Astronomers at the Subaru Telescope and the W.M. Keck Observatory on Mauna Kea have made significant discoveries in the field of astronomy by identifying a massive planet and a brown dwarf orbiting distant stars. These findings, part of the Observing Accelerators with SCExAO Imaging Survey (OASIS) program, enhance our understanding of the formation and evolution of giant planets and substellar objects.
The discoveries mark a notable achievement for OASIS, a large-scale survey that integrates precise stellar motion data from space-based missions with the advanced imaging capabilities available at 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.” The combination of Mauna Kea’s exceptional observing conditions with state-of-the-art instrumentation has proven invaluable.
The first discovery, designated HIP 71618 B, is a brown dwarf with a mass approximately 60 times that of Jupiter, located 169 light-years away in the constellation Bootes. Often referred to as “failed stars,” brown dwarfs form similarly to stars but lack the requisite mass to sustain nuclear fusion. Consequently, they are cooler and significantly fainter in visible light than in infrared wavelengths, which are accessible through observations from the Keck Observatory and the Subaru Telescope. The companion was detected using data from both observatories, taken within days of each other, and follow-up observations confirmed its orbit.
In addition, the team discovered HIP 54515 b, an 18-Jupiter-mass planet orbiting a star 271 light-years away in the constellation Leo. Its orbit mirrors that of Neptune in relation to the Sun, although it appears extraordinarily close to its host star when viewed from Earth—similar to the size of a football seen from over 200 miles away. The Subaru Telescope’s SCExAO system provided the ultra-sharp images necessary to distinguish this faint giant planet from its brighter stellar neighbor.
Upcoming Astronomical Events and Cultural Significance
The astronomical community is also looking forward to the peak of the Quadrantids meteor shower, which will take place from 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. With minimal moonlight expected this year, observers in Hawaii should enjoy favorable viewing conditions, especially after midnight when the radiant point rises higher in the sky.
In January, the star family Kekaomakali‘i, meaning “Bailer of Makali‘i,” will dominate the night sky. Rising high in the eastern sky after sunset, this starline plays an essential role in traditional Hawaiian navigation. It includes stars such as Hokulei (Capella), Na Mahoe (Gemini), Kapuahi (Aldebaran), A‘a (Sirius), and Ke Ali‘i Kona i ka lewa (Canopus). The presence of Makali‘i (Pleiades) and the notable constellation ‘Iwakeli‘i (Cassiopeia) adds to the celestial richness visible this month.
For early risers, Jupiter (Ka‘awela) will be a brilliant sight in the pre-dawn western sky throughout January. Observers can also look for Hokupa‘a in the north and the distinctive “W” shape of the Big Dipper just before dawn. The bright cluster of stars serves as a reminder of the interconnectedness of the ocean and the stars, reinforcing the importance of navigation across the Pacific.
For further information about the OASIS program and its findings, interested individuals can visit the official websites of the Keck Observatory and the Subaru Telescope. The ‘Imiloa Astronomy Center of Hawaii, located at the University of Hawaii at Hilo, offers educational resources that showcase the intersection of astronomy and Hawaiian culture, highlighting them as parallel paths of exploration.
