Excessive towards the south this week at round 9:30 p.m. native time, we will see a “Nice Hexagon” of brilliant winter stars; a sample that was first conceived by writer Hans Augusto Rey (1898-1977) in his widespread sky information “The Stars — A New Way to See Them.”
Mr. Rey’s chief declare to fame was because the creator of the mischievous little monkey, Curious George. However he was additionally a really assiduous novice astronomer and each of his star guides (the opposite, a kids’s’ e book, “Find the Constellations”) are thought of enduring classics from the 1950s and have by no means been out of print since they have been first printed by Houghton Mifflin Co. of Boston.
A hexagon is a polygon with six sides and our celestial hexagon consists of six of the 21 brightest stars. To the south and a bit east lies the bluish star Sirius, in Canis Main, the “Canine Star,” the brightest of all stars. Sirius is roughly twice as large as our solar and shines 25 instances as luminous. However the chief purpose it seems so dazzling is that it lies comparatively near us; a distance of 8.6 light-years away. It seems to be stud on the Huge Canine’s collar.
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As much as the west is blue-white Rigel, within the constellation of Orion, the hunter. A supergiant star, situated 860 light-years from Earth and probably the most luminous of all of the naked-eye stars. It’s estimated to shine with a luminosity of roughly 120,000 instances that of our solar.
Nonetheless larger, is orange Aldebaran within the constellation of Taurus, the bull, an enormous star 65 light-years away, with the excellence of getting a planet estimated to be a number of instances extra large than Jupiter circling it. The bull is charging towards Orion and a V-shaped sample of stars represents his face — the Hyades star cluster — and we’d consider Aldebaran because the bull’s offended bloodshot eye,
Then on the north finish of the Hexagon we’d discover yellow Capella within the constellation of Auriga. At 42 light-years distant, that is really a quadruple star system composed of 4 stars. Capella is called the “she-goat star” and in the event you look fastidiously under and to its proper, you may see three a lot fainter stars popularly referred to as the “children,” or younger goats.
South and barely east, we come to yellow-orange Pollux, the brighter of the 2 stars marking the heads of the Gemini twins. Barely dimmer Castor is instantly adjoining to Pollux.
Lastly, south once more to Procyon, the “Little Canine Star” in Canis Minor. Like Sirius, it’s comparatively near us at solely 11.5 light-years away. Procyon is a Greek title that means “earlier than the canine.” And certainly, from mid-northern latitudes, it rises about 25 minutes previous to Sirius making its look above the east-southeast horizon.
There are two issues of curiosity that may be discovered inside the Hexagon. First is a really brilliant reddish star, Betelgeuse, a star that was within the information fairly a bit throughout 2020 as a result of it went by way of an sudden fading.
Since Betelgeuse is a crimson supergiant star and such stars are near the top of their life, there was some hypothesis that this star would possibly quickly finish its life in a supernova explosion. Nonetheless, scientists finally decided that the abnormal fading was more than likely attributable to an immense quantity of sizzling materials ejected into house, forming a mud cloud that briefly blocked starlight coming from Betelgeuse’s floor.
Additionally, contained in the Hexagon lies the intersection of the celestial and galactic equators. The celestial equator is just the aircraft of the Earth’s equator, projected on the sky. The galactic equator lies within the aircraft of rotation of the Milky Method. The 2 are inclined to one another at 62 levels. That worth, equivalent to the angular distinction between Earth’s axis and that of the galaxy, exhibits how far the Earth is tilted from the galactic viewpoint, and vice versa.
With so many brilliant stars encompassing a comparatively small area of the sky, it’s simple to check different geometrical shapes. In truth, earlier than Mr. Rey created his Nice Hexagon, he used Sirius, Procyon, Pollux, Castor and Capella to kind a sweeping semicircle which he known as the “Nice Arc of Sirius.”
And we will additionally kind a big, almost equilateral triangle fashioned by the celebrities Betelgeuse, Sirius and Procyon, generally known as the Winter Triangle. Just like the Vega-Deneb-Altair Summer Triangle, it overlaps the Milky Method, although a a lot much less conspicuous a part of it.
And but others have turned Rey’s Hexagon into one thing totally different: the heavenly “G.” Simply begin at Aldebaran and sweep counterclockwise down and round till you come to Rigel. Then, as an alternative of constant again to Aldebaran, divert as an alternative to Bellatrix, the star that marks Orion’s left shoulder; the third brightest star of the Orion constellation. Then head straight east (left) to Betelgeuse, finishing the define of the sixth letter of the alphabet.
Stars for all seasons
Orion, Taurus, Gemini and the opposite surrounding star patterns are conventionally known as winter constellations, but such seasonal designations are fairly free. They merely inform the season when a star sample is greatest seen throughout handy night hours.
Apart from the truth that these constellations are summertime ones for Australia and Brazil, they will also be seen in the course of the autumn by these within the Northern Hemisphere who might look skyward between midnight and daybreak. For instance, the identical stars and constellations that are actually within the sky in the course of the mid-evening hours might be seen at 5 a.m. native daylight saving time in mid-October.
Precession is one other issue that determines the “season” of a constellation. Precession refers back to the wobble of the Earth’s axis; a funnel-shaped movement, which describes one full wobble in about 25,800 years. At the moment, the star Polaris is the North Star. However again within the days of pyramids, some 5,000 years in the past — when the star Thuban was the North Star — Orion, Taurus and Gemini have been autumn constellations for the Northern Hemisphere. And when the good star Vega turns into the North Star in 14,000 AD, they are going to be summer season groupings.
Joe Rao serves as an teacher and visitor lecturer at New York’s Hayden Planetarium. He writes about astronomy for Pure Historical past journal, the Farmers’ Almanac and different publications. Observe us on Twitter @Spacedotcom and on Fb.