How Do Dying Stars Contribute to the Formation of Planets

How Do Dying Stars Contribute to the Formation of Planets.

Does every star have planets?

The Milky Way galaxy, as seen from Earth.

The Milky way galaxy, equally seen from Earth. Astronomers believe there are effectually one billion stars in the milky way.

(Image credit: Abdul Azis via Getty Images)

In 1992, astronomers discovered the first planet outside the solar system. Since and so, telescopes have spotted thousands of these so-chosen exoplanets orbiting not only stars similar to the dominicus but besides in binary star systems; minor, cool stars called red dwarfs; and even ultradense
neutron stars. It’s enough to make you wonder: Does every star out at that place have at least ane planet orbiting information technology?

In a word, no, said Jonathan Lunine, chair of the Department of Astronomy at Cornell University. That is, at to the lowest degree not every bit far as we know.

“It’s always a question of whether you lot can observe something or not,” Lunine told Live Science. “Ane doesn’t know for certain. But it’s certainly the case that there are plenty of stars where at that place have been searches for planets, and none accept been found to engagement.”


Why are galaxies dissimilar shapes?

Scientists estimate that there are as many planets every bit stars in our galaxy, Lunine said, but those planets aren’t evenly distributed. Some stars — similar the dominicus,
likewise as TRAPPIST-1

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, a cherry dwarf star nigh twoscore low-cal-years away — are home to more than than half a dozen planets, while others may accept none.

But what makes one star host so many planets while others fly solo? Scientists think it stems from the manner the star formed. When immature stars are forming, they’re unremarkably surrounded past a ring of grit particles. These particles crash into each other to form larger and larger clumps, which can eventually class planets. But not all young stars are and so lucky.

“If you lot accept a star which is formed from a dodder of interstellar cloud that happens to have a very rapid rotation, as that clump is contracting instead of spinning out to form a disk, it might break into two or even more than pieces and form a binary star organization or multiple-star arrangement,” Lunine said. “And in those cases, if a disk hasn’t formed, information technology’south possible that the system of ii stars or iii stars never ends up with a planet.”

Binary star systems tin can form planets in some cases — every bit in the case of
Kepler-47 and its 3 planets

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— merely the conditions have to be just correct.

“There are binary star systems where there are planets,” Lunine said. “So do those systems end up with the material breaking into 2 clumps so a disk forming effectually 1 of those clumps, or maybe both of those clumps? Was in that location maybe something that was captured?”

More than rarely, a young star’s dust-filled clump might spin so slowly that information technology simply collapses into a star without ever forming a disk, Lunine said. It’s too possible for a star to form planets but for the intense gravity of another star to slingshot them out of the solar system, or at least transport them too far out to be detected. That may take been what happened to the
planet Hard disk 106906 b

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, which circles a binary star organization at an off-kilter orbit 18 times farther from its star than Pluto is from the sun.

But Lunine warned that our knowledge of how many stars host planets is subject to what we can detect. That’s because many planets are detected using the transit method, which uses dips in a star’s brightness as a telltale sign that a planet is passing in front of information technology.

“We can always wait at a particular star and say, ‘Well, a planet wasn’t detected around it, merely you know, maybe there’s a planet that’s kind of small and actually orbiting far from the star and doesn’t transit the star and therefore is kind of stealthy.’ That’s always a possibility. But more than likely, there are stars that actually don’t have planets around them.”

Originally published on Live Science.

Ashley Hamer is a contributing writer for Live Science who has written nigh everything from space and quantum physics to health and psychology. She’due south the host of two podcasts: Curiosity Daily and Taboo Science. She has also written for the YouTube channels SciShow and It’south Okay to Exist Smart. With a bachelor’s and master’due south degree in jazz saxophone from the University of North Texas, Ashley has an unconventional background that gives her science writing a unique perspective and an outsider’s signal of view.

How Do Dying Stars Contribute to the Formation of Planets