Constraining MOND Using the Vertical Motion of Stars in the Solar Neighborhood

TL;DR

This paper proposes using the vertical motions of stars in the Solar neighborhood to test and constrain Modified Newtonian Dynamics (MOND) theories, highlighting the potential of upcoming Gaia data for more stringent tests.

Contribution

It introduces a novel method to constrain MOND theories by analyzing stellar vertical motions and discusses the potential of future Gaia data for improved constraints.

Findings

Current Hipparcos data provides marginal constraints on MOND.

Future Gaia data can significantly tighten these constraints.

Vertical stellar motions are sensitive indicators for testing gravity theories.

Abstract

Stars with a different vertical motion relative to the galactic disk have a different average acceleration. According to Modified Newtonian Dynamics (MOND) theories they should therefore have a different average orbital velocity while revolving around the Milky Way. We show that this property can be used to constrain MOND theories by studying stars in the local neighborhood. With the {\sc Hipparcos} dataset we can only place marginal constraints. However, the forthcoming {\sc GAIA} catalogue with its significantly fainter cutoff should allow placing a stringent constraint.