Why in News? 

Astronomers discovered Arjuna 2025 PN7 (part of Arjuna asteroid class), a new quasi-satellite of Earth, first spotted by Pan-STARRS 1 telescope in Hawaii. 

• Earth's 7th known quasi-satellite (considered quasi-moons), orbiting the Sun in sync with Earth but not gravitationally bound to it. 
  • Quasi-satellites stay in sync with Earth’s orbit for hundreds to thousands of years, unlike mini-moons which orbit Earth temporarily. 
• With a semi-major axis of 1.003 AU (almost identical to Earth’s orbit), it follows a slightly elliptical orbit and has a 1:1 orbital resonance with Earth. 
• Will remain a quasi-satellite for 128 years, offering opportunities to study orbital resonance, gravitational interactions & near-Earth object dynamics and planetary defense research. 
• Arjuna asteroid class includes asteroids with Earth-like orbits, first identified with asteroid 1991 VG.  
• They are among the closest to Earth & can become temporary mini-moons before drifting away.