periastron

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Related to periastrons: Apastron

per·i·as·tron

 (pĕr′ē-ăs′trən, -trŏn)
n. pl. per·i·as·tra (-trə)
The point at which an object is closest to the center of mass of the star it is orbiting.

[peri- + Greek astron, star (probably on the model of perihelion); see ster- in Indo-European roots.]
American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

periastron

(ˌpɛrɪˈæstrɒn)
n
(Astronomy) astronomy the point in the orbit of a body around a star when it is nearest to the star, esp applied to double-star systems
Collins English Dictionary – Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014

periastron

The point in the orbit of an object around a star at which the object is at its closest to the star.
Dictionary of Unfamiliar Words by Diagram Group Copyright © 2008 by Diagram Visual Information Limited
Translations
Periastron
périastre
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References in periodicals archive ?
General relativity predicts that, like the precession of the perihelion of Mercury, the periastron of the pulsar (the point of its closest approach to the black hole) will precess in the plane of its orbit, at rates that are highly sensitive to the orbital parameters, from more than 4 degrees per year for an eccentricity of 0.9 and a semimajor axis of 0.1 AU, to only a few seconds of arc per year for an eccentricity of 0.8 and a semimajor axis of 3 AU.
This effect is even more sensitive to the orbital parameters than the periastron precession is.
Evaluating the periastron power formula for various orbital parameters of black hole-pulsar systems gives a power level 6 times the corresponding Hulse-Taylor power level for a pulsar-black hole orbit with a semimajor axis of 0.1 AU and an eccentricity of 0.9, but only one fifth the Hulse-Taylor level for the same semimajor axis and an eccentricity of 0.8.