WISPIT 2 revealed as a binary star system hosting two young protoplanets

Star system: TYC 5709-354-1 | Distance from the Sun: 437 light years

The WISPIT 2 system, known for harboring two giant protoplanets within a multi-ringed disc of gas and dust, has been identified as a spectroscopic binary. This means the system consists of two stars orbiting one another, visible through changes in their light patterns rather than direct imaging of both stars. This discovery establishes the system as a primary location for studying how planets form in environments around two stars.

The system consists of a primary Orange dwarf star with a mass roughly 97 percent that of the Sun and a secondary, smaller star at about 33 percent of the Sun's mass. The two stars complete an orbit around each other every 4.8 days, separated by a distance of approximately 0.072 astronomical units. One astronomical unit is the distance between Earth and the Sun.

To identify this binary nature, researchers used radial velocity measurements, which track the subtle shifts in a star's light caused by its gravitational interaction with a companion. They also analyzed specific light emissions to assess the accretion rate—the speed at which the stars pull in surrounding material. The measured rates were very low, suggesting that active planet-building material accumulation has largely ceased.

Key findings
- WISPIT 2 is the first circumbinary system observed to host directly imaged protoplanets.
- The central binary consists of a 0.97 solar mass primary star and a 0.33 solar mass secondary star.
- The stars orbit each other with a period of 4.8 days at a distance of 0.072 astronomical units.
- Low hydrogen-alpha emission indicates that active accretion of material onto the young stars is minimal.

Scientific study

A closer look at the WISPIT 2 host star. Evidence for a spectroscopic binary (external link)