English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Plus monthly

Global: Zendy Tools annual

Global: Zendy Tools monthly

Global: Zendy Free Plan

A general study of the stability of equatorial circular orbits in staticaxially symmetric gravitating systems is presented. Important circulargeodesics as the marginally stable orbit, the marginally bounded orbit and thephoton orbit are analyzed. We found general expressions for the radius,specific energy, specific angular momentum and the radius of the marginallystable orbit, both for null and timelike circular geodesics. Solutionsexpressed in cylindrical coordinates, oblate spheroidal coordinates, andprolate spheroidal coordinates are considered. We show that all null circularorbits are unstable and that there are not marginally stable null geodesics,whereas that for timelike geodesics the orbits can be unbounded, bounded orcirculars.

Stability of equatorial circular geodesics in static axially symmetric spacetimes