Astronomers describe how they found a small planet forming • The Record

Astronomers have discovered a small planet hidden in clouds of gas and dust swirling within a young solar system, by studying the accumulation of material around Lagrangian points.

That’s according to research published this week in The Astrophysical Journal Letters.

Studying these protoplanets is difficult. Their star nurseries are shrouded in thick, hot lumps of mostly hydrogen gas, which prevents astronomers from clearly observing the birth of stars and planets.

“Direct detection of minor planets is very difficult and has so far only been successful in one or two cases,” said Feng Long, first author of the study and a postdoctoral fellow at Harvard’s Center for Astrophysics. “Planets are always so faint that we can’t see them because they are embedded in thick layers of gas and dust.”

To overcome this obstacle, Long and her colleagues developed a method for detecting children’s worlds, and used it to discover what appears to be a minor planet forming around LkCa 15, a small star located 518 light-years from Earth.

Here’s how the team said they did. They used observational data collected from the ALMA telescope, which revealed a mass of mass and an arc-shaped characteristic, both indications that something else was forming within the dense protoplanetary disk of matter surrounding the young star.

However, these images did not provide conclusive evidence of the formation of a planet around that sun. But another measurement linking the features convinced the team that they had found an alien world in the making. “This arc and clump are separated by about 120 degrees,” Long said. “This degree of separation doesn’t just happen – it’s computationally significant.”

The chapter showed that these two features lie in Lagrangian points, which are points in space around which objects can orbit steadily thanks to the gravitational force of two large nearby objects – for example, a star and a planet. NASA’s James Webb Space Telescope is located at Lagrangian Point II, or L2, in the solar system with Earth between it and the sun.

This means that the Webb telescope is effectively orbiting the point L2 due to the Sun and Earth being pulled over it. It remains, relatively speaking, the result of these two bodies. As NASA explains: “At Lagrangian points, the gravitational force of two large masses is precisely equal to the centripetal force needed to move a small body with them.”

The data from LkCa 15 showed that the arc is at point L4 and the clump is at L5. These objects are positioned because another body – a hidden planet – orbits between them; Lagrangian Points are the result of gravity by the young star and its forming world, just as the Sun and Earth form Lagrangian Points, one of which is home to the Webb probe.

Long and her colleagues used the data to simulate the growth of a planet with characteristics similar to those they thought they had found, and compared the results of their model with telescope images.

Strong similarities between simulations and observational data showed that a planet likely formed around LkCa 15. The mysterious object is estimated to be about the size of Neptune or Saturn, orbits the star at a great distance – 42 times the distance between the Sun and Earth, and is believed to be between one and three million years old. millions of years.

“[We] Long said: Put a planet in a disk full of gaseous parcels and dust particles, and watch how they interact and evolve under known physics. “Ultimately, an image is usually made to present the structure of the system in certain time steps. This model image will show what a millimeter wavelength emission would look like, [so we can] Make a direct comparison with our observations.”

In order for the simulations to be effective, astronomers had to gather as much information as possible about the new planets to enrich their modeling.

“There are one or two studies in the past that have attempted to predict associated planets with similar features, but in these examples, they only found one feature, so it’s not convincing,” Long said. record. “We found two, the block and the arc.”

“We are the first to detect mass accretion around the two Lagrangian points, so the location of the planet can be predicted more accurately. We look forward to applying this method to other systems,” she added.

She explained that the main thing in searching for developing planets is to search for empty gaps in the protoplanetary disk.

“Systems with known vacuoles are the main research targets,” Long told us. “This technique of finding minor planets actually has many unknown dependencies on other system properties that we are still exploring. [finding more] Samples with these features may be very useful in determining future research directions. “®

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