science

Scientists determine the origin of an object outside the sun, ‘Oumuamua’

Scientists determine the origin of an object outside the sun, 'Oumuamua'

This painting by William K. Hartman, Senior Scientist Emeritus at the Institute of Planetary Sciences in Tucson, Arizona, is based on a commission by Michael Pelton and shows the concept of an “Oumuamua being as a pie-shaped disk. Credit: William Hartman”

In 2017, the first interstellar object outside our solar system was discovered by the Pan-STARRS Astronomical Observatory in Hawaii. It was called “Oumuamua,” which means “scout” or “messenger” in Hawaii. The body was like a comet, but with features that were bizarre enough to defy the classification.


Two ASU astrophysicists, Stephen Desch and Alan Jackson from the College of Earth and Space Exploration, set out to explain the strange features of ‘Oumuamua’ and decide that it is likely a piece of Pluto-like planet from another solar system. Their findings were recently published in two papers in AGU The Journal of Geophysical Research: The Planets.

“In many ways, ‘Oumuamua was like a comet, but in many ways it was strange enough that mystery surrounded its nature, and speculation raged about what it was,” said Desh, a professor at the School of Earth and Space Exploration.

Of notes ThemeDesch and Jackson identified several characteristics of the body that differed from what would be expected of a comet.

In terms of speed, the object entered the Solar System at a slightly slower speed than expected, indicating that it has not traveled in interstellar space for more than a billion years or so. In terms of size, its flat shape was also flatter than any other known object in the solar system.

They also noted that while the object gained a slight thrust away from the sun (a “rocket effect” common in comets as sunlight evaporates the ice that forms them), the thrust was stronger than can be calculated. Finally, the body lacked detectable runaway gas, which is usually visualized by the comet’s tail. Overall, the object was very similar to a comet, but unlike any comet previously observed in the solar system.

Desch and Jackson then hypothesized that the object is made of different ice, and calculated how quickly this ice would sublimate (the transition from solid to gas) as Oumuamua passed by the sun. From there, they calculated the impact of the rocket, the mass and shape of the object, and the reflection of the ice.

Credit: Arizona State University

“That was an exciting moment for us,” said Desh. “We realized that a portion of the ice would be more reflective than people thought, which means it could be smaller. The effect of the missile itself would give ‘Oumuamua a greater boost, greater than what usually happens to comets.”

Desch and Jackson found one ice in particular – solid nitrogen – that provided a perfect match to all of the object’s features at once. Since solid nitrogen ice can be seen on Pluto’s surface, it is possible that a comet-like object was made of the same material.

Said Jackson, a research scientist and fellow exploration fellow at ASU. “This value appeared to be the same as what we observe on the surface of Pluto or Triton, which are bodies covered in nitrogen ice.”

They then calculated the rate at which bits of solid nitrogen ice could fall off the surfaces of Pluto and similar objects early in the history of our solar system. And they calculated the probability that bits of solid nitrogen ice from other solar systems would reach our array.

Jackson said, “It is possible that it was brought off the surface by a collision about half a billion years ago and thrown out of its original system.” “Being made of frozen nitrogen also explains the unusual shape of ‘Oumuamua. As the outer layers of nitrogen ice evaporated, the shape of the body was gradually becoming flattened, just as a bar of soap would do when the outer layers were rubbed through use.'”

Could Oumuamua be a strange technology?

Although the comet-like nature of ‘Oumuamua’ was quickly recognized, its inability to immediately explain it in detail led to speculation that it is a piece of space technology, as in the recently published book “Extraterrestrial: The First Signs of Intelligent Life Beyond Earth” Composed by Avi Loeb of Harvard University.

Scientists determine the origin of an object outside the sun, 'Oumuamua'

An illustration of a plausible history of “Oumuamua: the origin in its original system about 0.4 billion years ago; erosion by cosmic rays during its journey to the solar system; and its passage through the solar system, including its closest approach to the sun on September 9, 2017, and its discovery in October 2017.” At each point in its history, this illustration shows the projected size of “Oumuamua,” and the ratio between the longest and shortest dimensions. Credit: S. Selkirk / ASU

This sparked a public debate about the scientific method and scientists ’responsibility not to jump to unwarranted conclusions.

“Everyone is interested in aliens,” says Desh. “This first object outside the solar system was bound to make people think of aliens.” “But it is important in science not to jump to conclusions. It took two or three years to discover a natural explanation – a bit of nitrogen ice – that matches everything we know about Oumuamua. It’s not so long in science, it’s so far away and we quickly say we’re all exhausted. Natural Interpretations. “

Although there is no evidence that it is an alien technology, as part of a planet similar to Pluto, ‘Oumuamua has presented scientists with a special opportunity to look at extrasolar systems in a way that they have not been able to do before. As more objects like Oumuamua are found and studied, scientists can continue to broaden our understanding of what other planetary systems look like and the ways in which they are similar to or different from our solar system.

“This research is exciting because we may have solved the ‘Oumuamua puzzle, and we can reasonably define it as part of Pluto Exo, which is a Pluto-like planet in another solar system,” Dish said. “So far, we had no way of knowing if the systems were The other solar system has planets similar to Pluto, but we have now seen part of one of them pass close to Earth. ”

Desh and Jackson hope that future telescopes, such as the one at the Vera Rubin Observatory / Large Comprehensive Survey Telescope in Chile, which will be able to scan the entire southern sky on a regular basis, will be able to begin finding more interstellar objects. Other scientists could use it to further test their ideas.

“Hopefully, within a decade or so we will be able to have statistics about the kinds of things that are going through Solar SystemAnd if nitrogen glaciers were as rare or common as we thought, “Jackson said.” Either way, we should be able to learn a lot about other solar systems, and whether they have undergone the same types of collision history that did. ”


It is possible that Oumuamua came from a binary star system


more information:
Alan B. Jackson et al. 1I / ‘Oumuamua as a N2 icicle of the exo o Pluto surface: I. Size and compositional limitations, The Journal of Geophysical Research: The Planets (2021). Doi: 10.1029 / 2020JE006706

S. J Desch et al. 1I / ‘Oumuamua as an N2 icicle of the exo – pluto II surface: generation of N2 ice fragments and the origin of’ Oumuamua The Journal of Geophysical Research: The Planets (2021). Doi: 10.1029 / 2020JE006807

Introduction of
Arizona State University

the quote: Scientists identify the origin of the extrasolar body ‘Oumuamua (2021, March 17) Retrieved on March 17, 2021 from https://phys.org/news/2021-03-scientists-extra-solar-oumuamua.html

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