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Scientists for the first time have spotted a moon-forming region around a planet beyond our solarsystem - a Jupiter-like world surrounded by a disc of gas and dust massive enough that it could spawn three moons the size of the one orbiting Earth.
Finding
- The researchers used the ALMA observatory in Chile's Atacama desert to detect the disc of swirling material accumulating around one of two newborn planets seen orbiting a young star called PDS 70, located 370 light years from Earth.
- More than 4,400 planets have been discovered outside our solar system, called exoplanets.
- No circumplanetary discs had been found until now because all the known exoplanets resided in “mature” – fully developed – solar systems, except the two infant gas planets orbiting PDS 70.
Birth of a moon
- Stars burst to life within clouds of interstellar gas and dust scattered throughout galaxies.
- Leftover material spinning around a new star then coalesces into planets, and circumplanetary discs surrounding some planets similarly yield moons.
- The dominant mechanism thought to underpin planet formation is called “core accretion,” said study co-author Richard Teague of the Harvard-Smithsonian Center for Astrophysics.
- “In this scenario, small dust grains, coated in ice, gradually grow to larger and larger sizes through successive collisions with other grains.
- This continues until the grains have grown to a size of a planetary core, at which point the young planet has a strong enough gravitational potential to accrete gas which will form its atmosphere.
Source: The Hindu
