Astronomers Witness a Planet being Born, Challenging Formation Theories
By Rachel Kim, world-Today-News.com – September 26, 2025
In a groundbreaking discovery that’s rewriting our understanding of planet formation, astronomers have directly observed a protoplanet in the act of being born. The celestial body, designated AB Aurigae b, offers an unprecedented glimpse into the early stages of planetary progress, challenging long-held theories about how gas giants like Jupiter and saturn come into existence.
AB Aurigae b is a behemoth, approximately four times the mass of Jupiter, and resides a staggering 93 astronomical units from its parent star – roughly three times the distance between our sun and Neptune. What sets this protoplanet apart is that, unlike other young planets already settled into their orbits, AB Aurigae b remains deeply embedded within the dense gas and dust of its protoplanetary disk. This unique positioning allows scientists to witness its “growth” firsthand.
(Image: The protoplanet named AB Aurigae b has a mass of about four times that of Jupiter. (Photo/taken from ALMA)
An international team, led by the Japanese Center for Astrobiology, utilized the MUSE spectrometer at the European Southern Observatory in Chile to detect hydrogen alpha radiation emanating from AB Aurigae b. This radiation is a telltale sign of rapid gas accretion – the process by which the planet is actively pulling in mass.Remarkably, AB Aurigae b is only the second protoplanet ever confirmed using hydrogen alpha light, and the first to exhibit a distinct “anti-PCygni profile.”
This “anti-PCygni profile” is a specific spectral pattern indicating gas is falling onto the planet, rather than being ejected. Data reveals hydrogen spectral lines shifting both towards (blue shift) and away (red shift) from the observer at speeds of approximately 100 and 75 kilometers per second, respectively. This dual shift provides direct evidence of AB
