  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.
