AB Aurigae b

It may provide evidence for the formation of gas giant planets by disk instability. AB Aur b was discovered by a team led by Thayne Currie, Kellen Lawson, and Glenn Schneider using the Subaru Telescope on Mauna Kea, Hawaii and the Hubble Space Telescope (HST). The Subaru data utilized the observatory's extreme adaptive optics system, SCExAO, to correct for atmospheric blurring and the CHARIS integral field spectrograph to record AB Aur b's brightness measurements at different near-infrared wavelengths. AB Aur b's position coincides with the predicted location of a massive protoplanet required to explained CO gas spirals detected with ALMA and lies interior to the ring of pebble-sized dust seen in ALMA continuum data. The companion was initially detected in 2016: the team initially believed that the signal identified a piece of AB Aurigae's protoplanetary disk, not a newly forming planet. However, subsequent SCExAO/CHARIS data obtained with Subaru over the next four years showed that AB Aur b's spectrum is dissimilar to that of the protoplanetary disk, with a temperature similar to predicted values for a newly born planet. A new detection with HST using the STIS instrument and an archival detection with the now-decommissioned NICMOS instrument from 2007 confirmed evidence from Subaru data that AB Aur b orbits the star and is not a static feature. The planet's existence was disputed by two studies in 2023.