Astronomers discovered stars posing as exoplanets

A team of researchers from the Massachusetts Institute of Technology (MIT) discovered that several objects that were previously thought to be exoplanets are actually small stars. This is presented in the article published in a recent issue of the Astronomical Journal.

Exoplanets in the artist’s view. Source: NASA

The objects in question are designated Kepler-854b, Kepler-840b and Kepler-699b. They were found using a transit method based on the detection of regular changes in the brightness of the star caused by the passage of invisible companions against the background of its disk. The advantage of this method lies in its obviousness and the possibility for further research of the body’s atmosphere (if any). The disadvantage is that it does not allow to determine the mass of the object, which makes it difficult to further classify it.

During one of the studies, astronomers from MIT discovered that the object previously considered the exoplanet is simply too big to be it. After that, they performed a full re-check of all known transit planets, then clarified the characteristics of their parent stars, and subsequently reassessed their radii.

The search was successful. Astronomers managed to detect several suspicious objects. So, it turned out that the radii of the exoplanets Kepler-854b, Kepler-840b and Kepler-699b are two to four times greater than the radius of Jupiter. This is very significant for exoplanets.

According to scientists, these objects are most likely small stars. Astronomers also managed to find another suspicious body, known under the designation Kepler-747b. Its radius is over 1.8 times the radius of Jupiter, which places it on the border between exoplanets and stars.

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