An article published in the journal “Nature Astronomy” reports a study on the protoplanet cataloged as AB Aurigae b, a gas giant that is growing following an unusual process called disk instability. A team of researchers used observations made with the Hubble Space Telescope and the Subaru Telescope on Mauna Kea, Hawaii, between 2007 and 2021 to find evidence of that violent formation. Proving that gas giants can form as a result of disk instability will help better understand the history of the solar system as well.

An article published in “The Astrophysical Journal” reports a study on the star system cataloged as HD 166191, which has an estimated age of 10 million years and is still in its formation process with objects that form but also get destroyed following collisions. A team of researchers led by Kate Su of the University of Arizona used data collected between 2015 and 2019 using NASA’s Spitzer Space Telescope and ground-based telescopes to detect traces of debris clouds generated by collisions between planetesimals. The information obtained from these data is very useful to improve our knowledge of the formation and evolution of planetary systems.

An article published in “The Astronomical Journal” reports a study that reviews the data of four objects discovered a few years ago thanks to NASA’s Kepler space telescope, concluding that at least three of them are actually tiny stars and not planets. A team of researchers used new data collected by ESA’s Gaia space probe to get more precise information on objects cataloged as exoplanets. Kepler-854b, Kepler-840b, and Kepler-699b appear to have sizes between two and four times Jupiter’s, too much even for hot Jupiters very close to their stars but possible for tiny stars. Kepler-747b turns out to have a radius 1.8 times Jupiter’s even though it’s quite far from a star a little smaller than the Sun, so its nature is uncertain.