Testing Mars Trojan Origins via Chi-Square Analysis

This study employs the Pearson’s chi-square (𝜒²) test to compare visible and near-infrared (VNIR) reflectance spectra of seven asteroids against approximately 11,000 laboratory spectra from meteoritic, terrestrial, synthetic, Apollo, and Luna samples. First, we validate the technique using three well-studied asteroids - (4) Vesta, (6) Hebe, and (19) Fortuna - to confirm previously established spectral matches.We then apply the 𝜒² test to four Mars Trojans: (5261) Eureka, (101429) 1998 VF31, (311999) 2007 NS2, and (385250) 2001 DH47—asteroids whose compositions are currently under speculation. For asteroids potentially affected by space weathering, reddening effects are removed. The top 𝜒² matches for the Mars Trojans show notable spectral similarities with Martian meteorites and minerals formed by igneous processes, suggesting a possible Martian origin for some of the Mars Trojans;however, the possibility that these bodies could be fragments of a disrupted differentiated parent body cannot be ruled out. This paper highlights the value of the 𝜒² test as a preliminary tool for identifying spectral analogs and exploring possible surface compositions of asteroids.