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dc.contributor.authorBanik, Indranil
dc.contributor.authorKroupa, Pavel
dc.identifier.citationBanik , I & Kroupa , P 2019 , ' Directly testing gravity with Proxima Centauri ' , Monthly Notices of the Royal Astronomical Society , vol. 487 , no. 2 , pp. 1653-1661 .
dc.identifier.otherORCID: /0000-0002-4123-7325/work/101218060
dc.descriptionFunding Information: IB is supported by an Alexander von Humboldt postdoctoral fellowship.en
dc.description.abstractThe wide binary orbit of Proxima Centauri around α Centauri A and B differs significantly between Newtonian and Milgromian dynamics (MOND). By combining previous calculations of this effect with mock observations generated using a Monte Carlo procedure, we show that this prediction can be tested using high precision astrometry of Proxima Centauri. This requires ≈10 yr of observations at an individual epoch precision of 0.5 μas, within the design specifications of the proposed Theia mission. In general, the required duration should scale as the 2/5 power of the astrometric precision. A long-period planet could produce a MOND-like astrometric signal, but only if it has a particular ratio of mass to separation squared and a sky position close to the line segment connecting Proxima Centauri with α Centauri. Uncertainties in perspective effects should be small enough for this test if the absolute radial velocity of Proxima Centauri can be measured to within ≈10 ms-1, better than the present accuracy of 32 ms-1. We expect the required improvement to become feasible using radial velocity zero-points estimated from larger samples of close binaries, with the Sun providing an anchor. We demonstrate that possible astrometric microlensing of Proxima Centauri is unlikely to affect the results. We also discuss why it should be possible to find sufficiently astrometrically stable reference stars. Adequately, addressing these and other issues would enable a decisive test of gravity in the currently little explored low acceleration regime relevant to the dynamical discrepancies in galactic outskirts.
dc.relation.ispartofMonthly Notices of the Royal Astronomical Societyen
dc.subjectBinaries: generalen
dc.subjectDark matteren
dc.subjectProper motionsen
dc.subjectSolar neighbourhooden
dc.subjectStars: individual: Proxima Centaurien
dc.subjectQB Astronomyen
dc.subjectQC Physicsen
dc.subjectSpace and Planetary Scienceen
dc.subjectAstronomy and Astrophysicsen
dc.titleDirectly testing gravity with Proxima Centaurien
dc.typeJournal articleen
dc.contributor.institutionUniversity of St Andrews. School of Physics and Astronomyen
dc.description.statusPeer revieweden

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