Astronomers using the Subaru Telescope and the W.M. Keck Observatory on Mauna Kea have identified a significant new discovery: a massive planet and a brown dwarf orbiting distant stars. This breakthrough, part of the Observing Accelerators with SCExAO Imaging Survey (OASIS) program, enhances our understanding of the formation and evolution of giant planets and substellar objects.
The findings emerged from a large-scale survey combining precise stellar motion data from space-based missions with the advanced imaging capabilities of Mauna Kea’s observatories. According to Thayne Currie, a professor at the University of Texas at San Antonio and principal investigator of OASIS, “These discoveries may help advance our abilities to image another Earth with future space-based observatories such as NASA’s Roman Space Telescope.” Currie emphasized the benefits of Mauna Kea’s exceptional observing conditions, bolstered by state-of-the-art instrumentation.
The first notable discovery is HIP 71618 B, a brown dwarf with a mass approximately 60 times that of Jupiter, situated 169 light-years away in the constellation Bootes. Often described as “failed stars,” brown dwarfs form similarly to stars but do not possess enough mass to sustain nuclear fusion. They are cooler and fainter than stars, making them difficult to observe in visible wavelengths. The data collected from both the Keck Observatory and the Subaru Telescope over a short period enabled researchers to confirm the existence of this companion and reveal its orbit.
The second discovery, HIP 54515 b, is an 18-Jupiter-mass planet orbiting a star located 271 light-years away in the constellation Leo. This planet orbits at a distance comparable to Neptune’s orbit around our Sun and appears remarkably close to its host star when viewed from Earth, akin to a football seen from over 200 miles away. The Subaru Telescope’s SCExAO system provided the ultra-sharp images necessary to detect this faint giant planet alongside its brighter counterpart.
Upcoming Celestial Events
In addition to these discoveries, the astronomical community is anticipating the peak of the Quadrantids meteor shower, which will occur on the night of January 3 into the early morning of January 4, 2024. This shower, known for its bright meteors, can produce up to 40 meteors per hour at its peak. Observers in Hawaii will benefit from favorable viewing conditions, particularly after midnight when the radiant rises higher in the sky.
January also offers an opportunity to observe the star family Kekaomakali‘i, integral to traditional Hawaiian navigation. This starline, which includes notable stars like Hokulei (Capella), Na Mahoe (Gemini), and Kapuahi (Aldebaran), dominates the eastern sky after sunset. The presence of these stars serves as a celestial guide for voyagers across the Pacific.
During this period, Jupiter (known as Ka‘awela in Hawaiian) will be visible shortly after sunset, while the bright planet Hokuloa (Venus) will shine in the southwestern night sky. Stargazers equipped with binoculars or telescopes can enjoy the stunning views these planets offer.
For early risers, Jupiter will remain prominent in the pre-dawn western sky throughout January, providing a brilliant sight before sunrise. Observers can also spot the big dipper and trace its “panhandle” to find Hokule‘a (Arcturus), Hawaii’s zenith star.
The discoveries at Mauna Kea not only contribute to our astronomical knowledge but also highlight the intersection of traditional navigation and modern science. As researchers continue to explore the cosmos, the observations made through programs like OASIS pave the way for future advancements in our understanding of the universe.
For more information about the OASIS program, visit the following links:
– keckobservatory.org/accelerating-stars/
– subarutelescope.org/en/results/2025/12/03/3626.html
The ‘Imiloa Astronomy Center of Hawaii serves as a hub for informal science education, showcasing the rich connections between astronomy and Hawaiian culture.
