In its inaugural months, the James Webb Space Telescope (JWST) will target two planetary systems with young giant planets, aiming to unlock the mysteries of their formation.
Just days after its launch in late October, JWST will settle at the Sun-Earth Lagrange point L2, 1.5 million kilometers from Earth on the Sun's far side. Shielded by a 22-meter-long and 11-meter-wide sunshield of five ultra-reflective layers, it will peer into the early universe while studying exoplanets.
Astronomers worldwide recently submitted proposals, with select projects now approved for JWST's Cycle 1 observations.
These observations target massive planets unlike any in our Solar System, orbiting at vast distances from their stars. Free from intense stellar glare, these worlds may glow in infrared if sufficiently warm.
JWST's infrared sensitivity and coronagraph will enable direct imaging of these planets.
Prime targets include the 51 Eridani system, 96 light-years away, hosting a giant planet roughly twice Jupiter's mass at about 17 billion km from its Sun-like star. The HR 8799 system, 133 light-years distant, features four planets each at least ten times Jupiter's mass, orbiting over 22 billion km from a slightly more massive star.
Aged tens to hundreds of millions of years—compared to our 4.5-billion-year-old Solar System—these are "baby planets," still radiating heat.
A key goal is discerning formation mechanisms: Did they accrete from metal-rich protoplanetary disks like Jupiter, or collapse from hydrogen clouds like stars before gravitational contraction?
JWST's instruments, such as NIRCam, will analyze atmospheres for methane signatures, cloud properties, and temperatures.
Meanwhile, teams finalize the primary mirror deployment before shipping to French Guiana for launch on October 31 via Ariane 5.
