Evolution of the barycentric distance of C/2025 R3 (PANSTARRS); zero instant of time, epoch JDTDB 2461041.5, 2026 January 1. Values of the barycentric distance as a function of the velocity parameter 3 Myr into the past (left panel) and the future (right panel) for 250 control orbits. The velocity parameter is the difference between the barycentric and escape velocities at the computed barycentric distance in units of the escape velocity. In the left panel, positive values of the velocity parameter identify control orbits that could be the result of capture from outside the solar system (90.8%). The thick black line corresponds to the aphelion distance—a(1 + e), limiting case e = 1—that defines the domain of dynamically old comets (i.e., those with a⁻¹ > 2.5 × 10⁻⁵ au⁻¹, see M. Królikowska & P. A. Dybczyński 2017); the thick red line signals the radius of the Hill sphere of the solar system (see, e.g., G. A. Chebotarev 1965).