Astrophysics (Index)About

wide binaries

(WB)
(binary stars thousands of AU apart)

Wide binaries refers to binary stars that are orbiting each other, yet thousands of AU distant from each other: one criteria is "on the order of 7000 AU". By this criteria, Alpha Centauri (including Proxima Centauri) comprises a wide binary. Wide binaries have gained interest as offering tests of gravitational models, including Newtonian gravity and general relativity (GR), along with the theory of dark matter.

The visible portion of galaxies and galaxy clusters do not follow these gravitational models without assuming there is matter that has not been detected (for which he term dark matter has been coined). Galaxies and galaxy clusters are the largest scale gravitationally-bound objects available for analysis to explore this. If gravity has some other pattern at large scales (i.e., different than Newtonian and GR), then the analysis of intervening scales are of interest, such as the scale of wide binaries. Stellar clusters promise to be of similar use.

Studies have claimed that wide binaries do not fit the concept of dark matter, based upon orbital speeds that are faster than can be explained by GR or Newtonian gravity, yet should not be affected by dark matter. Such a high relative velocity could merely indicate the pair are not actually bound, but changes in their relative velocity over time could prove that they are indeed bound. Also, given a set of apparent wide binaries, statistics might indicate a certain percentage are likely to be gravitationally bound.

The abbreviation PHWB has been used for planet-hosting wide binaries.


(binary stars,star type)
Further reading:
https://ui.adsabs.harvard.edu/abs/2012EPJC...72.1884H/abstract
https://ui.adsabs.harvard.edu/abs/2023OJAp....6E...4P/abstract
https://ui.adsabs.harvard.edu/abs/2023A%26A...675A.180G/abstract
https://ui.adsabs.harvard.edu/abs/2023MNRAS.tmp.2250H/abstract
https://arxiv.org/abs/2209.08100

Referenced by page:
modified Newtonian dynamics (MOND)

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