The orbit of GK Persei

Crampton, D.; Cowley, A. P.; Fisher, W. A.

doi:10.1086/163856

Cited by 64 publications

(68 citation statements)

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“…These values are in accordance with the masses obtained by Crampton et al (1986), M/M ≈ 0.9 ± 0.2 and M sec /M ≈ 0.25. A similar WD mass estimate was obtained by Reinsch (1994), M/M ≥ 0.78.…”

Section: Gk Persupporting

confidence: 92%

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GK Persei and EX Hydrae: Intermediate polars with small magnetospheres

Suleimanov

Doroshenko

Ducci

et al. 2016

A&A

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Observed hard X-ray spectra of intermediate polars are determined mainly by the accretion flow velocity at the white dwarf surface, which is normally close to the free-fall velocity. This allows us to estimate the white dwarf masses as the white dwarf mass-radius relation M − R and the expected free-fall velocities at the surface are well known. This method is widely used. However, derived white dwarf masses M can be systematically underestimated because the accretion flow is stopped at, and re-accelerates from, the magnetospheric boundary R m and, therefore, its velocity at the surface is lower than free fall. To avoid this problem, we computed a two-parameter set of model hard X-ray spectra, which allows us to constrain a degenerate M − R m dependence. Previous works showed that power spectra of accreting X-ray pulsars and intermediate polars exhibit breaks at frequencies corresponding to Keplerian frequencies at the magnetospheric boundary. Therefore, the break frequency ν b in an intermediate polar power spectrum gives another relation in the M − R m plane. The intersection of the two dependences allows us, therefore, to determine the white dwarf mass and magnetospheric radius simultaneously. To verify the method, we analysed the archival Suzaku observation of EX Hya, obtaining M/M = 0.73 ± 0.06 and R m /R = 2.6 ± 0.4, which is consistent with the values determined by other authors. Subsequently, we applied the same method to a recent NuSTAR observation of another intermediate polar GK Per performed during an outburst and found M/M = 0.86 ± 0.02 and R m /R = 2.8 ± 0.2. The long duration observations of GK Per in quiescence performed by Swift/BAT and INTEGRAL observatories indicate increase of magnetosphere radius R m at lower accretion rates.

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Section: Gk Persupporting

confidence: 92%

“…The intermediate polar GK Per (Watson et al 1985) has a very long orbital period (P orb ≈ 1.99 days) and a K1 subgiant secondary star (Warner 1976;Crampton et al 1986;Morales-Rueda et al 2002). GK Per is also classified as a dwarf nova with very long outbursts (≈50 days) repeated roughly every three years (Šimon 2002).…”

Section: Gk Permentioning

confidence: 99%

GK Persei and EX Hydrae: Intermediate polars with small magnetospheres

Suleimanov

Doroshenko

Ducci

et al. 2016

A&A

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“…The accretion-corrected mass of 1.15 ± 0.15 M for GK Per is within the error bars of the values from other methods: 0.9 ± 0.2 M from Crampton et al (1986) Aizu (1973) provides a direct conversion from the bremsstrahlung temperature to mass of the white dwarf. which we use to derive the masses as listed in Table 5.…”

Section: Discussion Of Individual Objectssupporting

confidence: 75%

Intermediate polars in the Swift/BAT survey: spectra and white dwarf masses

Brunschweiger

Greiner

Ajello

et al. 2009

A&A

100

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Context. White dwarf masses in cataclysmic variables are difficult to determine accurately, but are fundamental for understanding binary system parameters, as well as binary evolution. Aims. We investigate the X-ray spectral properties of a sample of Intermediate Polars (IP) detected above 15 keV to derive the masses of their accreting white dwarfs. Methods. We use data from the Swift/BAT instrument which during the first 2.5 yrs of operation has detected 22 known intermediate polars. The X-ray spectra of these sources are used to estimate the mass of the white dwarfs. Results. We are able to produce a mass estimate for 22 out of 29 of the confirmed intermediate polars.Comparison with previous mass measurements shows good agreement. For GK Per, we were able to detect spectral changes due to the changes in the accretion rate. Conclusions. The Swift/BAT detector with its combination of sensitivity and all-sky coverage provides an ideal tool to determine accurate white dwarf masses in intermediate polars. This method should be applied to other magnetic white dwarf binaries.

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“…The orbital period is quite long -1.997 d [7] and the distance to the object is well defined -470 pc [8]. The secondary is a K2 type subgiant with the mass of 0.25 M ⊙ ( [9], [6]) and the mass of the primary is ≤0.72 M ⊙ [6].…”

Section: Introductionmentioning

confidence: 99%

Multimission observations of the old nova GK Per during the 2015 outburst

Zemko

Orio

Luna

et al. 2017

Monthly Notices of the Royal Astronomical Society

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The remarkable old nova and an intermediate polar (IP) -GK Per was observed with Swift, the Chandra HETG and NuSTAR during its recent dwarf nova (DN) outburst in March -April 2015. Monitoring the outburst, we noticed several processes occurring on different time scales, such as: the slow evolution of the very soft X-ray emission (below 0.6 keV) during the first two weeks of the outburst and the very fast saturation of the X-ray flux above 1 keV. The Swift UVOT lights curves also showed different behaviour, depending on the filter. The broad band X-ray spectra revealed the presence of at least three different emitting sources. The white dwarf (WD) spin was observed even in the very hard X-ray range of NuSTAR, indicating that the modulation is not due to absorption, in contrast to a typical IP. It is also supported by the similarity of the on-pulse and off-pulse X-ray spectra. We propose that the scenario when the inner accretion disk pushed towards the WD by the increased accretion obscures the lower WD pole can work also for GK Per. The Golden Age

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The orbit of GK Persei

Cited by 64 publications

References 0 publications

GK Persei and EX Hydrae: Intermediate polars with small magnetospheres

GK Persei and EX Hydrae: Intermediate polars with small magnetospheres

Intermediate polars in the Swift/BAT survey: spectra and white dwarf masses

Multimission observations of the old nova GK Per during the 2015 outburst

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