Birth rate of millisecond pulsars

Lorimer,; Lyne,; Festin,; Nicastro, L.

doi:10.1038/376393a0

Cited by 59 publications

(67 citation statements)

References 10 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…This timescale is especially important in MSP systems and should be added to the optically determined cooling age of the WD to yield the true age of the recycled radio pulsar. Unfortunately, the true age of a recycled pulsar cannot be determined from its characteristic spin-down age as this method has proved unreliable by a factor of 10 or more (Camilo et al 1994;Lorimer et al 1995;Tauris 2012;Tauris et al 2012).…”

Section: Hydrogen Shell Flashes and Proto-wdsmentioning

confidence: 99%

Models of low-mass helium white dwarfs including gravitational settling, thermal and chemical diffusion, and rotational mixing

Istrate

Marchant

Tauris

et al. 2016

A&A

191

321

View full text Add to dashboard Cite

A large number of extremely low-mass helium white dwarfs (ELM WDs) have been discovered in recent years. The majority of them are found in close binary systems suggesting they are formed either through a common-envelope phase or via stable mass transfer in a low-mass X-ray binary (LMXB) or a cataclysmic variable (CV) system. Here, we investigate the formation of these objects through the LMXB channel with emphasis on the proto-WD evolution in environments with different metallicities. We study for the first time the combined effects of rotational mixing and element diffusion (e.g. gravitational settling, thermal and chemical diffusion) on the evolution of proto-WDs and on the cooling properties of the resulting WDs. We present state-of-the-art binary stellar evolution models computed with MESA for metallicities of Z = 0.02, 0.01, 0.001 and 0.0002, producing WDs with masses between ∼0.16−0.45 M . Our results confirm that element diffusion plays a significant role in the evolution of proto-WDs that experience hydrogen shell flashes. The occurrence of these flashes produces a clear dichotomy in the cooling timescales of ELM WDs, which has important consequences e.g. for the age determination of binary millisecond pulsars. In addition, we confirm that the threshold mass at which this dichotomy occurs depends on metallicity. Rotational mixing is found to counteract the effect of gravitational settling in the surface layers of young, bloated ELM proto-WDs and therefore plays a key role in determining their surface chemical abundances, i.e. the observed presence of metals in their atmospheres. We predict that these proto-WDs have helium-rich envelopes through a significant part of their lifetime. This is of great importance as helium is a crucial ingredient in the driving of the κ-mechanism suggested for the newly observed ELM proto-WD pulsators. However, we find that the number of hydrogen shell flashes and, as a result, the hydrogen envelope mass at the beginning of the cooling track, are not influenced significantly by rotational mixing. In addition to being dependent on proto-WD mass and metallicity, the hydrogen envelope mass of the newly formed proto-WDs depends on whether or not the donor star experiences a temporary contraction when the H-burning shell crosses the hydrogen discontinuity left behind by the convective envelope. The hydrogen envelope at detachment, although small compared to the total mass of the WD, contains enough angular momentum such that the spin frequency of the resulting WD on the cooling track is well above the orbital frequency.

show abstract

Section: Hydrogen Shell Flashes and Proto-wdsmentioning

confidence: 99%

Models of low-mass helium white dwarfs including gravitational settling, thermal and chemical diffusion, and rotational mixing

Istrate

Marchant

Tauris

et al. 2016

A&A

191

321

View full text Add to dashboard Cite

show abstract

“…The BMSP J1012+5307 (P orb ' 14:5 hr) has been well studied (Lorimer et al 1995), and its companion has been observed photometrically. Van Kerkwijk et al (1996) determine the effective temperature of the dwarf to be T e ¼ 8550 AE 25 K with an inferred log g ¼ 6:75 AE 0:07.…”

Section: Psr J1012+5307mentioning

confidence: 99%

“…These observations provide us with a unique opportunity to confront spin-down theory with the observations (see, e.g., HPb for a discussion). Lorimer et al (1995) used the spin-period derivative to estimate the pulsar's age (and hence the age of the companion) to be $7 Gyr. HPb, using the envelope masses from IT, estimate the mass of the HeDD to be between 0.13 and 0.21 M and its age to be less than 0.6 Gyr.…”

Section: Psr J1012+5307mentioning

confidence: 99%

Evolutionary Properties of Helium‐rich, Degenerate Dwarfs in Binaries Containing Compact Companions

Nelson

Dubeau

MacCannell

2004

ApJ

110

View full text Add to dashboard Cite

The evolution of binaries containing low-mass donors ( 2 M ) and degenerate accretors (i.e., white dwarfs [0.7 M ] or neutron stars [1.4 M ]) is systematically investigated over a wide expanse of parameter space. The donors are assumed to have metallicities in the range of 0:0001 Z 0:02 and could be either unevolved (zeroage main sequence) or ascending the red giant branch at the onset of mass transfer [corresponding to 5 P P orb (hr) P 2 ; 10 3 ]. The evolutionary tracks form part of a very detailed grid of nearly 200 sequences, each corresponding to a different set of initial conditions. During the initial phases of their evolution, the systems resemble either low-mass X-ray binaries or cataclysmic variables. However, as has been pointed out by several authors (e.g., Podsiadlowski et al.), the evolutionary tracks can exhibit a wide variety of behaviors and outcomes. We focus on systems that evolve to produce helium-rich degenerate dwarfs (HeDDs) that are either detached or still losing mass after a Hubble time. Of the systems that avoid dynamical instability, some evolve to ultrashort values of P orb (<60 minutes), while others that lie above the bifurcation limit (which we show to be quite sensitive to the assumed metallicity) produce wide binary millisecond pulsars (BMSPs) containing HeDD companions that have P orb values of P2 ; 10 4 hr. We also show that the mass and composition of the envelopes of HeDDs that are about to descend the cooling branch are particularly sensitive to the input physics and this in turn dictates whether they experience extremely vigorous hydrogen shell flashes. Our computed values of the envelope mass, m env (corresponding to the mass of those layers below the surface containing some hydrogen), typically have a dependence on the final donor mass (m f ) and metallicity (Z ) that can be expressed as m env / m À2:8 f Z À0:2 . Furthermore, for systems that do not evolve too close to the bifurcation limit, we find that the final orbital period is given by P orb; f (hr) ffi 2:5 Z 0:3 ; 10 10:7ðm f =M Þ. Finally, we use our results to comment on the properties of the optical companions to binary millisecond pulsars and compare their inferred ages with the spindown times of the pulsars. The structure of young HeDDs should be particularly useful as starting models for more sophisticated cooling calculations that take into account important long-term physical processes and thus we are making our models available for retrieval.

show abstract

“…They are presumably young objects, with r c < 5 x 10 8 yr, but youth alone does not imply high radio luminosity, as PSR J1012+5307, very young and of median luminosity (Lorimer et al 1995), suggests. On the other hand there is some debate regarding the age of this pulsar (Alberts et al 1996).…”

Section: Binary and Millisecond Pulsars And Death Linesmentioning

confidence: 97%

Pulsar Period and Magnetic Field Evolution

Camilo¹

1996

International Astronomical Union Colloquium

View full text Add to dashboard Cite

Abstract. One of the important unsolved problems in pulsar astrophysics concerns the formation and evolution of their magnetic fields. We summarize measurements of braking indices and their implications for the spin and magnetic field evolution of young pulsars. An analysis of the period-period derivative diagram suggests one or more of the following: (a) a substantial population of young pulsars remains undiscovered; (b) a large fraction of all slow pulsars may be recycled; (c) magnetic fields in isolated pulsars decay by a factor of a few in the first few million years. We also note that the observed P-P distribution of millisecond pulsars may be shaped by luminosity evolution.

show abstract

Birth rate of millisecond pulsars

Cited by 59 publications

References 10 publications

Models of low-mass helium white dwarfs including gravitational settling, thermal and chemical diffusion, and rotational mixing

Models of low-mass helium white dwarfs including gravitational settling, thermal and chemical diffusion, and rotational mixing

Evolutionary Properties of Helium‐rich, Degenerate Dwarfs in Binaries Containing Compact Companions

Pulsar Period and Magnetic Field Evolution

Contact Info

Product

Resources

About