OASIS plays a key role in identifying the most promising candidates. The program examines precise data from two European Space Agency missions, Hipparcos and Gaia, searching for stars whose movements suggest the gravitational influence of unseen companions. Once these stars are pinpointed, OASIS uses the Subaru Coronagraphic Extreme Adaptive Optics (SCExAO) system to observe them, providing the exceptional precision and image quality needed to directly detect these hidden objects.

Figure 1. Giant Exoplanet 18 Times Jupiter’s Mass Spotted in Distant Star System.

A Massive Planet in Leo

The newly discovered planet, HIP 54515 b, orbits a star located 271 light-years away in the constellation Leo. Weighing nearly 18 times Jupiter’s mass, it orbits its star at a distance comparable to Neptune’s orbit around the Sun. Figure 1 shows Giant Exoplanet 18 Times Jupiter’s Mass Spotted in Distant Star System.

From Earth, the star and planet appear extremely close together—about the size a baseball would look from 100 km away. Thanks to the SCExAO system, astronomers obtained exceptionally sharp images, allowing the planet to be directly observed.

A Brown Dwarf in Bootes

The second discovery, HIP 71618 B, is a brown dwarf with 60 times the mass of Jupiter, situated 169 light-years away in the constellation Bootes. Brown dwarfs are often described as “failed stars” because they form like stars but never gain enough mass to sustain nuclear fusion.

A Crucial Target for NASA’s Roman Telescope

HIP 71618 B stands out for its suitability as a target for NASA’s Roman Space Telescope. Roman will conduct a technology demonstration to test coronagraph systems—tools that future telescopes will need to image Earth-like planets around other stars, which are roughly ten billion times fainter than their host stars.

Before this discovery, astronomers had no confirmed target meeting all the stringent requirements for this demonstration. HIP 71618 B changes that: its star is bright, and the brown dwarf is positioned just right. At the wavelengths the Roman Coronagraph operates, the brown dwarf will be faint enough relative to its star to effectively validate these new technologies.

These OASIS discoveries highlight the power of combining space-based precision star tracking with ground-based direct imaging. This collaborative approach uncovers planets and brown dwarfs that would otherwise remain hidden, demonstrating that the Subaru Telescope will remain a leading force in astronomy even as new observatories come online.

Source: SciTECHDaily

Cite this article:

Priyadharshini S (2025), Astronomers Discover Giant Exoplanet 18 Times the Mass of Jupiter in Distant Star System, AnaTechMaz, pp.632