© NASA, ESA, and A. Feild and G. Bacon (STScI)
Exocomets plunging toward a young star in the Beta Pictoris Moving Group located 95 light-years from Earth. A Jupiter-size planet is shown in the star's protoplanetary disk of dust and gas.
Exocomets plunging toward a young star in the Beta Pictoris Moving Group located 95 light-years from Earth. A Jupiter-size planet is shown in the star's protoplanetary disk of dust and gas.
The star, known as HD 172555, is approximately 23 million years old and represents the third extrasolar system where astronomers have detected such comets, according to a statement from NASA. They are known as "exocomets" because they're outside Earth's solar system.
The presence of comets falling toward HD 172555 was determined based on observations of nearby gases, which astronomers say are the vaporized remnants of disintegrated comets after they have ricocheted off unseen Jupiter-size planets. The massive planet's gravity catapults the comets into the star in a process known as "gravitational stirring." Similar processes can be seen in our own solar system when sungrazing comets plunge into the sun.
Comment: Such cometary bombardment is not only the feature of an early star system, but can become a cyclical event. Check our 'Fire in the Sky' section for regular reports, and for the historical implications, check out Laura Kinght-Jaczyk's book Comets and the Horns of Moses and Comets and Catastrophes series.