periastron


Also found in: Dictionary, Thesaurus, Medical, Wikipedia.
Related to periastron: periapsis, Pericenter

periastron

(pĕr'ēăs`trən): see apsisapsis
(pl. apsides), point in the orbit of a body where the body is neither approaching nor receding from another body about which it revolves. Any elliptical orbit has two apsides.
..... Click the link for more information.
.

periastron

(pe-ree-ass -tron) The closest approach of the two components of a binary star. At greatest separation the components are at apastron.

Periastron

 

the point in the orbit of a star nearest the primary star around which it is revolving. If the influence of other celestial bodies is negligible, motion conforms to Kepler’s laws of planetary motion. Perturbations, caused by the attraction of a third star or by the aspherical nature of the star’s shape, result in variations in the position of the periastron in space.

periastron

[¦per·ē¦as·trən]
(astronomy)
The coordinates and time when the two stars of a binary star system are nearest to each other in their orbits.
References in periodicals archive ?
We let everyone know that WR 140's periastron passage should be observable with medium-resolution spectrographs on small telescopes.
One problem was that during the months around WR 140's periastron, Cygnus would be near the horizon and setting soon after sunset or, later, rising soon before dawn.
Even so, we acquired data right through periastron in January, as spectra were taken by others on clear nights in Germany and England when clouds covered Teide--an unexpected switch
Taylor notes that the date of periastron was not well determined in 1836, and there remains an uncertainty of perhaps a month this time around.
Mass transfer also may have taken place during the 1997-98 periastron event, albeit on a far less dramatic scale, say several astronomers.
If the binary-star model is right, the rapid velocity changes that take place during periastron in an eccentric orbit may just be discernable in the Hubble spectra, obtained with the Space Telescope Imaging Spectrograph, or STIS.
By watching the binary before and after its February 2001 periastron, the team found that "a bow-shock arc of dust is seen within one month of periastron," says Monnier.
Unfortunately, in August the Epsilon Eridani planet was close to periastron [its orbital point closest to the star], which of course makes it harder to see.
This has revealed a progressive shift in the pulsar's periastron (the point in its orbit where it gets closest to its companion).