NASA’s Webb reveals hidden planet in Beta Pictoris system

Astronomers have confirmed the discovery of Beta Pictoris d, a giant gas planet that hid in plain sight for more than a decade, making it the faintest exoplanet ever directly imaged from Earth. NASA released the findings on Wednesday, July 15, describing the planet as a "hidden planet in a famous star system."science.nasa+1

A Decade-Long Game of Hide and Seek

Two independent teams detected the planet simultaneously using different instruments. Ben Sutlieff, Markus Bonse, and colleagues identified it in ground-based images from the European Southern Observatory's Very Large Telescope using the ERIS instrument, supported by archival data from JWST/NIRCam and VLT/SPHERE spanning 11 years. A second team led by Aidan Gibbs and Jean-Baptiste Ruffio found it in JWST/NIRSpec observations, marking the first time moderate-resolution spectroscopy has aided a direct-imaging exoplanet discovery.astrobiology+2

The planet had gone undetected because it frequently appeared too close to the glare of either the host star or the brighter planet Beta Pictoris b. Beta Pictoris d is estimated at roughly 2.4 times the mass of Jupiter, with an effective temperature of about 600 Kelvin and an orbital distance of approximately 26 AU from its star — the widest orbit of the system's three known planets. According to NASA, it is about 100 times fainter than its sibling planet Beta Pictoris b.futuretimeline+3

A Young System Comes Into Focus

Beta Pictoris, located 64 light-years away, is only 23 million years old and is surrounded by a vast debris disk of dust and planetesimals. The system already hosted two confirmed giant planets — Beta Pictoris b at about 10 AU and Beta Pictoris c at 2.7 AU. The discovery makes Beta Pictoris only the second directly imaged system known to contain more than two confirmed planets.futuretimeline

Early atmospheric analysis from Webb's NIRSpec instrument reveals signatures of methane, carbon monoxide, and water vapor, along with evidence of strong carbon dioxide absorption. These chemical clues position Beta Pictoris d as a key target for studying how young gas giants form and evolve, in a system that has been observed by astronomers since its debris disk was first spotted in 1984.futuretimeline