Rapid orbital expansion in millisecond pulsar PSR J0636+5128: evaporation winds?

ABSTRACT PSR J0636+5128 is a 2.87 ms binary millisecond pulsar (MSP) discovered by the Green Bank Northern Celestial Cap Pulsar Survey, and possesses the third shortest orbital period ( P = 1.6 h) among confirmed binary pulsars. Recent observations reported that this source is experiencing a rapid orbital expansion at a rate of $\dot{P}=(1.89\pm 0.05)\times 10^{-12}\,\rm s\, s^{-1}$. The evaporation winds of the companion induced by the spin-down luminosity of the MSP may be responsible for such a positive orbital period derivative. However, our calculations show that the winds ejecting from the vicinity of the companion or the inner Lagrangian point cannot account for the observation due to an implausible evaporation efficiency. Assuming that the evaporation winds eject from the vicinity of the MSP in the form of asymmetric disc winds or outflows, the evaporation efficiency can be constrained to be ∼0.1. Therefore, the rapid orbital expansion detected in PSR J0636+5128 provides evidence of outflows and accretion disc around the MSP.

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The binary evolution of SAX J1808.4−3658: implications of an evolved donor star

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/staa1234 ◽

2020 ◽

Vol 495 (1) ◽

pp. 796-805

Author(s):

A J Goodwin ◽

T E Woods

Keyword(s):

Mass Transfer ◽

Binary System ◽

Orbital Period ◽

Lagrangian Point ◽

Millisecond Pulsar ◽

Pulsar Radiation ◽

Evolutionary Studies ◽

Period Derivative ◽

Binary Evolution ◽

Additional Loss

ABSTRACT Observations of the accretion powered millisecond pulsar SAX J1808.4−3658 have revealed an interesting binary evolution, with the orbit of the system expanding at an accelerated rate. We use the recent finding that the accreted fuel in SAX J1808.4−3658 is hydrogen depleted to greatly refine models of the progenitor and prior evolution of the binary system. We constrain the initial mass of the companion star to 1.0–1.2 M⊙, more massive than previous evolutionary studies of this system have assumed. We also infer the system must have undergone strongly non-conservative mass transfer in order to explain the observed orbital period changes. We include mass loss due to the pulsar radiation pressure on the donor star, inducing an evaporative wind which is ejected at the inner Lagrangian point of the binary system. The resulting additional loss of angular momentum resolves the discrepancy between conservative mass transfer models and the observed orbital period derivative of this system. We also include a treatment of donor irradiation due to the accretion luminosity, and find this has a non-negligible effect on the evolution of the system.

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ANALYZING THE BINARY PULSARS ABOVE THE SPIN-UP LINE

International Journal of Modern Physics Conference Series ◽

10.1142/s201019451301115x ◽

2013 ◽

Vol 23 ◽

pp. 111-114

Author(s):

YUANYUE PAN ◽

NA WANG ◽

CHENGMIN ZHANG

Keyword(s):

Magnetic Field ◽

Neutron Star ◽

Field Strength ◽

Orbital Period ◽

Dipole Radiation ◽

Spin Period ◽

Binary Pulsars ◽

Proportional Relation ◽

Period Derivative ◽

Line Relationship

With accretion of mass from an evolving companion star, a neutron star can be spun up to an equilibrium period, which is set by the Kepler orbital period at the magnetosphere radius, expressed as a proportional relation between the spin period and magnetic field strength. The spin-up line relationship can be also expressed as a relation between period (P) and period derivative (Ṗ) for the pulsars with dipole radiation. All binary pulsars should lie below the spin-up line, if they accrete the sufficient masses from companions. So, we investigate the distribution of isolated and binary pulsars in the period (P) and magnetic field (B) diagram to see their positions relative to the spin-up line. It is found that the eight binary pulsars (of total 172) are above the spin-up line, thus we analyze their properties and present the possible process of their formations.

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Distances to Binary Pulsars and Implications for Tests of General Relativity

International Astronomical Union Colloquium ◽

10.1017/s025292110004224x ◽

1996 ◽

Vol 160 ◽

pp. 513-516

Author(s):

J. F. Bell ◽

M. Bailes

Keyword(s):

General Relativity ◽

Relative Error ◽

Orbital Period ◽

Proper Motion ◽

Tests Of General Relativity ◽

Binary Pulsars ◽

Period Derivative ◽

General Relativistic

AbstractWe propose a new way to measure accurate distances and transverse velocities for some nearby binary pulsars. In many cases the distances will be more accurately determined than is possible by annual parallax, as the relative error decreases ast−5/2. We also note that tests of the general relativistic prediction of orbital period decay of nearby relativistic binary pulsars will be limited to accuracies of a few percent. Nevertheless, PSR B1534+12 observations are consistent with general relativistic predictions if the proper-motion contribution to the orbital period derivative is accounted for.

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Discovery of a soft X-ray lag in the ultraluminous X-ray source NGC 1313 X-1

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/stz3318 ◽

2019 ◽

Vol 491 (4) ◽

pp. 5172-5178 ◽

Cited By ~ 4

Author(s):

E Kara ◽

C Pinto ◽

D J Walton ◽

W N Alston ◽

M Bachetti ◽

...

Keyword(s):

Time Scales ◽

Timing Analysis ◽

Lag Time ◽

Accretion Disc ◽

Causal Connection ◽

Energy Bands ◽

X Ray ◽

Accretion Flow ◽

Radiative Processes ◽

The Third

ABSTRACT Ultraluminous X-ray sources (ULXs) provide a unique opportunity to probe the geometry and energetics of super-Eddington accretion. The radiative processes involved in super-Eddington accretion are not well understood, and so studying correlated variability between different energy bands can provide insights into the causal connection between different emitting regions. We present a spectral-timing analysis of NGC 1313 X-1 from a recent XMM–Newton campaign. The spectra can be decomposed into two thermal-like components, the hotter of which may originate from the inner accretion disc, and the cooler from an optically thick outflow. We find correlated variability between hard (2–10 keV) and soft (0.3–2 keV) bands on kilosecond time-scales, and find a soft lag of ∼150 s. The covariance spectrum suggests that emission contributing to the lags is largely associated with the hotter of the two thermal-like components, likely originating from the inner accretion flow. This is only the third ULX to exhibit soft lags. The lags range over three orders of magnitude in amplitude, but all three are ∼5–20 per cent of the corresponding characteristic variability time-scales. If these soft lags can be understood in the context of a unified picture of ULXs, then lag time-scales may provide constraints on the density and extent of radiatively driven outflows.

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A high-mass-ratio red-dwarf contact binary with an extremely cool close-in red dwarf

Publications of the Astronomical Society of Japan ◽

10.1093/pasj/psz113 ◽

2019 ◽

Cited By ~ 3

Author(s):

Xiao-Hui Fang ◽

Shengbang Qian ◽

Miloslav Zejda ◽

Soonthornthum Boonrucksar ◽

Xiao Zhou ◽

...

Keyword(s):

Orbital Period ◽

Light Curves ◽

High Mass ◽

Mass Ratio ◽

Third Body ◽

Dynamical Interaction ◽

The Third ◽

Short Period ◽

Contact Binaries ◽

Mass Component

Abstract 1SWASP J161335.80$-$284722.2 (hereafter J161335) is an eclipsing red-dwarf binary with an orbital period of $0.229778\:$d, which is around the short-period limit for contact binaries. Three sets of multi-color light curves of J161335 were obtained from different telescopes in 2015 and 2016 and are analyzed using the Wilson–Devinney method. We discovered that the system is a W-type contact system with a contact degree of 19% and a high mass ratio of 0.91. By using all available eclipse times, we found that the observed $-$ calculated $(O-C)$ diagram displays a cyclic oscillation with an amplitude of 0.00196($\pm 0.00006)\:$d and a period of 4.79($\pm 0.14)\:$yr while it undergoes a downward parabolic change. This downward variation corresponds to a continuous decrease in the orbital period at a rate of $dP/dt = -4.26(\pm$0.01) $\times$ 10$^{-7}\:$d$\:$yr$^{-1}$. The small-amplitude oscillation is explained as the light travel-time effect from the gravitational influence of a third body with a lowest mass of $M _{3}$ = 0.15($\pm 0.01)M_{\,\odot }$. In solving the light curves, we found that the third light is increasing, with the wavelength suggesting that the third body may be a cool red dwarf. This is in agreement with the results obtained by analyzing the $O-C$ diagram. The tertiary red dwarf is orbiting the central red-dwarf binary at an orbital separation of 2.8($\pm 0.2$) au. These results suggest that the J161335 system may be formed through early dynamical interaction where the original low-mass component was replaced by a higher-mass third body and the lower-mass component was kicked out to a wider orbit. In this way, a hierarchical triple system similar to J161335 with a high-mass-ratio binary and a small close-in third body is formed.

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Cyclic Period Changes in the Algol WW Cygni

International Astronomical Union Colloquium ◽

10.1017/s0252921100152029 ◽

2004 ◽

Vol 194 ◽

pp. 87-88

Author(s):

R. T. Zavala ◽

B. J. McNamara ◽

T. E. Harrison ◽

H. Bogue ◽

H. L. Maness

Keyword(s):

Orbital Period ◽

Period Change ◽

Close Binaries ◽

Cyclic Change ◽

Optical Interferometer ◽

Third Body ◽

Magnetic Cycle ◽

Color Changes ◽

The Third ◽

Algol System

AbstractYear to decade-long cyclic period changes have been observed in many classes of close binaries. The Algol binary WW Cygni shows a cyclic change in its orbital period with an amplitude of slightly more than 0.02 days and a period of 56 years. A hypothetical third or fourth body does not satisfactorily explain the observed variation in the orbital period. The change in luminosity and color of the system at primary eclipse minimum are in agreement with the model proposed by Applegate for a magnetic cycle induced period change in WW Cygni. We have commenced monitoring 9 close binaries for evidence of the luminosity and color changes consistent with the magnetic cycle hypothesis. δ Librae is suggested as a case suitable for observation with an optical interferometer to test the third body proposed for this Algol system.

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A Bright Spot and a Serendipitous Stellar Flare on the Contact-Binary VW Cep

International Astronomical Union Colloquium ◽

10.1017/s0252921100096536 ◽

1983 ◽

Vol 71 ◽

pp. 481-483

Author(s):

K.E. Egge ◽

B.R. Pettersen

Keyword(s):

Orbital Period ◽

Triple System ◽

Bright Spot ◽

Stellar Flare ◽

Flare Event ◽

Main Contributor ◽

The Third ◽

Contact Binary ◽

Photoelectric Observations ◽

Large Flare

Almost twenty years ago a large flare event was observed on the prototype contact binary W UMa by Kuhi (1964). Similar events have been reported on 44 i Boo (Eggen 1948) and U Peg (Huruhata 1952) . In this paper we present photoelectric observations at three wavelengths of a flare on VW Cep. This is the first event of this kind to be reported for this star. VW Cep is a triple system. The main contributor to the visual flux is the eclipsing binary, consisting of a Kl primary and a G6 secondary (Kopal 1978), classified to be in contact. The orbital period is 6h 41m. Seven per cent of the total flux in the visual filter is due to the third component, a late K type dwarf at a distance of 12 AU from the eclipsing system (Hershey 1975).

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The binary millisecond pulsar PSR J1023+0038 – II. Optical spectroscopy

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/stz1652 ◽

2019 ◽

Vol 488 (1) ◽

pp. 198-212 ◽

Cited By ~ 1

Author(s):

T Shahbaz ◽

M Linares ◽

P Rodríguez-Gil ◽

J Casares

Keyword(s):

Radial Velocity ◽

Optical Spectroscopy ◽

State Transition ◽

High Energy ◽

Accretion Disc ◽

Millisecond Pulsar ◽

Mass Ratio ◽

Time Resolved ◽

Type Change ◽

Model Predictions

ABSTRACT We present time-resolved optical spectroscopy of the ‘redback’ binary millisecond pulsar system PSR J1023+0038 during both its radio pulsar (2009) and accretion disc states (2014 and 2016). We provide observational evidence for the companion star being heated during the disc state. We observe a spectral type change along the orbit, from ∼G5 to ∼F6 at the secondary star’s superior and inferior conjunction, respectively, and find that the corresponding irradiating luminosity can be powered by the high-energy accretion luminosity or the spin-down luminosity of the neutron star. We determine the secondary star’s radial velocity semi-amplitude from the metallic (primarily Fe and Ca) and Hα absorption lines during these different states. The metallic and Hα radial velocity semi-amplitude determined from the 2009 pulsar-state observations allows us to constrain the secondary star’s true radial velocity K2 = 276.3 ± 5.6 km s−1 and the binary mass ratio q = 0.137 ± 0.003. By comparing the observed metallic and Hα absorption-line radial velocity semi-amplitudes with model predictions, we can explain the observed semi-amplitude changes during the pulsar state and during the pulsar/disc-state transition as being due to different amounts of heating and the presence of an accretion disc, respectively.

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A Beat Phenomenon in Dwarf Nova Eruptions

International Astronomical Union Colloquium ◽

10.1017/s0252921100069396 ◽

1977 ◽

Vol 42 ◽

pp. 227-233

Author(s):

N. Vogt

Keyword(s):

Mass Transfer ◽

Orbital Period ◽

Transfer Rate ◽

Convection Zone ◽

Mass Transfer Rate ◽

Accretion Disc ◽

Light Curves ◽

Dwarf Nova ◽

Beat Phenomenon ◽

Photoelectric Observations

Photoelectric observations of the dwarf nova VW Hyi, obtained at the end of the December 1975 supermaximum, are presented. After decline from the outburst, the superhump period (0ḍ07622) combines with the orbital period (0ḍ07427) to a beat phenomenon: the O-C’s and the light curves of the orbital hump vary systematically with the phase of the beat period for at least one week after recovery from the supermaximum. It is suggested that the red secondary component, which rotates non-synchroneously with the superhump period, expands slightly at the beginning of a supermaximum and is heated up asymmetrically, probably due to instabilities in its convection zone. In addition, the increased mass transfer rate may trigger the long eruption in the accretion disc while short eruptions originate in the disc without participation of the secondary.

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