Using photometric data from NASA’s Kepler/K2 mission, astronomers have identified 747 unique planet candidates and 57 multiplanet systems; of these candidates, 366 have not been previously identified, including one multiplanet system and one system with two short-period gas giants.

An artist’s conception of the HR 858 planetary system. Image credit: Sci-News.com.

An artist’s conception of the HR 858 planetary system. Image credit: Sci-News.com.

“Discovering hundreds of new exoplanets is a significant accomplishment by itself, but what sets this work apart is how it will illuminate features of the exoplanet population as a whole,” said Professor Erik Petigura, an astronomer in the Department of Physics and Astronomy at the University of California, Los Angeles.

One challenge in identifying new planets is that reductions in staller brightness may originate from the instrument or from an alternative astrophysical source that mimics a planetary signature.

Teasing out which ones are which requires extra investigation, which traditionally has been extremely time consuming and can only be accomplished through visual inspection.

The planet detection algorithm developed by Professor Petigura and colleagues is able to separate which signals indicate planets and which are merely noise.

In the study, they analyzed the entire dataset from the Kepler/K2 mission — about 500 terabytes of data encompassing more than 800 million images of stars — to create a catalog that will soon be incorporated into NASA’s master exoplanet archive.

In addition to the 366 new planet candidates, the catalog lists 381 other planets that had been previously identified.

“The findings could be a significant step toward helping astronomers understand which types of stars are most likely to have planets orbiting them and what that indicates about the building blocks needed for successful planet formation,” said Dr. Jon Zink, a postdoctoral researcher in the Department of Physics and Astronomy at the University of California, Los Angeles.

“We need to look at a wide range of stars, not just ones like our Sun, to understand that.”

The discovery of the planetary system with two gas giant planets was also significant because it’s rare to find gas giants — like Saturn in our own Solar System — as close to their host star as they were in this case.

“We cannot yet explain why it occurred there, but that makes the finding especially useful because it could help scientists form a more accurate understanding of the parameters for how planets and planetary systems develop,” Dr. Zink said.

“The discovery of each new world provides a unique glimpse into the physics that play a role in planet formation.”

The team’s paper was published in the Astronomical Journal.

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Jon K. Zink et al. 2021. Scaling K2. IV. A Uniform Planet Sample for Campaigns 1-8 and 10-18. AJ 162, 259; doi: 10.3847/1538-3881/ac2309

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