The orbital eccentricities of binary millisecond pulsars in globular clusters

Frederic A. Rasio; Douglas C. Heggie

doi:10.1086/187907

The orbital eccentricities of binary millisecond pulsars in globular clusters

Frederic A. Rasio^*, Douglas C. Heggie

^*Corresponding author for this work

Physics and Astronomy

Research output: Contribution to journal › Article › peer-review

53 Scopus citations

Abstract

Low-mass binary millisecond pulsars (LMBPs) are born with very small orbital eccentricities, typically of order e_i ∼ 10^-6-10^-3. In globular clusters, however, higher eccentricities e_f ≫ e_i can be induced by dynamical interactions with passing stars. Here we show that the cross section for this process is much larger than previously estimated. This is because, even for initially circular binaries, the induced eccentricity e_f for an encounter with percenter separation r_p beyond a few times the binary semimajor axis a declines only as a power law, e_f ∝ (r_p/a)^-5/2, and not as an exponential. We find that all currently known LMBPs in clusters were probably affected by interactions, with their current eccentricities typically greater than at birth by an order of magnitude or more.

Original language	English (US)
Pages (from-to)	L133-L135
Journal	Astrophysical Journal
Volume	445
Issue number	2 PART 2
DOIs	https://doi.org/10.1086/187907
State	Published - Jun 1 1995

Keywords

Binaries: close
Celestial mechanics, stellar dynamics
Globular clusters: general
Pulsars: general

ASJC Scopus subject areas

Astronomy and Astrophysics
Space and Planetary Science

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10.1086/187907

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title = "The orbital eccentricities of binary millisecond pulsars in globular clusters",

abstract = "Low-mass binary millisecond pulsars (LMBPs) are born with very small orbital eccentricities, typically of order ei ∼ 10-6-10-3. In globular clusters, however, higher eccentricities ef ≫ ei can be induced by dynamical interactions with passing stars. Here we show that the cross section for this process is much larger than previously estimated. This is because, even for initially circular binaries, the induced eccentricity ef for an encounter with percenter separation rp beyond a few times the binary semimajor axis a declines only as a power law, ef ∝ (rp/a)-5/2, and not as an exponential. We find that all currently known LMBPs in clusters were probably affected by interactions, with their current eccentricities typically greater than at birth by an order of magnitude or more.",

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T1 - The orbital eccentricities of binary millisecond pulsars in globular clusters

AU - Rasio, Frederic A.

AU - Heggie, Douglas C.

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N2 - Low-mass binary millisecond pulsars (LMBPs) are born with very small orbital eccentricities, typically of order ei ∼ 10-6-10-3. In globular clusters, however, higher eccentricities ef ≫ ei can be induced by dynamical interactions with passing stars. Here we show that the cross section for this process is much larger than previously estimated. This is because, even for initially circular binaries, the induced eccentricity ef for an encounter with percenter separation rp beyond a few times the binary semimajor axis a declines only as a power law, ef ∝ (rp/a)-5/2, and not as an exponential. We find that all currently known LMBPs in clusters were probably affected by interactions, with their current eccentricities typically greater than at birth by an order of magnitude or more.

AB - Low-mass binary millisecond pulsars (LMBPs) are born with very small orbital eccentricities, typically of order ei ∼ 10-6-10-3. In globular clusters, however, higher eccentricities ef ≫ ei can be induced by dynamical interactions with passing stars. Here we show that the cross section for this process is much larger than previously estimated. This is because, even for initially circular binaries, the induced eccentricity ef for an encounter with percenter separation rp beyond a few times the binary semimajor axis a declines only as a power law, ef ∝ (rp/a)-5/2, and not as an exponential. We find that all currently known LMBPs in clusters were probably affected by interactions, with their current eccentricities typically greater than at birth by an order of magnitude or more.

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KW - Celestial mechanics, stellar dynamics

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KW - Pulsars: general

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The orbital eccentricities of binary millisecond pulsars in globular clusters

Abstract

Keywords

ASJC Scopus subject areas

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