Determination of the basic parameters of the dwarf nova EY Cygni

Echevarría, J.; Michel, R.; Costero, R.; Zharikov, S. V.

doi:10.1051/0004-6361:20052906

Cited by 20 publications

(26 citation statements)

References 35 publications

(68 reference statements)

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“…A convenient tool for the analysis of the masses and inclination angle of the binary has been developed by Echevarría et al (2007). This M 1 – M 2 diagnostic diagram is shown in Fig.…”

Section: The M1–m2 Diagrammentioning

confidence: 99%

High-dispersion absorption-line spectroscopy of AE Aqr

Echevarría

Smith

Costero

et al. 2008

Monthly Notices of the Royal Astronomical Society

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High‐dispersion time‐resolved spectroscopy of the unique magnetic cataclysmic variable AE Aqr is presented. A radial velocity analysis of the absorption lines yields K2= 168.7 ± 1 km s−1. Substantial deviations of the radial velocity curve from a sinusoid are interpreted in terms of intensity variations over the secondary star's surface. A complex rotational velocity curve as a function of orbital phase is detected which has a modulation frequency of twice the orbital frequency, leading to an estimate of the binary inclination angle that is close to 70°. The minimum and maximum rotational velocities are used to indirectly derive a mass ratio of q= 0.6 and a radial velocity semi‐amplitude of the white dwarf of K1= 101 ± 3 km s−1. We present an atmospheric temperature indicator, based on the absorption‐line ratio of Fe i and Cr i lines, whose variation indicates that the secondary star varies from K0 to K4 as a function of orbital phase. The ephemeris of the system has been revised, using more than 1000 radial velocity measurements, published over nearly five decades. From the derived radial velocity semi‐amplitudes and the estimated inclination angle, we calculate that the masses of the stars are M1= 0.63 ± 0.05 M⊙; M2= 0.37 ± 0.04 M⊙, and their separation is a= 2.33 ± 0.02 R⊙. Our analysis indicates the presence of a late‐type star whose radius is larger, by a factor of nearly 2, than the radius of a normal main‐sequence star of the same mass. Finally, we discuss the possibility that the measured variations in the rotational velocity, temperature and spectral type of the secondary star as functions of orbital phase may, like the radial velocity variations, be attributable to regions of enhanced absorption on the star's surface.

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“…A convenient tool for the analysis of the masses and inclination angle of the binary has been developed by Echevarría et al (2007). This M 1 – M 2 diagnostic diagram is shown in Fig.…”

Section: The M1–m2 Diagrammentioning

confidence: 99%

High-dispersion absorption-line spectroscopy of AE Aqr

Echevarría

Smith

Costero

et al. 2008

Monthly Notices of the Royal Astronomical Society

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“…Early studies of EY Cyg show that it contains a white dwarf with a mass of wd = 1.26 and a secondary of sec = 0.59 ⊙ . Later, Echevarría et al (2007) using photometric analysis derived the masses as wd = 1.10 ± 0.09 ⊙ and sec = 0.49 ± 0.09 ⊙ confirming that the white dwarf in EY Cyg is massive. The results are also consistent with Costero et al (1998) and Sion et al (2004).…”

Section: Introductionmentioning

confidence: 88%

“…The folding procedure were carried out with XRONOS task EFOLD. We used the ephemerides 0 = 2449255.3260(9) + 0.4593249(1) HJD where the zero phase corresponds to the inferior conjunction of the secondary star (Echevarría et al, 2007). The EY Cyg folded mean light curve indicates a sinusoidal behavior of orbital modulation with a minima and maxima at phases 0.5 and 1.0, respectively.…”

Section: Timing Analysismentioning

confidence: 99%

X-ray properties of dwarf nova EY Cyg and the companion star using an XMM-Newton observation

Nabizadeh

Balman²

2020

Advances in Space Research

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A B S T R A C TWe present the X-ray analysis of dwarf nova EY Cyg using the 45 ks XMM-Newton observatory archival data obtained in quiescence. We find orbital modulations in X-rays. We simultaneously fitted EPIC pn, MOS1 and MOS2 data using a model for interstellar medium absorption (tbabs) and a multitemperature plasma emission model with a power-law distribution of temperatures (CEVMKL) as expected from low accretion rate quiescent dwarf novae. The XMM-Newton EPIC spectra of the source yields a maximum temperature max ∼ 14.9 +3.3 −2.2 keV with an unabsorbed X-ray flux and luminosity of (1.8-2.0) × 10 −12 ergs −1 cm −1 and (8.7-9.7) × 10 31 ergs −1 , respectively, in the energy range 0.1 to 50 keV. There is 3-4 sigma excess at energies below 0.5 keV, we model the excess using MEKAL, POWERLAW and BBODY models and favor the model MEKAL which is physical. According to previous studies, the secondary in this system is thought to be a K-type star which may radiate in the soft X-ray region. The fit with an additive MEKAL model gives a temperature of ∼ 0.1 keV with an unabsorbed X-ray flux and luminosity of (2.7-8.8) × 10 −14 ergs −1 cm −1 and (1.3-4.2) × 10 30 ergs −1 , respectively, for the companion star. Based on the results from the timing and spectral analysis, we highly suggest that the secondary of EY Cyg is a K-type star.

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“…115 extremely long period CV: EY Cyg (Echevarría et al 2007), and we are inclined to think that such irregular variability is connected to a spotted surface of the donor star. As for polarimetry, the object does not show any measurable linear polarization.…”

Section: V479 And: CV Lmxb or Symbiotic?mentioning

confidence: 92%

V479 And: CV, LMXB, or Symbiotic?

Buitrago¹,

Tovmassian²,

Echevarría³

et al. 2011

Proc. IAU

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Abstract. V479 And is a 14.26 hour, close binary system, comprised of a G8-K0 star departing from the main sequence and a compact primary star accreting matter from the donor. The object is an X-ray source, modulated with the orbital period. This, and the presence of an intense He II line, leads us to speculate that the compact object is a magnetic white dwarf. However, we do not find strong constraints on the upper mass limit of the compact object, and we may have a neutron star in a low mass X-ray binary instead of a cataclysmic variable. The orbital period is certainly too short for the donor star to be an evolved giant star, so classifying this object as a symbiotic binary may be a big stretch; however there is an evidence that the mass transfer occurs via stellar winds, rather than through the L 1 point of Roche filling secondary, a phenomenon more common for symbiotic stars.

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Determination of the basic parameters of the dwarf nova EY Cygni

Cited by 20 publications

References 35 publications

High-dispersion absorption-line spectroscopy of AE Aqr

High-dispersion absorption-line spectroscopy of AE Aqr

X-ray properties of dwarf nova EY Cyg and the companion star using an XMM-Newton observation

V479 And: CV, LMXB, or Symbiotic?

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