NASA’s asteroid detection mission may need to expand its search due to new discoveries of asteroids co-orbiting Venus that pose a threat to Earth. Researchers have found 20 known asteroids with this status, but their unpredictability makes them difficult to detect.
A study published in the journal Astronomy and Astrophysics aims to understand how many more co-orbital asteroids exist and how to detect them. The researchers used simulations to model these asteroids’ orbits and found that they can pose a collisional hazard to Earth if they have a minimum diameter of 140 meters and come within 0.05 astronomical units of our planet.
However, the asteroids’ chaotic dynamics make it challenging to predict their orbits. The Lyapunov time refers to how long an object’s orbit becomes unpredictable due to these dynamics, which is around 150 years for co-orbital asteroids. This means that studying a single orbit doesn’t provide much insight into its future behavior.
The researchers created a grid of cloned asteroids with different orbital characteristics and simulated their orbits over 36,000 years. They found that certain orbits with eccentricity below 0.38 pose a collisional hazard to Earth, particularly at lower inclinations.
Detection is further complicated by the Sun’s glare, which limits observations to specific periods throughout the year. To overcome this challenge, the researchers suggest sending a spacecraft to Venus’ orbit to enhance detection capabilities.
The Vera Rubin Observatory may detect some of these asteroids during its regular survey operations, but a dedicated space-based mission near Venus is needed to map and discover all the “invisible” PHA among co-orbital asteroids threatening Earth.
Source: https://www.sciencealert.com/a-serious-threat-may-be-lurking-in-the-orbit-of-venus-says-study