Kathrine Frich
New orbital analyses suggest this binary star could support stable, Earth-like worlds that have gone undetected so far.
Humanity has always wondered where else life might exist in the universe.
Astronomers now sift through vast amounts of stellar data to determine which nearby systems could hold worlds worth examining more closely.
‘One candidate, Eta Cassiopeiae, seems unremarkable at first, yet researchers say it may hide promising locations for rocky planets.
Close and complex
Eta Cassiopeiae lies about 19 light-years from Earth. It is a binary system composed of a G-type star slightly heavier than the Sun and a lighter K-type companion with around 57 percent of the Sun’s mass.
The pair orbit a shared centre of gravity roughly every 472 years. No planets have yet been discovered there.
Researchers first examined precise measurements from the European Space Agency’s Gaia mission. They then added fresh high-resolution data from the Keck Observatory.
Together, these datasets allowed them to simulate how hypothetical planets would move around Eta Cassiopeiae A.
A key question was whether the companion star’s gravity would disrupt potential orbits.
Empty outer regions
The simulations showed that planets located beyond 8 astronomical units from the primary star would become unstable.
According to the models, such worlds would eventually be pushed out of the system entirely and drift through space as free-floating planets.
Researchers interpret this as evidence that the outer region around the star is likely empty of major planets.
Closer in, the picture changes. Simulated planets inside 8 AU remained in stable orbits despite the presence of the second star.
The system’s habitable zone, where temperatures might allow liquid water, appears unaffected by the binary partner.
Rocky worlds still possible
Astronomers note that any large gas giants within 8 AU would already have been identified through radial-velocity surveys.
Since no such detections exist, they argue the star is unlikely to host massive planets either near or far from its surface.
That leaves room for small, rocky, Earth-sized planets that current instruments cannot yet resolve.
The absence of giant planets could even improve the stability of such worlds, making the system a particularly intriguing target.
Sources: Wirtualna Polska, ESA, Keck Observatory
