Simultaneous Photometry and Spectroscopy of the Supersoft X-Ray Source RX J0019.8+2156 (QR Andromedae)

McGrath, T. K.; Schmidtke, P. C.; Cowley, A. P.; Ponder, A. L.; Wagner, R. M.

doi:10.1086/322109

Cited by 9 publications

(10 citation statements)

References 11 publications

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“…In order to estimate the inclination of the system, we will compare the light curve of WX Cen with that of QR And. From the observed amplitude of the light curve of QR And, which varies from Δ m = 0.25 mag (Meyer‐Hofmeister et al 1998) to Δ m = 0.5 mag (McGrath et al 2001), an inclination of i = 55° was derived (Meyer‐Hofmeister et al 1998). As the observed light‐curve amplitude of WX Cen is within the observed range for QR And, and as the overall light‐curve shape and photometric behaviour are similar, we will adopt i = 55° for WX Cen as well.…”

Section: Discussionmentioning

confidence: 99%

WX Cen (≡ WR 48c) – a possible Type Ia supernova progenitor

Oliveira

Steiner²

2004

Monthly Notices of the Royal Astronomical Society

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We confirm the orbital period of WX Cen ≡ WR 48c determined by Diaz & Steiner and refined its value to P orb = 0.416 961 5(±22) d. The light curve of this object has a peak-topeak variation of approximately 0.32 mag. It is non-sinusoidal in the sense that it has a V-shaped narrow minimum, similar to the ones seen in V Sge, V617 Sgr and in compact binary supersoft sources (CBSS).Most of the emission lines in the optical spectrum are due to Balmer, He II, C IV, N V, O V and O VI. An analysis of the He II Pickering series decrement shows that the system has significant amount of hydrogen. The emission lines of He II 4686 Å became weaker between the 1991 and 2000/2002 observations, indicating distinct levels of activity. The spectra of WX Cen show variable absorption features in the Balmer lines with V = −2900 km s −1 and in emission with V = ±3500 km s −1 . These highly variable features remind us of the satellite emission lines found in the spectra of CBSS.We estimate the colour excess as E(B − V ) = 0.63 on the basis of the observed diffuse interstellar band at 5780 Å. Given the distance-colour excess relation in the direction of WX Cen, this implies a distance of 2.8 ± 0.3 kpc. Interstellar absorption of the Na I D lines show components at −4.1 km s −1 , which corresponds to the velocity of the Coalsack, and three other components at −23.9, −32.0 and −39.0 km s −1 . These components are also seen with similar strengths in field stars that have distances between 1.8 and 2.7 kpc. The intrinsic colour of WX Cen is (B − V ) 0 = −0.2 and the absolute magnitude is M V = −0.5.Extended red wings in the strong emission lines are seen. A possible explanation is that the system has a spill-over stream similar to what is seen in V617 Sgr. We predict that when observed in opposite phase, blue wings would be observed. A puzzling feature that remains to be explained is the highly variable red wing (V ∼ 700 km s −1 ) of the O VI emission lines as well as of the red wings of the H and He lines.The velocity of the satellite-like feature is consistent with the idea that the central star is a white dwarf with a mass of M ∼ 0.9 M . With the high accretion rate under consideration, the star may become a Type Ia supernova (SN Ia) in a time-scale of 5 × 10 6 yr.

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Section: Discussionmentioning

confidence: 99%

WX Cen (≡ WR 48c) – a possible Type Ia supernova progenitor

Oliveira

Steiner²

2004

Monthly Notices of the Royal Astronomical Society

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“…Another possibility for the SSXBs with q < 1 can be an induced wind of the donor (van Teeseling & King 1998;Knigge et al 2000). The role of the latter scenario may be more important than thought previously because QR And which had been supposed to have q > 1 was proven to have q < 1 (McGrath et al 2001).…”

Section: Absolute Magnitudes Of the Short-period Systemsmentioning

confidence: 95%

Luminous binary supersoft X-ray sources: Optical colors and absolute magnitudes

Šimon

2003

A&A

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Abstract. An analysis of the color indices and absolute magnitudes M V0 of the "classical" supersoft X-ray binary sources (SSXBs), the V Sge-type stars (VSs), the symbiotic SSXBs, and the classical novae in the soft X-ray phase is presented. This approach can help comparing the properties and configuration of the reprocessing medium in the individual systems. The range of M V0 of the individual objects is very large, from M V0 = 8.5 to M V0 = −4, most systems having M V0 < 2. The objects with the orbital period P orb < 4 days tend to possess brighter M V0 with the increasing P orb . The same trend is apparent also for M U0 . There is no systematic difference between the classical SSXBs and the VSs, as regards their M V0 and M U0 . The soft X-ray phase of the novae V 1974 Cyg and V 382 Vel occurred at significantly brighter M V0 than those of most other SSXBs while M V0 of the recurrent nova U Sco was comparable to the SSXBs of the comparable P orb . We showed that the luminosity of the reprocessing medium in the symbiotic SSXBs does not increase much with P orb , when compared with the luminosity of the classical SSXBs and VSs; this speaks against large disks in these symbiotics. The classical SSXBs and the VSs have colors very similar each to other and form closed groups in the color-color diagrams. A Balmer jump occurs frequently in emission as inferred from the colors. The correlation between the bolometric luminosity, determined from the X-ray spectra and M V0 or M U0 of all kinds of the SSXBs is rather weak, but resolvable, and is more prominent for M U0 . The implications for the reprocessing medium are discussed.

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“…Recent observations revealed a low radial velocity component to the He II λ4686 emission line (e.g. Becker et al 1998;Cowley et al 1998;Deufel et al 1999;McGrath et al 2001). These authors considered that the He II λ4686 emission line was emitted from the white dwarf or from the inner part of the accretion disc.…”

Section: Supersoft X-ray Sourcesmentioning

confidence: 99%

Numerical simulation of the surface flow on the companion star in a close binary system

Oka

Matsuda

Hachisu³

et al. 2004

A&A

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Abstract. We perform three-dimensional numerical simulations of surface flows on the companion star in a semi-detached binary system and construct the corresponding Doppler maps. The mass ratio of the binary system, q = M 2 /M 1 , considered here is q = 0.05, 0.33, 0.5, 1, 2, and 3. For all cases, we obtain the H-, L1-, and L2-eddies, as found in our previous work, and confirm that the flow pattern does not heavily depend on the mass ratio. We propose that this kind of problem be dubbed "stellar meteorology". The Doppler maps at the position of the companion show a structure tilted towards clockwise direction and presenting deviations from the critical Roche surface due to the L1-eddy and the L2-eddy on the companion star. We apply our results to the Galactic supersoft X-ray source RX J0019.8+2156 and try to attribute the low radial velocity component of the emission lines of He II λ4686 observed recently to the irradiated spot on the surface of the companion rather than that of the white dwarf or the accretion disc. Based on the comparison between the observations and our constructed Doppler map, we estimate the mass of the companion star in RX J0019.8+2156 to be ∼2 M assuming the mass of the white dwarf star to be around 0.6 M .

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Simultaneous Photometry and Spectroscopy of the Supersoft X-Ray Source RX J0019.8+2156 (QR Andromedae)

Cited by 9 publications

References 11 publications

WX Cen (≡ WR 48c) – a possible Type Ia supernova progenitor

WX Cen (≡ WR 48c) – a possible Type Ia supernova progenitor

Luminous binary supersoft X-ray sources: Optical colors and absolute magnitudes

Numerical simulation of the surface flow on the companion star in a close binary system

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