Astronomers at the Subaru Telescope and W.M. Keck Observatory on Mauna Kea, Hawaii, have identified two extraordinary celestial companions—an enormous planet and a brown dwarf. These findings enhance our comprehension of how giant planets and substellar objects develop and evolve in the universe. This research marks the initial results from the Observing Accelerators with SCExAO Imaging Survey (OASIS), a new large-scale program 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 the OASIS program, “These discoveries may help advance our abilities to image another Earth with future space-based observatories such as NASA’s Roman Space Telescope.” He emphasized the significance of combining Mauna Kea’s exceptional observing conditions with state-of-the-art instrumentation.
Significant Discoveries in Astronomy
The first companion identified, HIP 71618 B, is a brown dwarf with a mass equivalent to 60 Jupiter masses, located approximately 169 light-years away in the constellation Bootes. Often described as “failed stars,” brown dwarfs form in a similar manner to stars but lack the necessary mass to sustain nuclear fusion, resulting in their cooler and fainter characteristics. The observations from both the Keck/NIRC2 and Subaru/SCExAO, conducted within days of each other, allowed the astronomers to chart this companion’s orbit.
The second notable discovery is HIP 54515 b, an 18-Jupiter-mass planet orbiting a star situated 271 light-years away in the constellation Leo. Its orbit is comparable to that of Neptune around the Sun, although from Earth’s perspective, it appears remarkably close to its host star—similar to the apparent size of a football observed from over 200 miles away. The advanced imaging capabilities of the Subaru Telescope’s SCExAO system were crucial in capturing the sharp images necessary to detect this faint giant planet against the brightness of its star.
Upcoming Astronomical Events
Looking forward, the Quadrantids meteor shower, famous for its bright meteors, will reach its peak on the night of January 3 into the early morning of January 4, 2024. This meteor shower, which originates from the asteroid 2003 EH1, can produce as many as 40 meteors per hour at its height. This year, observers in Hawaii can anticipate excellent viewing conditions due to minimal moonlight interference, particularly after midnight when the radiant in Bootes ascends higher in the sky.
Throughout January, the star family Kekaomakali‘i, also known as the “Bailer of Makali‘i,” will take center stage in the night sky. This constellation, which includes stars such as Hokulei (Capella), Na Mahoe (Gemini), and Kapuahi (Aldebaran), plays a vital role in traditional Hawaiian navigation. As Makali‘i (the Pleiades) and Orion rise in the east, they remind voyagers of the celestial guidance that has long been integral to navigation across the Pacific.
For those interested in evening observing, Jupiter (known as Ka‘awela) will be visible shortly after sunset, while Hokuloa (Venus) will shine brightly in the southwestern sky. Observers equipped with binoculars or telescopes will find these planets rewarding targets for stargazing.
In the pre-dawn hours, Jupiter will continue to be a prominent feature in the western sky throughout January, beckoning early risers. Observers should look towards Hokupa‘a in the north to find the Big Dipper, and follow its “panhandle” to spot Hokule‘a (Arcturus), which is significant in Hawaiian culture as Hawaii’s zenith star.
The discoveries made by astronomers at Mauna Kea highlight not only advancements in astronomical research but also the cultural connections that the stars hold for various communities. For more information about the OASIS program and its findings, visit the websites of the Keck Observatory and the Subaru Telescope.
The ‘Imiloa Astronomy Center of Hawaii serves as a hub for informal science education, showcasing the intersections of astronomy and Hawaiian culture as parallel journeys of human exploration.
