The new eclipsing magnetic binary system E 1114 + 182

Biermann, Peter L.; Schmidt, Gary D.; Liebert, James; Tapia, S.; Strittmatter, P. A.; West, S.; Stockman, H. S.; Kuehr, H.; Lamb, D. Q.

doi:10.1086/163238

Cited by 33 publications

(30 citation statements)

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“…There are further X-ray observations reported by Biermann et al (1985), and Schaaf et al (1987), respectively, with the EINSTEIN and EXOSAT satellites. We make use of the timing of the X-ray eclipses detected with Einstein, the EXOSAT data have a too low count-rate and are not used further in this paper.…”

Section: Rosat Pspcmentioning

confidence: 68%

A multiwavelength timing analysis of the eclipsing polar DP Leo

Schwope

Hambaryan

Schwarz

et al. 2002

A&A

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Abstract.We present an analysis of the X-ray light curves of the magnetic cataclysmic variable DP Leo using recently performed XMM−Newton EPIC and archival published and unpublished ROSAT PSPC observations. We combine the timings of the X-ray eclipses with timings derived from archival HST-observations and new optical observations with the photon counting OPTIMA camera. We determine the eclipse length at X-ray wavelengths to be 235 ± 5 s, slightly longer than at ultra-violet wavelengths, where it lasts 225 s. A new orbital ephemeris is derived which connects the more than 120 000 binary cycles covered since 1979. It has a highly significant quadratic term, implying an orbital period change ofṖ = −4.4 × 10 −12 s s −1 , two orders of magnitude larger than being compatible with braking by gravitational radiation only. Over the last twenty years, the optical and X-ray bright phases display a continuous shift with respect to the eclipse center by ∼2.1• yr −1 . Over the last 8.5 years the shift of the X-ray bright phase is ∼2.5• yr −1 . We interpret this as evidence of an asynchronously rotating white dwarf although synchronization oscillations cannot be ruled out completely. If the observed phase shift continues, a fundamental rearrangement of the accretion geometry must occur on a time-scale of some ten years. Applying model atmosphere spectra to optical/UV eclipse light curves, we determine the temperature and mass of the white dwarf, the temperature and size of the optical/UV emitting spot and the distance to DP Leo to be T wd = 13 500 K, M wd 0.6 M , T spot = 32 000 K, A spot 0.1 A wd , and D = 400 pc, respectively. The implied inclination and mass ratio are i = 79.5• and Q = M wd /M 2 = 6.7. DP Leo is marginally detected at eclipse phase in X-rays. The upper limit eclipse flux is consistent with an origin on the late-type secondary, L X 2.5 × 10 29 ergs s −1 (0.20−7.55 keV), at a distance of 400 pc.

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Section: Rosat Pspcmentioning

confidence: 68%

A multiwavelength timing analysis of the eclipsing polar DP Leo

Schwope

Hambaryan

Schwarz

et al. 2002

A&A

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“…Combining these with reanalyzed previous data, the authors find that a single circumbinary companion gives the best explanation for the O−C curve. DP Leo was the first eclipsing polar discovered (Biermann et al 1985). A decrease in the binary period was noticed by Schwope et al (2002) and Pandel et al (2002).…”

Section: A2 Eclipsing Wd+ms Pcebsmentioning

confidence: 93%

Origin of apparent period variations in eclipsing post-common-envelope binaries

Zorotovic

Schreiber

2013

A&A

119

163

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Context. Apparent period variations detected in several eclipsing, close-compact binaries are frequently interpreted as being caused by circumbinary giant planets. This interpretation raises the question of the origin of the potential planets that must have either formed in the primordial circumbinary disk, together with the host binary star, and survived its evolution into a close-compact binary or formed in a post-common-envelope circumbinary disk that remained bound to the post-common-envelope binary (PCEB). Aims. Here we combine current knowledge of planet formation and the statistics of giant planets around primordial and evolved binary stars with the theory of close-compact binary star evolution aiming to derive new constraints on possible formation scenarios. Methods. We compiled a comprehensive list of observed eclipsing PCEBs, estimated the fraction of systems showing apparent period variations, reconstructed the evolutionary history of the PCEBs, and performed binary population models of PCEBs to characterize their main sequence binary progenitors. We reviewed the currently available constraints on the fraction of PCEB progenitors that host circumbinary giant planets. Results. We find that the progenitors of PCEBs are very unlikely to be frequent hosts of giant planets ( < ∼ 10 per cent), while the frequency of PCEBs with observed apparent period variations is very high (∼90 per cent). Conclusions. The variations in eclipse timings measured in eclipsing PCEBs are probably not caused by first-generation planets that survived common-envelope evolution. The remaining options for explaining the observed period variations are second-generation planet formation or perhaps variations in the shape of a magnetically active secondary star. We suggest observational tests for both options.

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“…These are listed in Table 8 with the relevant numbers and references. In all cases the narrow component (2) -0.08 (5) ~ 0.00 (6) 0.01 (2) -0.02 (2) Biermann et al 1985Mukai & Charles 1987, Bailey et al 1985Mukai S¿ Charles 1987Young & Schneider 1979Young, Schneider, & Schectman 1981Beuermann et al 1988, Allen et al 1989Silber et al 1992Martell, Horne, Gomer, & Price 1994 This paper Beuermann & Thomas 1990Ilessman 1986Dhillon, Jones, & Marsh 1994Hessman 1989 Notes to Table 8 Note 1. To be eligible for this list, a star must show another clue to the secondary's location, of greater reliability and precision.…”

Section: Location Of the Secondary Starmentioning

confidence: 93%

The Remarkable Eclipsing Asynchronous AM Herculis Binary RX J19402-1025

Patterson

Skillman²,

Thorstensen

et al. 1995

PASP

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We report on two years of photometric and spectroscopic observation of the recently discovered AM Herculis star RX J19402-1025. A sharp eclipse feature is present in the optical and X-ray light curves, repeating with a period of 12116.290±0.003 s. The out-of-eclipse optical waveform contains approximately equal contributions from a signal at the same period and another signal at 12150 s. As these signals drift in and out of phase, the wave form of the light curve changes in a complex but predictable manner. After one entire "supercycle" of 50 days (the beat period between the shorter periods), the light curve returns to its initial shape. We present long-term ephemerides for each of these periods. It is highly probable that the eclipse period is the underlying orbital period, while the magnetic white dwarf rotates with P = 12150 s. The eclipses appear to be eclipses of the white dwarf by the secondary star. But there is probably also a small obscuring effect from cold gas surrounding the secondary, especially on the orbit-leading side where the stream begins to fall towards the white dwarf. The latter hypothesis can account for several puzzling effects in this star, as well as the tendency among most AM Her stars for the sharp emission-line components to slightly precede the actual motion of the secondary. The presence of eclipses in an asynchronous AM Her star provides a marvelous opportunity to study how changes in the orientation of magnetic field lines affect the accretion flows. Repeated polarimetric light curves and high-resolution studies of the emission lines are now critical to exploit this potential. Leighly et al. 1993). Among active galactic nuclei, this was the only strictly periodic signal reported at any wavelength that passes tests of persistence and phase stability. It has been difficult to understand this behavior. Madejski et al. (1993) have ended the mystery by showing that, although the period is indeed real, it belongs not to NGC 6814 but to another X-ray source 37 arcmin away in the sky. Follow-up spectroscopy and photometry of several stars in the smaller X-ray error circle revealed the nature of the interloper: a cataclysmic variable, almost certainly of the AM Herculis variety, and provisionally named RX J19402 -1025 (Madejski et al. 1993;Staubert et al. 1994; «2000= 19 h 40 m ll?6, <%ooo= -10°25'25'. '7).Although NGC 6814 is now relegated to obscurity, the new X-ray source will surely become one of the most-307

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The new eclipsing magnetic binary system E 1114 + 182

Cited by 33 publications

References 0 publications

A multiwavelength timing analysis of the eclipsing polar DP Leo

A multiwavelength timing analysis of the eclipsing polar DP Leo

Origin of apparent period variations in eclipsing post-common-envelope binaries

The Remarkable Eclipsing Asynchronous AM Herculis Binary RX J19402-1025

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