Astronomers using the Gemini North telescope on Mauna Kea have made a fascinating discovery, identifying a group of transitional galaxies in the Virgo Cluster, which could unlock the mysteries behind ultracompact dwarf galaxies, or UCDs. UCDs are known to be among the densest stellar systems in the universe, but their origins have puzzled astronomers since their discovery more than two decades ago. The research, led by an international team, sheds light on the theory that UCDs are the remnants of disrupted dwarf galaxies.
Using deep imaging data from Gemini North, the team identified over 100 transitional galaxies that provide a glimpse into the evolutionary process of dwarf galaxies as they are torn apart and transformed into UCDs. This breakthrough research helps fill the gap between full-fledged galaxies and stellar clusters, advancing our understanding of how galaxies evolve over time.
Learn more about this research in the news release: noirlab.edu/public/news/noirlab2330.
Special events
>> December brings celestial wonders to Hawaii’s night skies, highlighted by the Geminids meteor shower. The Geminids, considered one of the best meteor showers of the year, will peak during the night of Dec. 13 and into the early morning hours of Dec. 14. During this time, stargazers can witness up to 120 meteors per hour. The Geminids are unique because they originate from the asteroid 3200 Phaethon, unlike most meteor showers, which are caused by comets. The meteors will be visible all across the sky but appear to radiate from the constellation Gemini. Best viewing will be after midnight in an area free of light pollution.
>> Additionally, on Dec. 21, the winter solstice will mark the shortest day and longest night of the year in the Northern Hemisphere. In Honolulu the sun will rise at 7:04 a.m. and set at 5:54 p.m., providing only 10 hours and 50 minutes of daylight. After the solstice the days will gradually become longer.
Evening observing
As the nights remain long in December, two significant Hawaiian star families illuminate the evening sky: Kalupeakawelo and Makali‘i.
Kalupeakawelo, also known as the “Kite of Kawelo,” will be prominently visible near the center of the sky during early evening. This starline, part of the four great navigational starlines of the Polynesian Voyaging Society, is marked by the Great Square of Pegasus, representing the body of the kite as it soars overhead. Surrounding the kite are the w-shaped constellation of ‘Iwakeli‘i (Cassiopeia) and the houselike Kamo‘i (Cepheus) to the north. According to legend, Kawelo, a Kauai chief and hero, demonstrated his supernatural prowess during a kite-flying contest that left onlookers amazed. Kalupeakawelo serves as a reminder of Kawelo’s ingenuity and the ancestral knowledge passed down through these stars.
Rising higher in the eastern sky is the Makali‘i star cluster (Pleiades), a brilliant collection of blue stars. This cluster is deeply tied to Hawaiian culture as a celestial indicator of the makahiki season, a time of peace, rest and harvest. The rising of Makali‘i, combined with natural markers such as the arrival of kolea birds and the Hilo moon phase, heralds this season of abundance and reflection. Observers can spot Makali‘i sparkling near the eastern horizon just after sunset, climbing steadily through the night.
For stargazers in December, these two star families offer a stunning display of Hawaiian celestial heritage. While Kalupeakawelo dominates the zenith in early evening, Makali‘i steadily ascends, providing a profound connection to the navigational brilliance of Hawaii’s ancestors.
Adding to the wonder of the December sky, both Saturn and Jupiter will shine brightly in the southern sky. While Saturn’s iconic rings can be viewed through a telescope, Jupiter — the brighter and closer of the two gas giants — will be easily visible to the naked eye. Stargazers with binoculars can spot Jupiter’s four largest moons — Io, Europa, Ganymede and Callisto — first observed by Galileo in 1610.
Morning observing
Before dawn, Hawaii’s early risers can observe the brilliant planet Hokuloa (Venus), known as the “Morning Star,” shining brightly in the east. Venus will remain the third-brightest object in the sky after the sun and moon throughout December, making it an easy and rewarding target for stargazers.
As December progresses, the Southern Cross (Hanaiakamalama) will return to the predawn sky, rising in the southeast about an hour before the sun. This constellation holds deep cultural significance, as it is associated with the celestial guidance used during voyages from the southern islands to Hawaii.
December 2024 Sky Watch[9] by Honolulu Star-Advertiser on Scribd
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The ‘Imiloa Astronomy Center of Hawaii is a center for informal science education at the University of Hawaii at Hilo showcasing astronomy and Hawaiian culture as parallel journeys of human exploration.
