scholarly journals Intermediate-Mass Binary Pulsars: a New Class of Objects?

1996 ◽  
Vol 160 ◽  
pp. 539-540
Author(s):  
F. Camilo
Keyword(s):  
Radio Telescope ◽  
Orbital Period ◽  
White Dwarf ◽  
Binary Systems ◽  
Intermediate Mass ◽  
Circular Orbits ◽  
Millisecond Pulsars ◽  
New Class ◽  
Binary Pulsars ◽  
The Galaxy

Approximately 4/5 of the ∼ 35 millisecond pulsars known in the disk of the Galaxy are in binary systems. The vast majority of these binary pulsars have (presumed) helium white dwarf companions with massesm2< 0.45 M⊙, spin periodsP< 10 ms, and all are in extremely circular orbits (Fig. 1). In a search for millisecond pulsars with the Arecibo radio telescope, we have recently discovered PSR J1022+1001, a 16.45 ms pulsar in a 7.8 d orbit with a companion that is at least 0.73 M⊙, and is more likely as massive as 0.8−1.0M⊙; and PSR J0621+1002, a 28.85 ms pulsar in an 8.3 d orbit with a companion at least 0.45 M⊙, and more likely withm2≈ 0.54 M⊙. One other system, PSR J2145–0750, hasP= 16.05 ms, orbital periodPb= 6.8 d, andm2≈ 0.50 M⊙(see Table 1).

scholarly journals Superoutbursts and Superhumps of SU UMa Stars

1988 ◽  
Vol 108 ◽  
pp. 238-239
Author(s):  
Yoji Osaki ◽  
Masahito Hirose
Keyword(s):  
Accretion Disk ◽  
Orbital Period ◽  
White Dwarf ◽  
Binary Systems ◽  
Roche Lobe ◽  
Light Curves ◽  
Close Binary ◽  
Dwarf Novae ◽  
Dwarf Nova ◽  
Close Binary Systems

SU UMa stars are one of subclasses of dwarf novae. Dwarf novae are semi-detached close binary systems in which a Roche-lobe filling red dwarf secondary loses matter and the white dwarf primary accretes it through the accretion disk. The main characteristics of SU UMa subclass is that they show two kinds of outbursts: normal outbursts and superoutbursts. In addition to the more frequent narrow outbursts of normal dwarf nova, SU UMa stars exhibit “superoutbursts”, in which stars reach about 1 magnitude brighter and stay longer than in normal outburst. Careful photometric studies during superoutburst have almost always revealed the “superhumps”: periodic humps in light curves with a period very close to the orbital period of the system. However, the most curious of all is that this superhump period is not exactly equal to the orbital period, but it is always longer by a few percent than the orbital period.

scholarly journals Recycling Pulsars: spins, masses and ages

2012 ◽  
Vol 8 (S291) ◽  
pp. 137-140 ◽  
Author(s):  
T. M. Tauris ◽  
M. Kramer ◽  
N. Langer
Keyword(s):  
White Dwarf ◽  
Formation Process ◽  
Intermediate Mass ◽  
Millisecond Pulsars ◽  
X Ray ◽  
Spin Period ◽  
X Ray Binaries

AbstractAlthough the first millisecond pulsars (MSPs) were discovered 30 years ago we still do not understand all details of their formation process. Here, we present new results from Tauris, Langer & Kramer (2012) on the recycling scenario leading to radio MSPs with helium or carbon-oxygen white dwarf companions via evolution of low- and intermediate mass X-ray binaries (LMXBs, IMXBs). We discuss the location of the spin-up line in the PṖ–diagram and estimate the amount of accreted mass needed to obtain a given spin period and compare with observations. Finally, we constrain the true ages of observed recycled pulsars via calculated isochrones in the PṖ–diagram.

scholarly journals The evolution of helium white dwarfs: Applications for millisecond pulsars

2000 ◽  
Vol 177 ◽  
pp. 635-636 ◽  
Author(s):  
T. Driebe ◽  
T. Blöcker ◽  
D. Schönberner
Keyword(s):  
Mass Loss ◽  
White Dwarf ◽  
White Dwarfs ◽  
Binary Systems ◽  
Mass Star ◽  
Theoretical Studies ◽  
Millisecond Pulsar ◽  
Millisecond Pulsars ◽  
Low Mass ◽  
Red Giant

Low-mass white dwarfs with helium cores (He-WDs) are known to result from mass loss and/or exchange events in binary systems where the donor is a low mass star evolving along the red giant branch (RGB). Therefore, He-WDs are common components in binary systems with either two white dwarfs or with a white dwarf and a millisecond pulsar (MSP). If the cooling behaviour of He-WDs is known from theoretical studies (see Driebe et al. 1998, and references therein) the ages of MSP systems can be calculated independently of the pulsar properties provided the He-WD mass is known from spectroscopy.

scholarly journals On the weak magnetic field of millisecond pulsars: does it decay before accretion?

2019 ◽  
Vol 490 (2) ◽  
pp. 2013-2022 ◽  
Author(s):  
Marilyn Cruces ◽  
Andreas Reisenegger ◽  
Thomas M Tauris
Keyword(s):  
Magnetic Field ◽  
White Dwarf ◽  
Binary Systems ◽  
Alternative Hypothesis ◽  
General Distribution ◽  
Ohmic Dissipation ◽  
Millisecond Pulsars ◽  
Standard Scenario ◽  
Field Decay ◽  
The Magnetic Field

ABSTRACT Millisecond pulsars (MSPs) are old, fast spinning neutron stars (NSs) thought to have evolved from classical pulsars in binary systems, where the rapid rotation is caused by the accretion of matter and angular momentum from their companion. During this transition between classical and MSPs, there is a magnetic field reduction of ∼4 orders of magnitude, which is not well understood. According to the standard scenario, the magnetic field is reduced as a consequence of accretion, either through ohmic dissipation or through screening by the accreted matter. We explored an alternative hypothesis in which the magnetic field is reduced through ambipolar diffusion before the accretion. This is particularly effective during the long epoch in which the pulsar has cooled, but has not yet started accreting. This makes the final magnetic field dependent on the evolution time of the companion star and thus its initial mass. We use observed binary systems to constrain the time available for the magnetic field decay based on the current pulsar companion: a helium white dwarf, a carbon–oxygen white dwarf, or another NS. Based on a simplified model without baryon pairing, we show that the proposed process agrees with the general distribution of observed magnetic field strengths in binaries, but is not able to explain some mildly recycled pulsars where no significant decay appears to have occurred. We discuss the possibility of other formation channels for these systems and the conditions under which the magnetic field evolution would be set by the NS crust rather than the core.

scholarly journals Influence of the initial orbital period and accretion efficiency on the low-mass binary evolution

2021 ◽  
pp. 25-30
Author(s):  
J. Petrovic
Keyword(s):  
Mass Transfer ◽  
Orbital Period ◽  
White Dwarf ◽  
Binary Systems ◽  
Evolutionary Models ◽  
Stable Case ◽  
Long Period ◽  
Low Mass ◽  
Orbital Periods ◽  
Binary Evolution

This paper presents detailed evolutionary models of low-mass binary systems (1.25 + 1 M?) with initial orbital periods of 10, 50 and 100 days and accretion efficiency of 10%, 20%, 50%, and a conservative assumption. All models are calculated with the MESA (Modules for Experiments in Stellar Astrophysics) evolutionary code. We show that such binary systems can evolve via a stable Case B mass transfer into long period helium white dwarf systems.

scholarly journals A noninteracting low-mass black hole–giant star binary system

Science ◽  
2019 ◽  
Vol 366 (6465) ◽  
pp. 637-640 ◽  
Author(s):  
Todd A. Thompson ◽  
Christopher S. Kochanek ◽  
Krzysztof Z. Stanek ◽  
Carles Badenes ◽  
Richard S. Post ◽  
...  
Keyword(s):  
Black Hole ◽  
Binary System ◽  
Orbital Period ◽  
Binary Systems ◽  
Photometric Variability ◽  
Giant Star ◽  
Massive Neutron Star ◽  
The Galaxy ◽  
Low Mass ◽  
Star Binary

Black hole binary systems with companion stars are typically found via their x-ray emission, generated by interaction and accretion. Noninteracting binaries are expected to be plentiful in the Galaxy but must be observed using other methods. We combine radial velocity and photometric variability data to show that the bright, rapidly rotating giant star 2MASS J05215658+4359220 is in a binary system with a massive unseen companion. The system has an orbital period of ~83 days and near-zero eccentricity. The photometric variability period of the giant is consistent with the orbital period, indicating star spots and tidal synchronization. Constraints on the giant’s mass and radius imply that the unseen companion is 3.3−0.7+2.8 solar masses, indicating that it is a noninteracting low-mass black hole or an unexpectedly massive neutron star.

scholarly journals Millisecond Pulsar Surveys

1987 ◽  
Vol 125 ◽  
pp. 13-21
Author(s):  
D. C. Backer
Keyword(s):  
Mass Transfer ◽  
Stellar Evolution ◽  
Binary Systems ◽  
Rotation Period ◽  
Millisecond Pulsar ◽  
Millisecond Pulsars ◽  
X Ray ◽  
New Class ◽  
The Past ◽  
Low Mass

In 1982 a new class of pulsars was defined by the discovery of a star with a millisecond rotation period, 1.6 ms. In the past 3.5 years two additional pulsars with millisecond periods have been discovered. The rapid spin of these pulsars is attributed to mass transfer in a low-mass binary progenitor system. This hypothesis is supported by the presence of companions in two of the three millisecond pulsars. These recent discoveries have led both to a deeper understanding of the final stages of stellar evolution in binary systems, and to closer ties between the observational study of neutron stars by radio, optical and X-ray techniques. In addition the millisecond pulsars provide precise astrophysical clocks that can be used to improve the solar-system ephemeredes and to search for a background of gravitational waves that may have been produced in the early stages of the visible universe. Old and ongoing searches for new millisecond pulsars are described in this paper.

scholarly journals Binary Pulsars

1981 ◽  
Vol 95 ◽  
pp. 361-369 ◽  
Author(s):  
Joseph H. Taylor
Keyword(s):  
Radio Frequency ◽  
Neutron Stars ◽  
Binary Systems ◽  
Compact Object ◽  
Eccentric Orbit ◽  
Circular Orbits ◽  
Binary Pulsars ◽  
The Past ◽  
Gravitational Theories ◽  
The Masses

There are now three radio frequency pulsars known to be in binary systems: PSRs 1913+16, 0820+02, and 0655+64. The first of these, discovered in 1974, moves in a tight, highly eccentric orbit with a period of approximately 7h 45m. Its companion has not yet been identified with certainty, but must be a compact object of mass comparable to that of the pulsar. PSRs 0820+02 and 0655+64, recognized as binaries during the past fifteen months, have nearly circular orbits with periods of over three years and about one day, respectively. All three objects are of great interest for the opportunity they provide to measure the masses of neutron stars. In addition, the first has proven to be a useful probe of gravitational theories, and the study of all of them should yield important information concerning the evolution of binary systems and the formation of neutron stars.

scholarly journals Discovery of Eight Recycled Pulsars – The Swinburne Intermediate Latitude Pulsar Survey

2000 ◽  
Vol 177 ◽  
pp. 33-34
Author(s):  
Russell T. Edwards
Keyword(s):  
Orbital Period ◽  
White Dwarf ◽  
Binary Systems ◽  
Integration Time ◽  
Two Systems ◽  
Low Mass ◽  
Average Profile

AbstractWe have conducted a pulsar survey of intermediate Galactic latitudes (5° < |b| < 15°) at 20 cm. The survey has been highly successful, discovering 58 new pulsars, eight of which are recycled, in only ∼14 days of integration time. One pulsar has a very narrow (2° FWHM) average profile for the pulsar’s period (278 ms). The six new recycled binary systems provide valuable information on the formation of white dwarf pulsar binaries. Two systems have massive white dwarf companions (> 0.57 M⊙and > 1.2 M⊙), while another has a low mass (∼ 0.2 M⊙) companion in a 23.3-d orbit, residing the well-known orbital period “gap”.

scholarly journals Timing of Binary Pulsars at Kalyazin, Russia

2004 ◽  
Vol 218 ◽  
pp. 433-434 ◽  
Author(s):  
Yu. P. Ilyasov ◽  
V. V. Oreshko ◽  
V. A. Potapov ◽  
A. E. Rodin
Keyword(s):  
Energy Density ◽  
Gravitational Wave ◽  
High Precision ◽  
Radio Telescope ◽  
Orbital Period ◽  
Binary Pulsar ◽  
Binary Pulsars ◽  
Upper Limits ◽  
Gravitational Wave Background

Regular high-precision timing of the binary pulsars J0613−0200, J1012+5307, J1022+1001, J1640+2224, J1643−1224, J1713+0747, J2145−0750 and the pulsar B1937+21 has been conducted at the Kalyazin (Russia) radio telescope RT-64 at 0.6 GHz over more than 6 years. Several of the pulsars monitored have been found to be good probes for gravitational wave background (GWB) tests, while others, having a shorter orbital period, can be used for establishing a dynamical binary pulsar timescale. Upper limits for the GWB energy density were estimated.

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