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1.
A spectroscopic study of the frequently outbursting dwarf nova UY Pup has been undertaken whilst the system was in outburst. The Hα andHβ line profiles in UY Pup are typical of low inclination dwarf novae after outburst maximum. No evidence for two components is seen in the emission lines. Using radial velocity measurements of Hα, we find the best fit orbital period for the system to be 10.22 ± 0.19 h(although we cannot with certainty rule out a period of 7.13 ± 0.14 h).We place limits on the system parameters. We also present multicolour photometry of UY Pup in quiescence. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

2.
We present time-resolved optical spectroscopy and photometry of the nova-like cataclysmic variable V348 Puppis. The system displays the same spectroscopic behaviour as SW Sex stars, so we classify V348 Pup as a new member of the class. V348 Pup is the second SW Sex system (the first is V795 Herculis) which lies in the period gap. The spectra exhibit enhanced He  ii λ 4686 emission, reminiscent of magnetic cataclysmic variables. The study of this emission line gives a primary velocity semi-amplitude of     . We have also derived the system parameters, obtaining:     ,         ,     and     . The spectroscopic behaviour of V348 Pup is very similar to that of V795 Her, with the exception that V348 Pup shows deep eclipses. We have computed the '0.5-absorption' spectrum of both systems, obtaining spectra that resemble the absorption spectrum of a B0 V star. We propose that absorption in SW Sex systems can be produced by a vertically extended atmosphere which forms where the gas stream re-impacts the system, either at the accretion disc or at the magnetosphere of the white dwarf (assuming a magnetic scenario).  相似文献   

3.
The eclipsing nova-like cataclysmic variable star V348 Pup exhibits a persistent luminosity modulation with a period 6 per cent longer than its 2.44-h orbital period ( P orb). This has been interpreted as a 'positive superhump' resulting from a slowly precessing non-axisymmetric accretion disc gravitationally interacting with the secondary. We find a clear modulation of mid-eclipse times on the superhump period, which agrees well with the predictions of a simple precessing eccentric disc model. Our modelling shows that the disc light centre is on the far side of the disc from the donor star when the superhump reaches maximum light. This phasing suggests a link between superhumps in V348 Pup and late superhumps in SU UMa systems. Modelling of the full light curve and maximum entropy eclipse mapping both show that the disc emission is concentrated closer to the white dwarf at superhump maximum than at superhump minimum. We detect additional signals consistent with the beat periods between the implied disc precession period and both and  相似文献   

4.
We present time-resolved spectroscopy and photometry of the double-lined eclipsing cataclysmic variable V347 Pup (=LB 1800). There is evidence of irradiation on the inner hemisphere of the secondary star, which we correct for using a model to give a secondary-star radial velocity of   K R= 198 ± 5 km s−1  . The rotational velocity of the secondary star in V347 Pup is found to be   v sin  i = 131 ± 5 km s−1  and the system inclination is   i = 840 ± 23  . From these parameters we obtain masses of   M 1= 0.63 ± 0.04 M⊙  for the white dwarf primary and   M 2= 0.52 ± 0.06 M⊙  for the M0.5V secondary star, giving a mass ratio of   q = 0.83 ± 0.05  . On the basis of the component masses, and the spectral type and radius of the secondary star in V347 Pup, we find tentative evidence for an evolved companion. V347 Pup shows many of the characteristics of the SW Sex stars, exhibiting single-peaked emission lines, high-velocity S-wave components and phase-offsets in the radial velocity curve. We find spiral arms in the accretion disc of V347 Pup and measure the disc radius to be close to the maximum allowed in a pressureless disc.  相似文献   

5.
V347 Pup is the first novalike system with clear spiral arms in its accretion disc, as evidenced from its HeI Doppler maps. Combining the Doppler maps of the various lines of the system V347 Pup a more complex structure is revealed on the first arm. On the Doppler maps of HeI λ5875 emission line the first arm splits to two smaller and thinner structures. The Doppler map of HeI λ6678 emission line shows that this line dominates the region of thin structure with higher velocities that we met on the Doppler map of HeI λ5875 emission line. On the contrary the Hα emission line dominates the region of thin structure with lower velocities. We therefore observe, that the Hα emission line dominates on the exterior of the first arm, and the emission line of HeI on the interior. Most of NaI is probably emanated from the white dwarf or from the interior of the disc, and then being absorbed by the spiral shocks.  相似文献   

6.
Data from spectrophotometric observations in the 485-1105 nm range at different times are used to determine the basic physical parameters of the continuum radiating layer of L2 Pup: spectrophotometric temperatures, radii, and velocities of recession from the star's center. The phase dependences of these parameters over a cycle, during which the temperature varied from 2300 to 2900 K and the variations in radius were as high as 60%, are determined. The radius of the radiating layer is seen to vary irregularly, the radius of the layer is found to depend on wavelength, and the variations in the expansion velocity are evaluated. Translated from Astrofizika, Vol. 52, No. 1, pp. 99–115 (February 2009).  相似文献   

7.
We present time-resolved optical spectroscopy of the deeply eclipsing nova-like binary V347 Pup, which provides evidence for a rotational velocity field in the low-excitation lines, as expected from accretion disc emission. The low-excitation line profiles are a composite of the disc and the irradiated inner-face of the donor star. This picture is remarkably simple compared to the other members of the eclipsing nova-like family. Unsatisfactory radial velocity solutions for the accreting object provided by standard methods encourage us to apply a technique developed to measure stellar motion from tomographic reconstructions of the time-dependent line profiles. We find some evidence for a spiral pattern over the disc and for disc-overflow accretion. If the emission distribution proves to be a long-term feature, V347 Pup will provide an opportunity to study disc kinematics with greater confidence than allowed by the other eclipsing nova-like objects.  相似文献   

8.
The nearby Mira-like variable L2 Pup is shown to be undergoing an unprecedented dimming episode. The stability of the period rules out intrinsic changes to the star, leaving dust formation along the line of sight as the most likely explanation. Episodic dust obscuration events are fairly common in carbon stars but have not been seen in oxygen-rich stars. We also present a 10-μm spectrum, taken with the Japanese Infrared Telescope in Space satellite, showing strong silicate emission that can be fitted with a detached, thin dust shell, containing silicates and corundum.  相似文献   

9.
We use the method introduced by Karami & Mohebi (2007), and Karami & Teimoorinia (2007) which enable us to derive the orbital parameters of the spectroscopic binary stars by the nonlinear least squares of observed vs. curve fitting (o-c). Using the measured experimental data for radial velocities of the four double-lined spectroscopic binary systems PV Pup, HD 141929, EE Cet and V921 Her, we find both the orbital and the combined spectroscopic elements of these systems. Our numerical results are in good agreement with those obtained using the method of Lehmann-Filhés.  相似文献   

10.
In this paper we present theBV photoelectric light curves of the W UMa-type eclipsing binary TY Pup. We have gained ephemerides by means of the times of minima. The obtained light curves have been solved using Wilson-Devinney's synthetic code. The results indicate that TY Pup is a contact system with mass ratio 0.185 and a large degree of overcontact of 52%. Combined with spectroscopic material, absolute parameters of TY Pup are derived. It may be concluded that TY Pup is an evolved contact binary.  相似文献   

11.
We present the second part of the results of our work to investigate the atmospheric parameters and chemical composition of southern-hemisphere Cepheids obtained by analyzing 24 spectra for eight bright Cepheids and three semiregular bright supergiants taken with the 1.9-m telescope of the South African Astronomical Observatory. The chemical composition and atmospheric parameters have been determined for S Cru, AP Pup, AX Cir, S TrA, T Cru, R Mus, S Mus, U Car, V382 Car, HD 75276, and R Pup.  相似文献   

12.
Deep optical imaging of nova remnants: a southern sky sample   总被引：1，自引：0，他引：1  
We present an optical imaging study of 20 southern sky nova remnants which has resulted in the discovery of four previously unknown nova shells — those of V842 Cen, RR Cha, DY Pup and HS Pup. The study has also revealed previously unobserved features in three other known shells — those of BT Mon, CP Pup and RR Pic. The images of BT Mon, V842 Cen, RR Cha, DY Pup and HS Pup have been processed using several deconvolution algorithms (Richardson–Lucy, maximum entropy and CLEAN ) in addition to straightforward point-source subtraction in an attempt to resolve the shells from the central stars. The use of four different methods enables us to make a qualitative judgment of the results. Notably, the shell of RR Pic displays tails extending outwards from clumps in the main ejecta similar to those previously detected in DQ Her.  相似文献   

13.
M.R. Sanad 《New Astronomy》2010,15(5):409-416
The main aim of this study is to use archival low-dispersion spectra from the International Ultraviolet Explorer (IUE) in an attempt to follow up the spectral behavior of two symbiotic Mira systems RR Tel and RX Pup of the period from 1978–1995 and 1979–1989 for two systems respectively. We concentrated on studying N IV 1486 Å intercombination line, coming from the emission nebulae (Bryan and Kwok, 1991, Muerset et al., 1991, Murset and Nussbaumer, 1994), by calculating the line fluxes and line widths of N IV 1486 Å. We found that there is a disparity of spectral variability for these physical parameters at different times for both systems. For RR Tel, both line fluxes and line widths are increasing with the phase, while for RX Pup, both line fluxes and line widths are decreasing with the phase. There is a relation between the parameters of this emission line (line flux, line width) and phase, which we attribute to the variations of temperature of the emission nebulae at different times, as a result of the activity of the hot component.  相似文献   

14.
We present results obtained from near-infrared JHK spectroscopic observations of novae V2491 Cygni and V597 Puppis in the early declining phases of their 2007 and 2008 outbursts, respectively. In both objects, the spectra displayed emission lines of H  i , O  i , He  i and N  i . In V597 Pup, the He  i lines were found to strengthen rapidly with time. Based on the observed spectral characteristics, both objects are classified as He/N novae. We have investigated the possibility of V2491 Cyg being a recurrent nova as has been suggested. By studying the temporal evolution of the linewidths in V2491 Cyg, it appears unlikely that the binary companion is a giant star with heavy wind as in recurrent novae of the RS Oph type. Significant deviations from that of recombination case B conditions are observed in the strengths of the H  i lines. This indicates that the H  i lines, in both novae, are optically thick during the span of our observations. The slope of the continuum spectra in both cases was found to have a  λ−(3−3.5)  dependence which deviates from a Rayleigh–Jeans spectral distribution. Both novae were detected in the post-outburst supersoft X-ray phase; V2491 Cyg being very bright in X-rays has been the target of several observations. We discuss and correlate our infrared observations with the observed X-ray properties of these novae.  相似文献   

15.
Orbital period changes of ten contact binary systems (S Ant, ε CrA, EF Dra, UZ Leo, XZ Leo, TY Men, V566 Oph, TY Pup, RZ Tau and AG Vir) are studied based on the analysis of their     curves. It is discovered that the periods of the six systems, S Ant, ε CrA, EF Dra, XZ Leo, TY Men and TY Pup, show secular increases. For UZ Leo, its secular period increase rate is revised. For the three systems, V566 Oph, RZ Tau and AG Vir, weak evidence is presented that a periodic oscillation (with periods of 20.4, 28.5 and 40.9 yr respectively) is superimposed on a secular period increase. The cyclic period changes can be explained by the presence of an unseen third body in the three systems. All the sample stars studied are contact binaries with     .
Furthermore, orbital period changes of 27 hot contact binaries have been checked. It is found that, apart from AW UMa with the lowest mass ratio     , none shows an orbital period decrease. The relatively weak magnetic activity in the hotter contact binaries means little angular momentum loss (AML) from the systems via magnetic stellar winds. The period increases of these W UMa binaries can be explained by mass transfer from the secondary to the primary components, which is in agreement with the prediction of the thermal relaxation oscillation (TRO) models. This suggests that the evolution of a hotter W UMa star is mainly controlled by TRO. On the other hand, for a cooler W UMa star     , its evolution may be TRO plus AML, which coincides with the recent results of Qian.  相似文献   

16.
We describe X-ray and optical observations of the symbiotic star RX Pup. From low resolution optical spectra, we obtain a reddening for RX Pup of E(B−V)=0.79. We use the neutral column density corresponding to this reddening as a lower limit for the X-ray spectra fits. The X-ray spectra can be fitted with either a two-temperarure thermal plasma model or a single-temperature plasma plus a narrow line at ≈0.55 keV, each modified by interstellar absorption. The RX Pup X-ray flux is not variable within the observation exposure time, suggesting that unlike in most CVs, an accretion disk boundary layer does not contribute significantly to the X-ray flux. Instead, the X-ray emission may come from shock-heated gas further away from the compact object.  相似文献   

17.
The population of the rotational levels of vibrational and electronic ground state of interstellar H2 has been calculated; different possible excitation and de-excitation mechamisms including the ultraviolet pumping and formation and destruction of molecules have been considered. The values of temperature, density and radiation field towards ζ Oph, ? Per and ζ Pup have been obtained by comparing the theoretical distributions with the observations. The results indicate the presence of a high temperature low density diffuse cloud towards ζ Pup and low temperature high density clouds towards ζ Oph and ? Per. The results of this work were presented at the February, 1974 meeting of the Astronomical Society of India (Joshi and Tarafdar, 1974).  相似文献   

18.
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19.
We present the results of our monitoring of the semiregular variable HU Pup in the 1612, 1665, and 1667-MHz OH lines and the 22.235-GHz H2O line. The maser emission in the 1612-MHz satellite line has been detected from this source for the first time. Strong variability of the emission has been observed in all three OH lines, including the radial-velocity drift of the two most intense features. Zeeman splitting components have been found. The longitudinal magnetic field strength has been estimated to be 1.0, 1.6 and 2.7, 3.2 mG in the 1665 and 1667-MHz lines, respectively. Our OH and H2O observations have revealed fairly stable structures in the masing region and have allowed us to estimate the variability period of the maser emission (～1.5 yr). A possible model of the maser source in HU Pup is discussed.  相似文献   

20.
The contribution of bound-free and free-free processes to the outward acceleration of Pup is studied and is found to be negligible.  相似文献   

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