[ti:Scientists Release New Information about Area near Fomalhaut Star]
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[00:00.04]Scientists have released new information
[00:04.00]about an area around a bright star
[00:07.48]called Fomalhaut in the Milky Way galaxy.
[00:12.28]The observations, made by the James Webb Space Telescope,
[00:17.64]provide details about three rings,
[00:20.96]or belts, of debris orbiting Fomalhaut.
[00:25.80]Fomalhaut, one of the brightest stars in our night sky,
[00:30.68]is about 25 light years from Earth.
[00:35.08]A light year is the distance light travels in a year,
[00:39.28]about 9.5 trillion kilometers.
[00:43.88]Researchers first discovered a belt of debris around Fomalhaut in 1983.
[00:51.88]The Webb found two other rings nearer to the star -
[00:56.40]a bright inner one and a narrow middle one.
[01:01.08]These three belts appear to be populated
[01:04.40]by solid objects called planetesimals.
[01:08.96]Some planetesimals are thought to join together
[01:12.56]early in a star system's history to form planets,
[01:16.92]while others remain as debris like asteroids and comets.
[01:22.40]Andras Gaspar of the University of Arizona
[01:26.80]was the lead author of the study published in Nature Astronomy.
[01:32.80]"Much like our solar system,
[01:34.92]other planetary systems harbor disks of asteroids and comets -
[01:40.84]leftover planetesimals from the epoch of planet formation -
[01:46.40]that continuously grind themselves down" during collisions, he said.
[01:52.56]Fomalhaut is 16 times brighter than the sun
[01:56.56]and almost twice as massive.
[02:00.04]It is about 440 million years old -
[02:03.56]less than a tenth the age of the sun -
[02:06.72]but is probably almost halfway through its life.
[02:11.12]The three belts surround Fomalhaut
[02:14.24]from as far as 23 billion kilometers away.
[02:19.00]That is about 150 times the distance of Earth to the sun.
[02:24.48]While no planets have been discovered yet around Fomalhaut,
[02:29.08]the researchers suspect the belts
[02:31.88]were created by gravitational forces of planets.
[02:36.76]Our solar system has two such belts -
[02:40.32]the main asteroid belt between Mars and Jupiter,
[02:44.48]and the Kuiper belt beyond Neptune.
[02:48.56]The gravitational influence of Jupiter,
[02:51.68]our solar system's largest planet, affects the main asteroid belt.
[02:57.92]Neptune's gravitational influence
[03:00.60]shapes the inner edge of the Kuiper belt.
[03:04.56]Gaspar said that observations of Fomalhaut
[03:08.32]suggest the presence of a huge icy planet in the system.
[03:14.00]Debris belts could offer information about planetary beginnings.
[03:19.84]"Understanding this formation process
[03:22.60]requires a complete understanding
[03:25.16]of how these disks form and evolve,"
[03:28.52]said study co-author Schuyler Wolff.
[03:32.44]There are many open questions
[03:34.64]about the dust in the disks, the scientist added.
[03:39.16]Debris disks are the remains of a planet formation process, Wolff said,
[03:45.84]so their structure can provide valuable information
[03:49.88]about the underlying planet population and history.
[03:55.24]I'm John Russell. 更多听力请访问21VOA.COM