MARTIANS (MARs2020, TIANwen and So on) would see more potentially hazardous asteroids than Earthlings

TL;DR

This study predicts that Mars encounters with potentially hazardous asteroids are more frequent than Earth's, suggesting Mars-based observations could detect more PHAs in the near future, including some observable from Earth in 2025.

Contribution

It extends PHA research to Mars, estimating the number and frequency of Mars-CAPHAs and highlighting the potential for future Mars-based and Earth-based observations.

Findings

Mars-CAPHAs are 2.6 times more numerous than Earth-CAPHAs.

Estimated 16,910 Mars-CAPHAs compared to 4,675 Earth-CAPHAs.

Some Mars-CAPHAs will be observable from Earth in 2025.

Abstract

Potentially Hazardous Asteroids (PHAs) are a special subset of Near-Earth Objects (NEOs) that can come close to the Earth and are large enough to cause significant damage in the event of an impact. Observations and researches of Earth-PHAs have been underway for decades. Here, we extend the concept of PHAs to Mars and study the feasibility of detecting Mars-PHAs in the near future. We focus on PHAs that truly undergo close approaches with a planet (dubbed CAPHAs) and aim to compare the actual quantities of Earth-CAPHAs and Mars-CAPHAs by conducting numerical simulations incorporating the Yarkovsky effect, based on observed data of the main asteroid belt. The estimated number of Earth-CAPHAs and Mars-CAPHAs are 4675 and 16910, respectively. The occurrence frequency of Mars-CAPHAs is about 52 per year, which is 2.6 times that of Earth-CAPHAs, indicating significant potential for future Mars-based observations. Furthermore, a few Mars-CAPHAs are predicted to be observable even from Earth around the time of next Mars opposition in 2025.