Skywatch: Rocky planet around white dwarf resembles Earth, 8B years from now
The discovery of an Earth-like planet 4,000 light years away in the Milky Way galaxy provides a preview of one possible fate for our planet billions of years in the future, when the sun has turned into a white dwarf, and a blasted and frozen Earth has migrated beyond the orbit of Mars.
This distant planetary system, identified by a University of California, Berkeley-led team of astronomers after observations with the W.M. Keck Observatory on Mauna Kea, looks very similar to expectations for the sun-Earth system: it consists of a white dwarf about half the mass of the sun and an Earth-size companion in an orbit twice as large as Earth’s today.
That is likely to be Earth’s fate. The sun will eventually inflate like a balloon larger than Earth’s orbit today, engulfing Mercury and Venus in the process. As the star expands to become a red giant, its decreasing mass will force planets to migrate to more distant orbits, offering Earth a slim opportunity to survive farther from the sun. Eventually, the outer layers of the red giant will be blown away to leave behind a dense white dwarf no larger than a planet, but with the mass of a star. If Earth has survived by then, it will probably end up in an orbit twice its current size.
For more information, visit keckobservatory.org.
Special events
During November, the star cluster of Makali‘i will rise in the quadrant of Ko‘olau at the exact same time that the sun sets. This is an important celestial indicator to begin the season of Makahiki. While this alignment is the major indicator of the start of the Makahiki season, a time of celebration and peace in traditional Hawaiian culture, there are many other indicators that Makahiki is beginning depending on who you ask. Other Makahiki markers include the arrival of the migratory Kolea birds and the first Hilo moon phase following the alignment of Makali‘i and the setting sun.
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Meteor shower
Through November, the spectacular Leonids meteor shower will scatter our sky with shooting stars. These meteors come from the tail of the comet Tempel-Tuttle, a periodic comet that last swept through Earth’s orbit in 1998. The peak of the shower will occur Nov. 16-17 when observers should see up to 10 meteors each hour.
Evening observing
Near the center of the sky will be Kalupeakawelo, also known as the Kite of Kawelo, which is one of the four great navigational starlines identified by the Polynesian Voyaging Society. At the center of this starline is the famous Great Square of Pegasus, which represents the body of a kite as it is being flown high overhead. North of the Great Square is the W shape of ‘Iwakeli‘i and the houselike shape of Kamo‘i. The starline also connects to some of the brightest stars in the southern fall sky. According to the legend, Kawelo was a Kauai chief and hero, most notable for the many athletic competitions in which he excelled. In a kite flying contest with his cousin, Kauahoa, Kawelo was able to twist, turn and make his kite leap, resulting in both kites becoming entangled and Kawelo’s kite severing the string of his cousin’s kite and carrying it away in the wind. Kawelo feared he would be punished by his much larger cousin, but Kauahoa blamed the wind. Those watching the competition interpreted the incident as a sign of Kawelo’s supernatural power.
Near Kalupeakawelo will be Makulu (Saturn). Saturn will be one of three planets visible in the evening sky. The other two are Ka‘awela (Jupiter) in the East and Hokuloa (Venus) near the Western horizon.
Morning observing
During November mornings, Ka‘awela (Jupiter) will stand out in the Western sky just before dawn. Behind Jupiter will be the Milky Way and the navigational star family Kekaomakali‘i, The Bailer of Makali‘i. Hoku‘ula (Mars) will trail Jupiter to the East.
November 2024 Sky Watch by Honolulu Star-Advertiser
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.