR) companion in Cyg X-3 by analyzing their orbital dynamics using Chandra High Energy Transmission Grating (HEG) observations during a hypersoft state. Our goal is to constrain the X-ray transparency of the recently discovered funnel-like structure surrounding the compact star, as revealed by X-ray polarimetry. Methods. We analysed Chandra/HEG observations and measured radial velocities and emission line intensities as a function of orbital phase for six emission lines: Si XIV 6.184 Å, S XVI 4.734 Å, Ar XVIII 3.731 Å, Ca XX 3.018 Å, Fe XXV 1.859 Å, and Fe XXVI 1.778 Å. We constructed radial velocity and emission intensity light curves for these lines using ten phase bins, which allowed us to investigate their orbital variability using a simple spherical WR-wind model. Results. All lines exhibit sinusoidal orbital modulation, with the velocity amplitude generally increasing and the orbital phase with the highest blueshift generally decreasing for ions with a higher ionisation potential. The Fe XXVI-line displays velocity extremes at phase 0.25 (blueshift) and 0.75 (redshift), with a velocity amplitude of ~500 km/s, indicating that the line-emitting region is close to the compact component (disc or corona) and thus reflects the orbital motion. The Fe XXV-line shows a complex behaviour that cannot be fully resolved with the Chandra/HEG resolution. Other lines display velocity extremes scattered around phase 0.5 (blueshift) and 0.0 (redshift), with velocity amplitudes of 100–300 km/s, suggesting their origin in the WR stellar wind between the two components. Conclusions. The Fe XXVI-line originates in the disc or corona of the compact object and can be used to constrain the system masses (Appendix A). The origin of the Fe XXV-line remains uncertain due to the limitations of Chandra/HEG resolution. The other lines formed in the WR-wind between the component stars, likely above the orbital plane along ionisation ξ-surfaces. Parts of the emission lines of Ar XVIII and Ca XX originated around the compact star. The wind-related component of the Ca XX line formed closest to the ionizing source (the compact star) due to its highest ionisation potential. The recent polarisation funnel-modelling is consistent with the present results during the hypersoft state.

Extensive photometric and spectroscopic observations have been obtained for HS 1136+6646. The observations reveal a newly formed post–common-envelope binary system containing a hot ~DAO.5 primary and a highly irradiated secondary. HS 1136+6646 is the most extreme example yet of a class of short-period hot H-rich white dwarfs with K–M companion systems such as V471 Tau and Feige 24. HS 1136+6646 is a double-line spectroscopic binary showing emission lines of H I, He II, C II, Ca II, and Mg II, due in part to irradiation of the K7 V secondary by the hot white dwarf. Echelle spectra reveal the hydrogen emission lines to be double-peaked with widths of ~200 km s-1, raising the possibility that emission from an optically thin disk may also contribute. The emission lines are observed to disappear near the inferior conjunction. An orbital period of 0.83607 ± 0.00003 days has been determined through the phasing of radial velocities, emission-line equivalent widths, and photometric measurements spanning a range of 24 months. Radial velocity measurements yield an amplitude of KWD = 69 ± 2 km s-1 for the white dwarf and KK7V = 115 ± 1 km s-1 for the secondary star. In addition to orbital variations, photometric measurements have also revealed a low-amplitude modulation with a period of 113.13 minutes and a semiamplitude of 0.0093 mag. These short-period modulations are possibly associated with the rotation of the white dwarf. From fits of the Balmer line profiles, the white dwarf is estimated to have an effective temperature and gravity of ~70,000 K and log g ~ 7.75, respectively. However, this optically derived temperature is difficult to reconcile with the far-UV spectrum of the Lyman line region. Far Ultraviolet Spectroscopic Explorer spectra show the presence of O VI absorption lines and a spectral energy distribution whose slope persists nearly to the Lyman limit. The extremely high temperature of the white dwarf, from both optical and UV measurements, indicates that the binary system is one of the earliest post–common-envelope objects known, having an age around 7.7 × 105 yr. Although the spectrum of the secondary star is best represented by a K7 V star, indications are that the star may be overly luminous for its mass.

Aims. The aims of our study are to improve the orbital elements of the giant and to derive the spectroscopic orbit for the white dwarf companion of the symbiotic system RS Oph. Spectral variations related to the 2006 outburst are also studied. Methods. We performed an analysis of about seventy optical and near infrared spectra of RS Oph that were acquired between 1998 and June 2008. The spectroscopic orbits were obtained by measuring the radial velocities of the cool component absorption lines and the broad Hα emission wings, which seem to be associated with the hot component. A set of cF-type absorption lines were also analyzed for a possible connection with the hot component motion. Results. A new period of 453.6 days and a mass ratio, q = M g /M h = 0.59 ± 0.05 were determined. Assuming a massive white dwarf as the hot component (M h = 1.2-1.4 M ⊙ ) the red giant mass is Mg = 0.68-0.80 M ⊙ and the orbit inclination, i = 49°-52°. The cF-type lines are not associated with either binary component, and are most likely formed in the material streaming towards the hot component. We also confirm the presence of the LiI doublet in RS Oph and its radial velocities fit very well to the M-giant radial velocity curve. Regardless of the mechanism involved to produce lithium, its origin is most likely from within the cool giant rather than material captured by the giant at the time of the nova explosion. The quiescent spectra reveal a correlation of the H I and He I emission line fluxes with the monochromatic magnitudes at 4800 A, indicating that the hot component activity is responsible for those flux variations. We also discuss the spectral characteristics around 54-55 and 240 days after the 2006 outburst. In April 2006 most of the emission lines present a broad pedestal with a strong and narrow component at about -20 km s -1 and two other extended emission components at -200 and +150 km s -1 . These components could originate in a bipolar gas outflow supporting the model of a bipolar shock-heated shell expanding through the cool component wind perpendicularly to the binary orbital plane. Our observations also indicate that the cF absorption system was disrupted during the outburst, and restored about 240 days after the outburst, which is consistent with the resumption of accretion.

Late-type stars are generally characterized by the chromospheric structure showing active phenomena observable by the formation of emission lines and emission of X-ray and UV radiations. In the optical region, most ubiquitous emission lines are CaII H, K lines, while Hα line appears in fully developed chromospheres. In this section we consider the basic chromospheric activities by focusing to the CaII H, K emission lines.

SS Cygni was found by Joy (1956) to be a spectroscopic binary with an orbital period of about 6-1/2 hours. At minimum light it has mv=12 and is the brightest member of the dwarf nova class of variables. The minimum light spectrum reveals faint, narrow absorption lines of a G- or K-type star along with strong, broad emission lines of hydrogen, helium, and calcium which are produced by an accretion disk surrounding a white dwarf star. Joy’s radial velocities were not very accurate. Nevertheless, he was able to estimate the orbital elements, finding 115 km/s for the absorption line K-velocity and 122 km/s for the emission line K-velocity. In addition, he derived an orbital period of 0276244. Later minimum light observations by Walker and Chincarini (1968) were too few to be able to improve the orbital elements. Kiplinger (1979) refined the emission line radial velocities but was not able to remeasure the faint absorption line spectrum. This paper presents new radial velocity measurements of both the emission and absorption line spectra of SS Cygni at minimum light, and is the first thorough investigation of this star’s radial velocity variations in more than 20 years. The accuracy of the radial velocity curves has been greatly improved. We also find that Joy’s orbital period is in error by nearly two minutes.

Time-resolved lUE observations of the asynchronous polar BY Cam (H0538 +608) over a period of 11 days show that the N V 1240 Å emission-line velocity varies on the orbital period, with an amplitude of 368±27 km s<SUP>-1</SUP>. The N V flux also varies on the orbital period, with maximum flux corresponding to maximum blue-shift. This behavior is seen in He II 1640 Å as well, although with a smaller velocity amplitude (244±26 km s<SUP>-1</SUP>). Variation on the orbital (rather than the white dwarf spin) period implies that the emission must originate outside the magnetosphere of the white dwarf, in the accretion stream, the heated face of the secondary, or some combination of the two. The rise, peak, and fall in line emission take place over ∼0.3 of an orbit, constraining models of the system geometry; we discuss a number of potential explanations for the observed phenomena, including optically thick (in the lines) emission from the accretion stream, occultation of the emission region by the secondary, and combinations of the two processes. We also propose an alternative scenario, in which X-ray illumination from the environment of the white dwarf gives rise to anisotropic line emission from the accretion stream. Ultraviolet continuum intensities on different nights appeared to be in either low or high flux states; we obtained three nights of optical photometry during the same time period, and the optical light curves corresponding to the high and low flux states were distinct, supporting the idea that the pattern of accretion flow changes. Finally, we note that spectroscopic attempts to observe Na I λλ8183, 8194 in the photosphere of the secondary were not successful.

We have made extensive spectroscopic and photometric observations of PG 1224+309, a close containing a DA white dwarf primary and an M4+ secondary. The Hα line is in emission due to irradiation of the M star by the hot white dwarf and is seen to vary around the orbit. From the radial velocities of the Hα line we derive a period of P = 0.258689 ± 0.000004 days and a semiamplitude of KHα = 160 ± 8 km s-1. We estimate a correction ΔK = 21 ± 2 km s-1, where KM = KHα + ΔK. Radial velocity variations of the white dwarf reveal a semiamplitude of KWD = 112 ± 14 km s-1. The blue spectrum of the white dwarf is well fitted by a synthetic spectrum having Teff = 29,300 K and log g = 7.38. The white dwarf contributes 97% of the light at 4500 A and virtually all of the light blueward of 3800 A. No eclipses are observed. The mass inferred for the white dwarf depends on the assumed mass of the thin residual hydrogen envelope: 0.40 M⊙ ≤ MWD ≤ 0.45 M⊙ for hydrogen masses of 0 M⊙ ≤ MH ≤ 4 × 10-4 M⊙. We argue that the mass of the white dwarf is closer to 0.45 M⊙; hence, it appears that the white dwarf has a relatively large residual hydrogen envelope. The mass of the M star is then MM = 0.28 ± 0.05 M⊙, and the inclination is i = 77° ± 7°. We discuss briefly how PG 1224+309 may be used to constrain theories of close star evolution and the past and future histories of PG 1224+309 itself. The star is both a post–common envelope star and a pre–cataclysmic binary star. Mass transfer by Roche lobe overflow should commence in about 1010 yr.

view Abstract Citations (9) References (11) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS 2A 0311-227 (EF Eri) : radial velocities of two emission line components. Young, P. ; Schneider, D. P. ; Sargent, W. L. W. ; Boksenberg, A. Abstract The magnetic binary 2A 0311-227 is observed for more than three orbits on each of two nights with 1 A spectral resolution and 120 s temporal resolution. The radial velocity variations of the strong Balmer, He I, and He II emission lines in the region 4110-5050 A are investigated. It is noted that the emission lines are distinctly from cycle to cycle. For approximately 50% of the time, the lines consist of a single broad component (sometimes with hints of substructure) phased with the 81 minute orbital period. At other times, a second 'sharp' emission component appears in all lines, most notably in He II 4686 A. The sharp component possesses an 81 minute radial velocity period, with K equal to 600 km/s. It lags the broad component in phase by 55 deg. Other components are seen transiently but do not reproduce from cycle to cycle, including a high velocity component observed at +1200 km/s. It is noted that the multiple emission components cannot be due to magnetic effects and that the sharp component has too large a velocity to represent orbital motion. Publication: The Astrophysical Journal Pub Date: January 1982 DOI: 10.1086/159553 Bibcode: 1982ApJ...252..269Y Keywords: Binary Stars; Magnetic Stars; Radial Velocity; Spectral Line Width; Stellar Spectra; Balmer Series; Emission Spectra; H Lines; Helium; Light Curve; Astrophysics full text sources ADS | data products SIMBAD (4)

We report the first time-resolved photometric and spectroscopic optical observations of the X-ray source RX J2133.7+5107, identified in the ROSAT survey. A clear persistent optical light pulsation is discovered with fast photometry at a period of P_{omega} =(570.823 +/-0.013) s which we associate with the spin period of an accreting white dwarf. Radial velocity curves of the strong emission lines show modulation with a period of P_{Omega} =(7.193 +/- 0.016) hr, identified as the orbital period. These observations establish that the source is a member of the intermediate polar class (IPs) of magnetic cataclysmic variables. With only 4 IPs with longer orbital periods, RX J2133.7+5107 is among the widest systems. It is a unique IP with an orbital period in the middle of the so-called (6-10)hr IP gap and it shows a significant degree of asynchronism with a ratio P_{omega}/P_{Omega} of 0.02. When attributed to the motion of the white dwarf, the emission lines orbital modulation yields a mass function of f_m = (1.05 +/- 0.21) 10^{-2} Msun which, for a probable inclination i < 45 deg and a white dwarf mass M_{wd} = (0.6-1.0) Msun, corresponds to a secondary mass M_{s} > (0.27-0.37) Msun.

We present the results of a detailed spectroscopic investigation of the supergiant HD 207260 (A2 Iae), based on high-resolution echelle spectra obtained in 2018 with the 2-meter telescope at the Shamakhi Astrophysical Observatory. The focus is on the variability of the Hα line, which exhibits a complex and variable profile, consisting of both an absorption and an emission component. The intensity of the emission component and its radial velocity were found to vary significantly across different epochs. These changes were accompanied by synchronous variations in the radial velocity of the absorption and in the equivalent width of the line. Such behavior suggests a dynamical origin for the emission component, possibly related to instabilities in the upper atmosphere or episodic mass loss processes. Fourier analysis of the radial velocity variations reveals with an approximate of 35–40 days. This periodicity is consistent with the presence of radial or non-radial pulsations, which may drive structured outflows in the upper layers of the stellar atmosphere. It is assumed that the change in the Hα line profile, the change in the radial velocity and the equivalent width of the absorption and emission components of the Hα line profile occur as a result of the interaction of the stellar atmosphere with the circumstellar envelope as a result of the pulsation of the star.

The identification and study of the optical counterpart of the ROSAT-discovered AM Her system RX J2157.5+0855 is reported. We present high time-resolution spectrophotometric, spectropolarimetric, and multicolor CCD-photometric observations of this polar obtained when the system was actively accreting. The 3.375 hr orbital period of the system places it among a few long-period AM Her objects. The emission lines clearly reveal the presence of at least two different line components with different widths and radial velocity variations. The Balmer emission lines contain significant contribution from the X/UV-illuminated hemisphere of the secondary star. The Hα line is deblended into two components, which we identify with the secondary star and the accretion stream. The circular polarization unambiguously confirms the magnetic nature of this newly discovered cataclysmic variable with ≈20 MG strength deduced by cyclotron emission modeling. Combining radial velocity and light curves with polarization variations provides additional information about the system geometry.

view Abstract Citations (36) References (55) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Spectroscopic, Orbital, and Physical Properties of the Binary Feige 24 and Detection of Transient He II Absorption in the System Vennes, S. ; Thorstensen, J. R. Abstract We have obtained new high-dispersion optical spectroscopy at Kitt Peak National Observatory (KPNO) and new International Ultraviolet Explorer (IUE) spectroscopy of the white dwarf+red dwarf binary system Feige 24. The optical range shows a composite DA+dM spectrum, together with H I Balmer and He I emission. The orbital phase dependence of the emission shows that it results from extreme ultraviolet (EUV) light reprocessing in the red dwarf upper atmosphere. The systems close enough and hot enough to show this reprocessing signature only recently emerged from common-envelope evolution. The ultraviolet spectrum exclusively emanates from the white dwarf and shows numerous heavy element absorption lines. We measured accurate radial velocities of the red dwarf component motion, traced by both optical absorption and emission lines, and new radial velocities of the white dwarf, traced by ultraviolet Fe V lines. Combining these measurements, we refined the orbital parameters presented by Vennes et al. (1991), and we confirmed that the white dwarf gravitational redshift is exceptionally small with 9 +/- 2 km/s. From this we deduced that the interior is either pure helium or carbon with a thick hydrogen layer, and we derived, for the combined interior compositions, a white dwarf mass and radius of MWD = 0.44-050 solar mass and RWD = 0.028-0.036 solar radius. We suggest that Feige 24 could be a typical case of close binary evolution leading to the formation of a low-mass helium white dwarf. The mass of the red dwarf and the inclination of the system naturally follow: MdM = 0.26-0.33 solar mass, i greater than or equal to 75 deg. High-dispersion H-alpha line profiles are asymmetrical, strongly enhanced toward the blue, suggesting a moving atmosphere possibly linked to a mass loss rate of 10-10 solar mass/yr. The IUE spectra taken when the system is near inferior conjunction show strong He II 1640 A absorption. The profile is highly variable in width and intensity. Because it is correlated with the passage of the white dwarf at inferior conjunction, the absorption may occur in some foreground plasma emanated by the red dwarf and accumulating near a Lagrangian point or, alternatively, it may originate in an accretion spot on the white dwarf surface coaligned with the major orbital axis. Either way, the He II detection may imply substantial mass loss from the red dwarf with a corollary reclassification of Feige 24 as a mixed He/H DAO white dwarf resulting from accretion of secondary mass-loss material. Feige 24 is the prototype of a class of young, EUV-emitting, binary systems comprising a late main sequence secondary and a hot H-rich white dwarf; the class is characterized by optical and ultraviolet photospheric He II absorption, circumstellar C IV lambda (1550) absorption, and by the presence of EUV-induced, phase-dependent Balmer fluorescence. These young systems present the best opportunity to constrain theory of common-envelope evolution. Publication: The Astronomical Journal Pub Date: November 1994 DOI: 10.1086/117201 Bibcode: 1994AJ....108.1881V Keywords: Absorption Spectra; Binary Stars; Dwarf Stars; Helium; Light (Visible Radiation); Red Dwarf Stars; Stellar Mass Accretion; Stellar Spectra; Ultraviolet Astronomy; Ultraviolet Spectra; Visible Spectrum; Astronomical Spectroscopy; Balmer Series; Emission Spectra; H Alpha Line; Iue; Radial Velocity; Stellar Envelopes; Stellar Mass; Velocity Measurement; Astronomy; STARS: INDIVIDUAL: FEIGE 24; BINARIES: SPECTROSCOPIC full text sources ADS | data products SIMBAD (11) MAST (2) INES (1)