arXiv subjects

Kevin J Napier

Publications and source records attributed to Kevin J Napier.

5 recordsLinked to original sources

arXiv2026

heliostack: A Novel Approach to Minor Planet Discovery

The study of faint solar system objects is a promising avenue for understanding the origin and evolution of planetary systems. However, such objects are difficult to detect in conventional surveys. Here we introduce heliostack, an algorithm for nonlinear shift-and-stack searches for solar system objects, which enables us to combine images taken over longer time spans than was previously possible. Applying this algorithm to a number of existing archival and forthcoming surveys will allow us to maximize their potential for discovering faint solar system objects. In this work, we apply heliostack to archival Hubble Space Telescope (HST) data, completing an exhaustive search for Cold Classical Kuiper Belt Objects in a set of HST images taken over a 15-day time span in 2003. We successfully recover both of the known sub-threshold objects in the data, and add two new discoveries. These two new objects are the first to ever be discovered in stacks of images taken over a time span longer than about one day.

astro-ph.EP↗

arXiv2024

Improved Initial Guesses for Numerical Solutions of Kepler's Equation

Numerical solutions of Kepler's Equation are critical components of celestial mechanics software, and are often computation hot spots. This work uses symbolic regression and a genetic learning algorithm to find new initial guesses for iterative Kepler solvers for both elliptical and hyperbolic orbits. The new initial guesses are simple to implement, and result in modest speed improvements for elliptical orbits, and major speed improvements for hyperbolic orbits.

astro-ph.EP↗

arXiv2024

A Novel Orbit Parameterization in Spherical Coordinates

We present a novel orbit parameterization in spherical coordinates. This parameterization enables the mixing of varying and invariant orbital parameters, and clarifies the physics of the orbit. It also simplifies the process of placing synthetic populations at exactly specified locations on the sky, which is particularly useful for survey design and simulation studies.

astro-ph.EP↗

arXiv2022

Transfer of Rocks between Planetary Systems: Panspermia Revisited

Motivated by the recent discovery of interstellar objects passing through the solar system, and by recent developments in dynamical simulations, this paper reconsiders the likelihood for life bearing rocks to be transferred from one planetary system to another. The astronomical aspects of this lithopanspermia process can now be estimated, including the cross sections for rock capture, the velocity distributions of rocky ejecta, the survival times for captured objects, and the dynamics of the solar system in both its birth cluster and in the field. The remaining uncertainties are primarily biological, i.e., the probability of life developing on a planet, the time required for such an event, and the efficiency with which life becomes seeded in a new environment. Using current estimates for the input quantities, we find that the transfer rates are enhanced in the birth cluster, but the resulting odds for success are too low for panspermia to be a likely occurrence. In contrast, the expected inventory of alien rocks in the solar system is predicted to be substantial (where the vast majority of such bodies are not biologically active and do not interact with Earth).

astro-ph.EP↗

arXiv2021

On the Fate of Interstellar Objects Captured by our Solar System

With the recent discoveries of interstellar objects `Oumuamua and Borisov traversing the solar system, understanding the dynamics of interstellar objects is more pressing than ever. These detections have highlighted the possibility that captured interstellar material could be trapped in our solar system. The first step in rigorously investigating this question is to calculate a capture cross section for interstellar objects as a function of hyperbolic excess velocity, which can be convolved with any velocity dispersion to compute a capture rate (Napier et. al. 2021). Although the cross section provides the first step toward calculating the mass of alien rocks residing in our solar system, we also need to know the lifetime of captured objects. We use an ensemble of N-body simulations to characterize a dynamical lifetime for captured interstellar objects and determines the fraction of surviving objects as a function of time (since capture). We also illuminate the primary effects driving their secular evolution. Finally, we use the resulting dynamical lifetime function to estimate the current inventory of captured interstellar material in the solar system. We find that capture from the field yields a steady state mass of only $\sim 10^{-13} M_{\oplus}$, whereas the mass remaining from capture events in the birth cluster is roughly $10^{-9} M_{\oplus}$.

astro-ph.EP↗