Supercritical accretion in the evolution of neutron star binaries and its implications

Lee, Chang-Hwan; Cho, Hee-Suk

doi:10.1016/j.nuclphysa.2014.04.019

Cited by 9 publications

(13 citation statements)

References 22 publications

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“…Moreno Méndez et al [16] further discussed the consequences of black hole spins in soft X-ray transient sources to gamma-ray bursts and hypernovae. Based on the success of the evolution of black hole binaries, Lee and Cho [17] applied the same common envelope evolution [13] to the evolution of neutron star binaries. The key ingredient in their scenario is the super-Eddington accretion during the common envelope evolution.…”

Section: Evolution Of Neutron Star Binariesmentioning

confidence: 99%

“…The hypothesis of super-Eddington accretion with an accretion rate of 10 ∼ 100 times of the standard Eddington accretion rate, have been discussed in the literature [18] and it is considered to be the origin of some of ultraluminous Xray sources [19]. In this work, we assume that the super-Eddington accretion is hold during the common envelope phase in which the primary (first-born) neutron star spirals into the expanding envelope of a companion star [17,20].…”

Section: Evolution Of Neutron Star Binariesmentioning

confidence: 99%

“…In order to understand the distribution of neutron star mass for a binary population, one has to take into account the evolution of neutron star binary progenitors [17,20]. Since we are interested in neutron star binaries, we only consider a case in which the mass of more massive progenitor in a binary is large enough to produce a neutron star at the end of its evolution.…”

Section: Evolution Of Neutron Star Binariesmentioning

confidence: 99%

“…• Case 2: ∆M ≤ 4% If the mass difference is not negligible even though ∆M ≤ 4%, the secondary companion is already in H-shell burning stage when the primary neutron star is formed [17]. There is no time for the accretion during H-shell burning stage and the neutron star can accrete When the mass difference is large enough, the more massive giant produces a neutron star while the less massive companion is still in main sequence.…”

Section: Evolution Of Neutron Star Binariesmentioning

confidence: 99%

“…In close binaries, the primary neutron star goes into the expanding envelope of the companion and has chances for the extra accretion after its formation. Lee and Cho [17] estimated that the primary neutron star can accrete up to ∼ 1M . When the evolution is finished, the companion can also produce a compact star, i.e., a white dwarf or a neutron star.…”

Section: Evolution Of Neutron Star Binariesmentioning

confidence: 99%

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Neutron Star Mass Distribution in Binaries

Lee¹,

Kim

2016

J. Phys.: Conf. Ser.

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Abstract. Massive neutron stars with ∼ 2M have been observed in neutron star-white dwarf binaries. On the other hand, well-measured neutron star masses in double-neutron-star binaries are still consistent with the limit of 1.5M . These observations raised questions on the neutron star equations of state and the neutron star binary evolution processes. In this presentation, a hypothesis of super-Eddington accretion and its implications are discussed. We argue that a 2M neutron star is an outcome of the super-Eddington accretion during the evolution of neutron star-white dwarf binary progenitors. We also suggest the possibility of the existence of new type of neutron star binary which consists of a typical neutron star and a massive compact companion (high-mass neutron star or black hole) with M ≥ 2M . Neutron Star Mass ObservationsNeutron stars provide opportunities to investigate physics of low-temperature dense Quantum chromodynamics (QCD) matter and are sources of gravitational waves that can be detected by ground-based observatories such as LIGO[1], Virgo [2,3] and KAGRA [4].The central densities of neutron stars are expected to reach several times the normal nuclear matter saturation density (2.04 × 10 14 g cm −3 ). Many theoretical investigations provide massradius relations of neutron stars based on the predicted neutron star equations of state. However, due to the nature of strong interaction which governs the QCD matter, the inner structure of neutron stars are still unknown and the maximum mass of neutron star is still an open question [5]. Until 2010, no firm evidence of a high-mass (≥ 2M ) neutron star has been found. Highmass neutron stars were listed in the X-ray binary catalogue, but they were not taken as the evidences of the existence of high-mass neutron stars due to the large uncertainties. The main uncertainty in mass estimates of X-ray binaries lies in finding the actual gravitational center of companion stars. The situation has been changed due to discoveries of two ∼ 2M neutron stars in neutron star-white dwarf binaries [6,7]. These observations rule out many neutron star equations of state which predict the maximum mass of a neutron star to be less than 2M . Recently, we investigated many equations of state that predict a larger neutron star maximum mass than 2M [8,9,10]. Double-neutron-star binaries are major sources for the neutron star mass measurements and gravitational-wave detections with current ground-based gravitational-wave observatories [11,12]. All well-measured neutron star masses in double-neutron-star binaries are still less than 1.5M , contrary to the recent 2M observation in neutron star-white dwarf binaries. These observations indicate that a neutron star's mass may depend on the evolutionary processes. In this presentation, we discuss a hypothesis of super-Eddington accretion during the evolution of binary progenitors.

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Section: Evolution Of Neutron Star Binariesmentioning

confidence: 99%

Section: Evolution Of Neutron Star Binariesmentioning

confidence: 99%

Section: Evolution Of Neutron Star Binariesmentioning

confidence: 99%

Section: Evolution Of Neutron Star Binariesmentioning

confidence: 99%

Section: Evolution Of Neutron Star Binariesmentioning

confidence: 99%

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Neutron Star Mass Distribution in Binaries

Lee¹,

Kim

2016

J. Phys.: Conf. Ser.

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An accreting low magnetic field magnetar for the ultraluminous X-ray source in M82

Tong

2015

Res. Astron. Astrophys.

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One ultraluminous X-ray source in M82 is identified as an accreting neutron star recently (named as NuSTAR J095551+6940.8). It has a super-Eddington luminosity and is spinning up. For an aged magnetar, it is more likely to be a low magnetic field magnetar. An accreting low magnetic field magnetar may explain both the super-Eddington luminosity and the rotational behavior of this source. Considering the effect of beaming, the spin-up rate is understandable using the traditional form of accretion torque. The transient nature, spectral properties of M82 X-2 are discussed. The theoretical period range of accreting magnetar is provided. Three observational appearances of accreting magnetars are summarized.

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