Scientists Say a Massive Star Has Mysteriously Disappeared
2020-07-06
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1Astronomers say a massive star appears to have mysteriously disappeared from a distant galaxy.
2The star is part of the Kinman Dwarf galaxy, also known as PHL 293B.
3The galaxy is about 75 million light years away from Earth.
4It sits in the constellation of Aquarius.
5A constellation is "a group of stars that forms a particular shape in the sky," the U.S. space agency NASA says.
6Images of the Kinman Dwarf galaxy were captured in the past by a camera attached to NASA's Hubble Space Telescope.
7But since the galaxy is so far away, researchers have not been able to clearly observe its individual stars.
8Astronomers had, however, identified important "signatures," or signs, that the massive star existed.
9Now they are searching for answers about why these signatures can no longer be seen.
10A team of scientists from the European Southern Observatory reported it had been observing the star with its Very Large Telescope, VLT, for at least 10 years.
11The observatory, based in Chile, provides astronomy support to European countries.
12The team said its observations repeatedly showed evidence that the Kinman Dwarf galaxy contained the massive star, estimated to be about 2.5 million times brighter than our sun.
13Researchers said the evidence suggested that the star was "in a late stage of its evolution."
14They added that the star was a kind considered to be "unstable."
15This means it could go through major changes in brightness or lose some of its mass.
16The project's leader was Andrew Allan, a doctoral student in astrophysics at Ireland's Trinity College Dublin.
17He led a study on the findings, recently published in Monthly Notices of the Royal Astronomical Society.
18Allan said the researchers wanted to learn more about how massive stars end their lives.
19The massive object observed in the Kinman Dwarf galaxy seemed like the perfect target.
20But when astronomers turned the Very Large Telescope toward the distant galaxy in 2019, they could no longer find any signatures of the massive star.
21"Instead, we were surprised that the star had disappeared," Allan said in a statement.
22Similar stars that experience major changes usually produce some signatures.
23So the team tried searching several more times using different equipment, but still found no signs of the star.
24"It would be highly unusual for such a massive star to disappear without producing a bright supernova explosion," Allan said.
25NASA describes a supernova as an "extremely bright, super-powerful explosion of a star."
26A supernova takes place at the end of a star's life.
27The astronomers are now exploring two possibilities.
28The first is that the star might have become less bright and could be partly blocked by dust.
29The other possibility is that it collapsed into a black hole without producing a supernova.
30If the star did collapse into a black hole, it would be a highly unusual end, the researchers said.
31"This would be a rare event: our current understanding of how massive stars die points to most of them ending their lives in a supernova," said a statement issued by the European Southern Observatory (ESO).
32Trinity Professor Jose Groh, another project leader, said the astronomers plan to keep observing the galaxy for signs of the mysterious missing star.
33"We will likely need to wait a few years before confirming what fate befell this particular star.
34We will observe the galaxy again with the Hubble Space Telescope next year, which will provide new clues," Groh said.
35The ESO also plans to launch observation equipment and is expecting its Extremely Large Telescope to be in operation by 2025.
36That telescope should be "capable of resolving stars in distant galaxies such as the Kinman Dwarf," the statement said.
37The new equipment could also help astronomers solve the mysteries of the future.
38I'm Bryan Lynn.
1Astronomers say a massive star appears to have mysteriously disappeared from a distant galaxy. 2The star is part of the Kinman Dwarf galaxy, also known as PHL 293B. The galaxy is about 75 million light years away from Earth. It sits in the constellation of Aquarius. A constellation is "a group of stars that forms a particular shape in the sky," the U.S. space agency NASA says. 3Images of the Kinman Dwarf galaxy were captured in the past by a camera attached to NASA's Hubble Space Telescope. But since the galaxy is so far away, researchers have not been able to clearly observe its individual stars. 4Astronomers had, however, identified important "signatures," or signs, that the massive star existed. Now they are searching for answers about why these signatures can no longer be seen. 5A team of scientists from the European Southern Observatory reported it had been observing the star with its Very Large Telescope, VLT, for at least 10 years. The observatory, based in Chile, provides astronomy support to European countries. 6The team said its observations repeatedly showed evidence that the Kinman Dwarf galaxy contained the massive star, estimated to be about 2.5 million times brighter than our sun. 7Researchers said the evidence suggested that the star was "in a late stage of its evolution." They added that the star was a kind considered to be "unstable." This means it could go through major changes in brightness or lose some of its mass. 8The project's leader was Andrew Allan, a doctoral student in astrophysics at Ireland's Trinity College Dublin. He led a study on the findings, recently published in Monthly Notices of the Royal Astronomical Society. 9Allan said the researchers wanted to learn more about how massive stars end their lives. The massive object observed in the Kinman Dwarf galaxy seemed like the perfect target. 10But when astronomers turned the Very Large Telescope toward the distant galaxy in 2019, they could no longer find any signatures of the massive star. "Instead, we were surprised that the star had disappeared," Allan said in a statement. 11Similar stars that experience major changes usually produce some signatures. So the team tried searching several more times using different equipment, but still found no signs of the star. 12"It would be highly unusual for such a massive star to disappear without producing a bright supernova explosion," Allan said. 13NASA describes a supernova as an "extremely bright, super-powerful explosion of a star." A supernova takes place at the end of a star's life. 14The astronomers are now exploring two possibilities. The first is that the star might have become less bright and could be partly blocked by dust. The other possibility is that it collapsed into a black hole without producing a supernova. 15If the star did collapse into a black hole, it would be a highly unusual end, the researchers said. "This would be a rare event: our current understanding of how massive stars die points to most of them ending their lives in a supernova," said a statement issued by the European Southern Observatory (ESO). 16Trinity Professor Jose Groh, another project leader, said the astronomers plan to keep observing the galaxy for signs of the mysterious missing star. 17"We will likely need to wait a few years before confirming what fate befell this particular star. We will observe the galaxy again with the Hubble Space Telescope next year, which will provide new clues," Groh said. 18The ESO also plans to launch observation equipment and is expecting its Extremely Large Telescope to be in operation by 2025. 19That telescope should be "capable of resolving stars in distant galaxies such as the Kinman Dwarf," the statement said. The new equipment could also help astronomers solve the mysteries of the future. 20I'm Bryan Lynn. 21Bryan Lynn wrote this story for VOA Learning English, based on reports from the European Southern Observatory and Trinity College Dublin and NASA. Caty Weaver was the editor. 22We want to hear from you. Write to us in the Comments section, and visit our Facebook page. 23________________________________________________________________ 24Words in This Story 25astronomer - n. a scientist who studies stars and planets 26particular - adj. used to describe a certain part of something 27evolution - n. a gradual process of change and development 28unstable - adj. likely to change or end suddenly 29fate - n. what happens to something, especially something bad 30befall - v. to happen 31clue - n. a piece of information that helps you solve a problem or answer a questions 32resolve - v. to solve or end a problem or difficulty