Skywatch: Astronomy news and happenings
W.M. Keck Observatory atop Maunakea and the University of Hawai‘i Institute for Astronomy’s Pan-STARRS on Haleakala teamed up to investigate a faint red star speeding across the galaxy.
First spotted by citizen science volunteers, the star was clocked moving through space at about 1.3 million miles per hour (600 kilometers per second). That is significantly faster than our own Sun, which is moving at about 220 kilometers per second.
According to Keck, the star may be on an unusual trajectory that could cause it to leave the Milky Way. This trajectory may be the result of two scenarios: the star was the companion to a white dwarf that went supernova, shooting its partner across the galaxy, or it was catapulted by binary black holes inside a globular cluster.
The star belongs to a category known as subdwarfs, which represent the oldest stars in the galaxy.
Special events
Fall Equinox: Sept. 22 marks the Autumnal, or Fall, Equinox when the Sun will rise exactly East and set exactly West. Despite the name “equinox,” this day will not actually have equal parts day time and night time.
For Hawai‘i, the date that comes closest to having equal amounts of day and night will be Sept. 28 when the day will last about 11 hours and 59 minutes. As we approach the winter season, the Sun will rise and set in the Southern sky and our days will be getting shorter.
Penumbral Lunar Eclipse: Hawai‘i will experience a penumbral lunar eclipse on the evening of Sept. 17. This occurs when the Moon, or a part of it, passes through the outer sections of the Earth’s shadow, known as the penumbra. Instead of turning red, as it would during a total lunar eclipse, the part of the Moon within the penumbra will take on a slightly darker color.
Penumbral lunar eclipses are hard to spot. The best time to try and catch it will be around the maximum eclipse. That will occur at about 6:25 p.m. in Hilo and 6:37 p.m. in Honolulu. The eclipse will end at 6:47 p.m.
Evening observing
Saturn (Makulu) will appear in the Southeastern sky, located within the Hawaiian star family, Kalupeakawelo.
Saturn is the most distant planet that we can see with the naked eye. Through a very good pair of binoculars, or through a telescope, observers can make out the planet’s ring system and Saturn’s largest moon, Titan.
To the West of Kalupeakawelo, the star family of Manaiakalani, The Fishhook of Maui, will stretch over the sky.
A triangle of stars in the North of Manaiakalani represents a coil of fishing line that belongs to the demigod, Maui.
The three stars in the North form the Navigator’s Triangle: Pira‘etea, (Deneb); Keoe (Vega); and Humu (Altair). Join the triangle in the North to Kamakaunuiamaui (Maui’s Fish Hook), Scorpius, in the South. The hook is baited and fishing for the giant trevally, Pimoe.
Morning observing
Early morning sky watchers can spot three planets: Saturn (Makulu), Jupiter (Ka‘awela), and Mars (Hoku‘ula).
Saturn, which is visible from dusk till dawn, will be leading these three planets in the Western sky. Jupiter will be trailing near the center of the sky adjacent to the Pleiades (Makali‘i) and the famous shape of Kaheiheianakeiki (Orion). Mars will complete this planetary lineup to the East of Saturn.
