Constrain the upper velocities of aligned transient sources

Determine upper bounds on the velocities of the Palomar transient sources, particularly those producing aligned flashes, using their angular displacements, exposure times, and possible orbital trajectories.

Background

The paper derives lower bounds on the tangential velocities required for a source to traverse observed angular alignments during a photographic exposure. Many of these lower bounds are sub-orbital, while some large alignments are compatible with circular orbital velocities at high altitudes.

However, the analysis does not constrain how fast the sources could actually be moving. Establishing upper limits would help distinguish slowly moving orbital objects from faster objects or alternative explanations for the aligned transient events.

References

While the lower bounds on velocity are generally sub-orbital, the upper limits remain unconstrained; the objects may plausibly be travelling at orbital velocities or significantly higher.

— Modelling Palomar Transients: Constraints from Reflection Geometry and Orbital Altitude  (2609.05105 - Villarroel et al., 4 Sep 2026) in Section 4.4, “Velocity constraints”