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Hokupa’a, also known as Polaris or the North Star: We stare at it and use it as a tool to navigate through the world, but what do we know about the star? Or should we say, stars?
What we see in the night sky as one star is actually three: the yellow giant Polaris Aa, as well as the faint Polaris Ab and Polaris B. The smaller star was discovered by famed astronomer William Herschel in the late 1700s. Since then, Hokupa’a has continued to baffle astronomers and fascinate the public.
Now research from the Canada-France-Hawaii Telescope has revealed new details about Hokuba, shedding new light on one of the most famous stars in the sky.
Hokupa’a belongs to a class of stars known as classical cepheids. Crypt stars pulsate at a regular rate, varying in brightness over a specified period of time. They are so consistent that astronomers use cephalic measurements to measure distances to nearby galaxies.
Hokupa’a is an extraordinary cepid. While its brightness, temperature, and radius vary over a four-day period, Hokupa’a’s anisotropy also changes over a longer period of time.
The time between pulses increases by eight seconds per year. The star is now much brighter than it was in the past, perhaps 2.5 times brighter than it was in Greek antiquity, but differs to a lesser degree.
Enter James Barron, a graduate student at Queen’s University in Ontario, and his team. Baron has undertaken a project attempting to detect magnetic fields in classical Cepheid stars using the Canada-France-Hawaii Telescope.
CFHT is home to a highly specialized camera called ESPaDOnS, which takes light from a single star and splits it into the rainbow or spectra of the star, allowing astronomers to study the star’s properties.
ESPaDOnS is also used to measure the magnetic fields of stars, a unique ability. We see evidence of the Sun’s magnetic field in phenomena such as sunspots and solar flares. Baron discovered, for the first time, the magnetic field of Hokupa’a.
“I was analyzing the data obtained the night before, and was excited to see the magnetic field of Polaris. When I saw the results, I couldn’t believe my eyes! I actually checked with my thesis advisor that the results were real,” Barron said.
Hokupa’a’s magnetic field is very different from any other known vertical magnetic field. Barron and his team hope to solve this chicken-and-egg case — is the magnetic field different due to the star’s unique anisotropy, or is the unique variance caused by the magnetic field?
special events
>> Super Moon: On June 14, the full moon will occur when the moon is at perigee, which is the point of the moon’s orbit when it is at its closest to Earth. When the moon is full or near perigee, the moon appears slightly larger and brighter in the sky.
This event is often called a supermoon. Super pyramids can be up to 15% brighter than the average full moon.
Will you be able to tell the difference? Can! Like any astronomical event, the darker the location, the more likely it is to notice an increase in brightness. Regardless, full moon observations can be incredibly cool, especially here in Hawaii.
While the size of the moon is the same throughout the night, due to the optical illusion, it appears larger at moonrise. When the moon rises, we notice it moving through more air on the horizon than direct air on the horizon.
Also, when Kilauea erupts, the moon passes through a vog as it rises, just like the sun passes through a vog at sunset. This imparts a golden hue to the moon as it rises over the ocean.
With optical illusion of moonrise, super moon and golden color due to vog, this month’s full moon should look very elegant as it rises in the east.
>> Summer Solstice: June 21 marks the summer solstice in the northern hemisphere, the day when the Earth’s north pole is at its greatest tilt toward the sun.
This tilt of 23.5 degrees is responsible for Earth’s seasons and changes in the amount of day versus night we see throughout the year. On the summer solstice, the northern hemisphere experiences its longest day; Day length in Honolulu will be 13 hours and 25 minutes.
As one moves north, the sun sets later and later at the solstice. At the North Pole, the sun will set at 12:23 a.m. and rise at 2:59 a.m.
The summer solstice is an important event around the world. Many cultures celebrate the solstice, building monuments and developing rituals based on the longest day of the year. Likewise, traditions developed around the winter solstice, the longest night of the year.
Evening notes
The family of spring and summer Kaiwikuamo’o (the backbone) stars will stretch across the evening sky throughout the month of June.
To follow the full star family, start by locating the Nahiku (the Seven), also known as the Big Dipper, in the northeast. Draw a mental line between the two stars, Hikukahi and Hikulua, at the beginning of the Big Dipper’s “cup shape” northward to a faint star, Hokupa’a.
Return to the Big Dipper and follow the southern line from the Big Dipper’s handle to the Red Giant and the peak star of Hawaii, Hokule’a (Arcturus), the fourth brightest star in the night sky. Continue south and cross the celestial equator to Hekianalia (Spica) and to the trapezoidal constellation Mi (Corvus). Stretch a line through the center of Me’e toward the south and you’ll reach the cruciform constellation, Hanaiakamalama (Southern Cross).
In the southern sky, observers will be able to see some notable stars and celestial bodies.
Right next to Hanaiakamalama, we can see the two superstars Kamailehope (Alpha Centauri) and Kamailemua (Beta Centauri).
With our human eyes, these two stars seem to have the same brightness, but they are completely different from each other. Beta Centauri is a triple star system of bright stars 400 light-years away from us, which means it takes light 400 years to travel from the star system to Earth.
Alpha Centauri, also a three-star system of smaller and fainter stars, is the closest star system to our Sun at just 4 light-years away.
Not far from these outstanding stars, careful observers will also be able to see the misty light of a unique astronomical object, Omega Centauri.
To find the Omega Centauri, locate Hanaiakamalama. From the core of the cross, draw a line at an angle of 45 ° to the northeast; As you follow this line, you’ll see a misty smudge about 12 degrees north of Kamilemoa – this is Omega Centauri. Omega Centauri is a globular cluster containing about 10 million stars that orbits around the plane of the Milky Way.
morning notes
Early bird stargazers will enjoy a very different perspective of the night sky.
As summer approaches, the sun will rise earlier and the nights will get shorter: Throughout June, the sun will rise just before 6 a.m., and dawn will begin to color the sky starting at just 5:30.
Over the past few months, Venus, Jupiter, Mars, and Saturn have all been visible in the early morning sky, and observers have been watching as the planets dance along the eastern horizon. Early this morning, Jupiter and Mars were less than one degree apart from each other, concluding a series of planetary conjunctions that graced the morning sky.
While this is the last planetary conjunction in the near future, the early planets will remain.Morning sky with Venus and Jupiter, the brightest planets stand out amid dawn.
Starting from the second week of June, the five planets visible to the naked eye will be in the sky at the same time. Mercury, always the most difficult planet to identify, will reach its zenith over the northeast horizon just before dawn. Incredibly bright Venus will be above faint Mercury, while Mars, Jupiter and Saturn will create a gently curving line toward the southwestern sky.
Star chart for June 2022 by Honolulu Star-Advertiser
The Emilua Center for Hawaiian Astronomy is a center for informal science education at the University of Hawaii at Hilo, presenting astronomy and Hawaiian culture as parallel journeys of human exploration.