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Post Info TOPIC: Pulsar in a Stellar Triple System
Blobrana


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PSR J0337+1715
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Title: A formation scenario for the triple pulsar PSR J0337+1715: breaking a binary system inside a common envelope
Author: Efrat Sabach, Noam Soker (Technion, Israel)

We propose a scenario for the formation of the pulsar with two white dwarfs (WDs) triple system PSR~J0337+1715 where a close binary system is tidally and frictionally destroyed inside the envelope of a massive star that later goes through an accretion induced collapse (AIC) and forms the neutron star (NS). The proposed scenario includes a new ingredient of a binary system that breaks-up inside a common envelope. One of the two lower mass stars that ends further out transfers mass to the ONeMg WD remnant of the massive star, and triggers the AIC. The inner low mass main sequence star evolves later and spins-up the NS to form a millisecond pulsar. We use the binary_c software and show that both low mass stars end as helium WDs. This scenario is not extremely sensitive to initial conditions. For example, after the low mass binary system breaks loose inside the envelope, the tertiary stellar orbit can have any eccentricity, from a circular to a very eccentric orbit; it will in any case be circularized when the tertiary star turns into a giant. In addition, the secondary star final mass is determined by its core mass during its Hertzsprung gap phase. The proposed scenario employs an efficient envelope removal by jets launched by the compact object immersed in the giant envelope, and the newly proposed grazing envelope evolution.

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Blobrana


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Title: A millisecond pulsar in a stellar triple system
Authors: S. M. Ransom (1), I. H. Stairs (2), A. M. Archibald (3, 4), J. W. T. Hessels (3, 5), D. L. Kaplan (6, 7), M. H. van Kerkwijk (8), J. Boyles (9, 10), A. T. Deller (3), S. Chatterjee (11), A. Schechtman-Rook (7), A. Berndsen (2), R. S. Lynch (4), D. R. Lorimer (9), C. Karako-Argaman (4), V. M. Kaspi (4), V. I. Kondratiev (3, 12), M. A. McLaughlin (9), J. van Leeuwen (3, 5), R. Rosen (1, 9), M. S. E. Roberts (13, 14), K. Stovall (15, 16) ((1) NRAO, (2) U. British Columbia, (3) ASTRON, (4) McGill U., (5) U. Amsterdam, (6) U. Wisconsin-Milwaukee, (7) U. Wisconsin-Madison, (8) U. Toronto, (9) West Virginia U., (10) Western Kentucky U., (11) Cornell U., (12) Lebedev Physical Inst., (13) Eureka Scientific, (14) New York U. at Abu Dhabi, (15) U. Texas at Brownsville, (16) U. New Mexico)

Gravitationally bound three-body systems have been studied for hundreds of years and are common in our Galaxy. They show complex orbital interactions, which can constrain the compositions, masses, and interior structures of the bodies and test theories of gravity, if sufficiently precise measurements are available. A triple system containing a radio pulsar could provide such measurements, but the only previously known such system, B1620-26 (with a millisecond pulsar, a white dwarf, and a planetary-mass object in an orbit of several decades), shows only weak interactions. Here we report precision timing and multi-wavelength observations of PSR J0337+1715, a millisecond pulsar in a hierarchical triple system with two other stars. Strong gravitational interactions are apparent and provide the masses of the pulsar (1.4378(13) Msun, where Msun is the solar mass and the parentheses contain the uncertainty in the final decimal places) and the two white dwarf companions (0.19751(15) Msun and 0.4101(3) Msun), as well as the inclinations of the orbits (both approximately 39.2 degrees). The unexpectedly coplanar and nearly circular orbits indicate a complex and exotic evolutionary past that differs from those of known stellar systems. The gravitational field of the outer white dwarf strongly accelerates the inner binary containing the neutron star, and the system will thus provide an ideal laboratory in which to test the strong equivalence principle of general relativity.

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Blobrana


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RE: Pulsar in a Stellar Triple System
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Triple star system 'can reveal secrets of gravity'

Astronomers have discovered a unique triple star system which could reveal the true nature of gravity.
They found a pulsar with two white dwarfs all packed in a space smaller than Earth's orbit of the Sun.
The trio's unusually close orbits allow precise measurements of gravity and could resolve difficulties with Einstein's theories.
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Blobrana


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Pulsar in a Stellar Triple System Makes Unique Gravitational Laboratory

Astronomers using the National Science Foundation's Green Bank Telescope (GBT) have discovered a unique stellar system of two white dwarf stars and a superdense neutron star, all packed within a space smaller than Earth's orbit around the Sun. The closeness of the stars, combined with their nature, has allowed the scientists to make the best measurements yet of the complex gravitational interactions in such a system.
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