Astronomers have made significant strides in understanding the formation of celestial bodies with the discovery of a massive planet and a brown dwarf orbiting distant stars. Utilizing the Subaru Telescope and the W.M. Keck Observatory on Mauna Kea, researchers have unveiled these two rare companions, marking the first results from the Observing Accelerators with SCExAO Imaging Survey (OASIS) program.
Thayne Currie, a professor at the University of Texas at San Antonio and principal investigator of OASIS, emphasized the importance of these findings. “These discoveries may help advance our abilities to image another Earth with future space-based observatories such as NASA’s Roman Space Telescope,” he stated. The combination of Mauna Kea’s superior observing conditions and advanced instrumentation has yielded remarkable results.
The first discovery, designated HIP 71618 B, is a brown dwarf with a mass equivalent to 60 times that of Jupiter, located approximately 169 light-years away in the constellation Bootes. Often referred to as “failed stars,” brown dwarfs form similarly to stars but do not accumulate sufficient mass for nuclear fusion. Consequently, they are cooler and far less visible in standard wavelengths, being more detectable in infrared light. The observations from the Keck/NIRC2 and Subaru/SCExAO instruments taken just days apart led to the identification of this companion. Additional data collected over the following year confirmed its orbital path.
The second notable find, HIP 54515 b, is an 18-Jupiter-mass planet orbiting a star 271 light-years away in the constellation Leo. This planet’s orbit is positioned at a distance from its star comparable to that of Neptune in our solar system. From Earth, it appears extraordinarily close to its host star, akin to the size of a football observed from over 320 kilometers away. The Subaru Telescope’s SCExAO system provided the high-resolution images necessary to detect this faint yet massive planet alongside its brighter star.
Upcoming Celestial Events and Observations
In addition to these discoveries, stargazers can look forward to the upcoming Quadrantids meteor shower, which will peak on the night of January 3 into January 4, 2024. Originating from the asteroid 2003 EH1, this meteor shower can produce up to 40 meteors per hour at its peak. With minimal moonlight interference expected this year, observers in Hawaii will be presented with favorable viewing conditions, especially after midnight when the radiant in Bootes rises higher in the sky.
January also brings the prominent star family Kekaomakali‘i, known as the “Bailer of Makali‘i,” which will dominate the night sky. This constellation, essential for traditional Hawaiian navigation, includes stars such as Hokulei (Capella) and Sirius (A‘a). As these stars rise high in the eastern sky after sunset, they serve as a celestial guide for voyagers across the Pacific.
Viewers can also spot bright planets throughout the month. Jupiter, known as Ka‘awela, will be visible shortly after sunset, while Hokuloa (Venus) will shine in the southwestern sky. For those equipped with binoculars or telescopes, these planets offer rewarding targets for stargazing enthusiasts.
For early risers, Jupiter will remain prominent in the pre-dawn western sky throughout January. Observers should also look toward Hokupa‘a in the north, where the Big Dipper can be spotted just before dawn, leading to Hokule‘a (Arcturus), a key star for navigation.
The discoveries from Mauna Kea not only enrich our understanding of planetary systems but also provide a glimpse into the wonders of the night sky. For more information about the OASIS program and its findings, visit the websites of the Keck Observatory and Subaru Telescope.
The ‘Imiloa Astronomy Center of Hawaii serves as a hub for informal science education, showcasing the intersection of astronomy and Hawaiian culture as part of humanity’s ongoing exploration of the universe.
