BETELGEUSE
Big, band, bold, beautiful, brilliant, bloated Betelgeuse. If someone came up to us and said, "choose a favourite star or I'll smash all your Mannheim Steamroller Christmas CDs", we might just select this star as our main squeeze. What's not to love about a star that resembles a fire opal! Marking Orion's eastern shoulder, Betelgeuse is a red supergiant that could swallow more than 150 million Suns, if it developed a taste for unflavored plasma. While its translated name "giant's armpit" is hardly an endearing term, Betelgeuse is the mammoth sphere that puts a crimson flare in our crisp winter sky. It is about 520 light years away. It if were just a couple of hundred light years closer, it would be high on this bright star list! Even at its ranking now, though, Betelgeuse rocks.
HADAR
Let's pretend we're in the southern hemisphere during their early spring (our autumn). High in the evening sky one can see the magnificent Southern Cross, also known as 'Crux.' Just to the east of Crux is Beta Cenaturi (Hadar) and to the east of Hadar is Alpha Centauri (Rigil Kentaurus). The mnemonic is Alpha-Beta-Crux. Like its constellation companion Alpha Centauri, Hadar is among the brightest. However, at a distance of 390 light years, it is almost 100 times more distant than Alpha Centauri. Here we encounter one of the night sky's most effective deceptions: the concealment of depth. Alpha and Beta Centauri seem locked arm-in-arm, even though the former is poised on our shores, while the latter is far off on the horizon.
ALTAIR
Imagine a star that resembles a blue egg and you'll see Altair. The star marking the Summer Triangle's southern tip is one devil of spinner, as it rotates once every 8.9 hours, as opposed to the Sun's comparatively lethargic rotation rate (25 days at the Equator; 32 days at the poles.) Because Altair spins so rapidly, it bulges out dramatically at its equator, making it look like an egg. As it is a hotter star, it glows blue-white, hence the "blue egg" appearance. Altair, being so close at a distance of 16 light years, is one of the few stars that astronomers can directly image. These images have verified one of astronomy's somewhat more advanced theories, called the Von Zeipel effect. The Von Zeipel theorem states that a star's effective temperature is affected by its surface gravity. The stronger the gravity the higher the temperature: Altair's equator, being a bit farther out from the center than other regions, has a lower surface gravity and should be cooler, therefore slightly dimmer, since temperature and luminosity are related. And, indeed, this gravity darkening (Von Zeipel) effect has been observed on Altair.
ALDEBARAN
So, we admit it, we LOVE this star. Not only because of the enchanting Enya song of the same name, but because it is the follower star: the star that follows the Pleiades star cluster across the sky like an adoring lover. The name Aldebaran actually means "the follower" for this very reason. It marks Taurus the Bull's orange eye, the one glowering down at Orion, who has pursued the fleeing sisters with the same earnestness with which Aldebaran trails them. It's lovely to be admired, isn't it?
ANTARES
Rival to Mars! Well, that is what its name means. It is Mars' rival because of its red color. A star's temperature determines its color: Antares is red because it is a cool star, with an effective temperature of 2,300 degrees. Mind you, this temperature is blisteringly hot by planetary standards, but, as far as stars are concerned, is rather tepid. Antares marks the heart of Scorpius the Scorpion, a constellation currently lurking low in the pre-dawn sky.
SPICA
Remember the mnemonic "Arc to Arcturus?" It has a second verse. "Arc to Arcturus; Speed to Spica." Found south of Arcturus, Spica marks Virgo's hand. Spica has been corn, wheat, or another agricultural staple, for Virgo is the daughter of Demeter, goddess of the harvest. Finding Spica is handy as it is the one prominent star in the long and relatively faint constellation Virgo.
POLLUX
Pollux is the immortal Gemini twin and the constellation's brightest star. Mythologically, Pollux and Castor had the same mother, but different fathers. Pollux was sired by Zeus, the Greek god king. Having been Zeus' son, Pollux was immortal, while his brother Castor was not. When his brother was slain in battle, Pollux approached his father and offered to give his immortality to his Castor. So touched was Zeus by this gesture, that he offered both brothers a place in the sky where they could be together for all eternity. Pollux is the star south of Castor.
FOMALHAUT
We have something special to say about this "mouth" star. Marking the mouth of Piscis Austrinus, the "southern fish," Fomalhaut is not only noteworthy for being a bright star in our southern Autumn skies, but its planet was the first exo-planet ever directly observed. This planet is three times more massive than Jupiter and is almost three times farther away from Fomalhaut than Pluto is from the Sun. It is because the planet is so distant from its parent star, which is also close to us (25 light years) that it could be imaged with present day technology. We're likely to observe many other exo-worlds, but Fomalhaut's will always be the first ever "seen."
MIMOSA
The brightest star in the Southern Cross is not its alpha star. The Bayer system (see Gacrux) indicated that Mimosa was fainter than the cross' alpha star, Acrux. However, modern observations reveal that Mimosa (at magnitude 1.25) is slightly brighter than Acrux (magnitude 1.33). Astronomers use the magnitude system to measure the brightness levels of different celestial objects. The brighter the object, the lower the magnitude number. Mimosa and Acrux are so close in apparent brightness that the Bayer Nomenclature mistake is quite pardonable.
DENEB
Sometimes life isn't fair. Vega is much brighter and gets so much attention, but Deneb is far brighter than Vega when their actual luminosities are compared. Deneb is 60,000 times brighter than the Sun, because it is also 1600 light years away, so it seems dimmer than Vega, which is merely 26 light years distant. If Vega and Deneb traded places, Deneb would not only be the night sky's brightest star, but it would cast a shadow on us at night and would be visible during the day!
ACRUX
The "Southern Cross" is actually called Crux. This cross is famous because its longer axis points to the South Celestial Pole, a spot with a dirth of bright stars. (Sigma Octans marks the south celestial pole, but being barely visible, does not serve as a convenient marker.) While it is best to see the Southern Cross in the southern hemisphere, one can still observe it peeking above the southern horizon as far north as Florida. Yet, even here it is difficult to see.
REGULUS
The "Little King" representing Leo the Lion's heart. One can also see it as the point under Leo's sickle, "backward question mark." Like more than half of the night sky's stars, Regulus is a multiple system. Were one to visit Regulus, one would find four component stars. While binaries are somewhat common, quadruples are rare. When viewed telescopically, Regulus reveals three stars. One of these three is a spectroscopic binary, two stars so close together as to be optically unresolvable. Only by examining shifts in the stars' spectra are astronomers able to determine the presence of two stars.
ADHARA
Sometimes we don't know why stars have their given names. Adhara, the second brightest star in Canis Major, is the leg star in Orion's faithful hunting dogs. The name "Adhara" means "the virgins," as the three star triangle around Adhara was once called by the name "virgins." One can only speculate as to the origin of this name. During the many centuries that have elapsed between the days when stars were first given recorded names and our modern day, much knowledge has been lost and many legends forgotten. The appeal of Adhara is that this star's name is all that remains of these wholly unknown celestial virgins.
GACRUX
Here we have a moment to mention the Bayer Nomenclature System, which lists the stars within a constellation according to brightness. Developed by Johannes Bayer (1572-1625), this scheme assigns the Greek letter alpha to the constellation's brightest star; beta to the second brightest; gamma to the third brightest, and so forth. Gacrux is merely a contraction of the term Gamma Crux. Although, to be proper, Caesar, the actual star name must be formed by the Greek letter and the Latin genitive of the Host constellation name, so it would be Gamma Crucis. And, of course, everybody cares deeply about this issue.
SHAULA
"The Stinger Star" in the Scorpion's tail. Though listed as Lamba Scorpii, Shaula is Scorpius' second (not eleventh) brightest star. Shaula is called a "heat valve" star, more properly known as a Beta Cephei type variable. These variables expand and contract due to a layer of metals that behave like heat valves, causing fluctuations in heat transfer from the hotter inner regions. The magnitude difference during these variability periods, however, is slight, noticeable only with equipment much more sensitive than the human eye.
BELLATRIX
The Amazon Warrior star adorning Orion's western shoulder. While most know the name because of Bellatrix LaStrange, Harry Potter's truly wicked witch. Those who find this character to be appealing will have no trouble remembering that Bellatrix is special because it is one of the hottest stars visible to the naked eye. Its high "surface" temperature of 22,000 degrees makes it a truly bright star. A star's energy output, or luminosity, depends upon its size, mass and temperature. While Bellatrix is not a highly massive star, it is hot enough and close enough (250 light years) to place it neatly in the center of our top fifty list.
EL NATH
El Nath represents Taurus the Bull's horn tip. Taurus' beta star is far outshined by the alpha star Aldebaran. What distinguishes El Nath is that it is a lynch pin star, one that has been associated with another constellation. Some charts link El Nath with Auriga, the charioteer constellation to the north of Taurus and Orion. Very few prominent stars are shared by two constellations, however. Perhaps the most famous example is Alpheratz, the northeastern corner star in Pegasus that is actually considered part of Andromeda, the chained princess.
MIAPLACIDUS
Now, that is a name! Not that we're truly sure what it means. Those who study word origins believe the term derives from "gentle waters," as the star is in Carnina, the Keel. Years ago, a large ship adorned the southern skies. Called Argo Navis, this vessel was said to have conveyed the Argonauts in their quest for the Golden Fleece. This ship has been divided into four different constellations: Carina, Puppis, Vela and Pyxis.
ALNILAM
"The belt of pearls." The center star in Orion's belt doesn't garner the press coverage it deserves, perhaps because it is just one of Orion's belt trio: the three lovely sister stars Alnitak, Anilam, and Mintaka. Each Orion belt star is quite distant, but Alnilam is the farthest away (1340 light years). Despite its greater distance, Alnilam still appears brighter than its sisters because it is so intrinsically brilliant (370,000 times brighter than the Sun.) If Anilam were as close as Mintaka (915 light years), it would certainly rank higher than Orion's 4th brightest star.
AL NA'IR
This is the very first time the DA has mentioned the constellation Grus. Strangely, Grus represents a crane. The term Grus americana is the technical name for Whopping Crane. Once part of Piscis Austrinus, Grus was a creation of Petrus Plancius (1552-1622), who fashioned a dozen constellations out of faint stars. Only a few remain on the charts today. As it was once part of the southern fish, Al'Nair's name means "fish's tail," even though it now marks the crane's leg. For those of us around 43 degrees north latitude, Al Nair is just barely out of sight, visible only to those at or below 41 degrees north latitude.
ALIOTH
The curve in the Big Dipper's handle, or the handle star closest to the bowl. The three handle stars in the Dipper are Alioth, Alcor-Mizar, and Alkaid at the handle's end. Alcor-Mizar mark the handle's bend. Alioth is part of the Ursa Major Moving Cluster, an open star cluster at a distance of approximately 75 light years. Over thousands of years, the Big Dipper will dissipate as Alkaid and Dubhe, neither of which belong to this cluster, slowly migrate away from the others.
GAMMA VELUM
It is curious that a top 50 star has no proper name. (We'll encounter two examples of these.) Yet, no proper name has been recorded for this star. We must admit that the star names we have today derive from western civilization sources, which list precious few names for stars visible primarily in the southern hemisphere. Instead of a proper name, we have the star's Bayer Nomenclature Designation. (See Gacrux) So, Gamma Velum is the brightest star without a proper name.
MIRFAK
Perseus' brightest star is not its most famous star. Algol, the eclipsing binary representing Medusa's eye, is much better known. One can find Mirfak within the stick figure shape of Perseus. Astronomically, Mirfak is notable for being a supergiant (quite rare) and the brightest member of the 'Alpha Persei Cluster," an open cluster of stars only about 52 million years old. Open clusters are relatively young collections of gravitatioally bound stars. They are smaller and much younger than the other principal star cluster type, the globulars, which lurk in the halo, a spherical region centered on the galactic nucleus.
DUBHE
We like Dubhe because it is one of the "pointer stars," those two stars that direct us to the north star Polaris. Dubhe is the corner star in the Big Dipper's bowl. By drawing an imaginary line through the bowl's outer stars, Dubhe and Merak, one can find Polaris, which is about a dipper's length away.
WEZEN
The third brightest star in Canis Major, Wezen is one of the truly "young ones," being a star that formed about 10 million years ago. It has already ripped through its core hydrogen and is presently gathering enough heat to fuse helium. Like all massive stars, Wezen expends its nuclear fuel rapidly, unlike the Sun, which gradually burns through its fuel allotment over billions of years.
KAUS AUSTRALIS
Sagittarius is the archer aiming his arrow at Scorpius the Scorpion. Kaus Australis is that star in the arrow's tip. Star names are so fascinating because they derive from a variety of sources, such as Greek, Latin and Arabic. The name "Kaus Australis" means "bow of the south." One might recognize the Latin word "south" embedded in Australis. The southern lights are called the aurora australis. Remembering star names is an effective way of memorizing Latin, Greek, and Arabic direction and body part terms.
AVIOR
Some star names are quite ancient, dating as far back to the days of the Sumerians. Others are of much more recent vintage. The name "avior" was assigned to this star during World War II. The term refers to the pilots using the stars in their navigation. Being quite far south (not visible to those south of 28 degrees north latitude), it did not receive any proper name noted on any starchart. It is the brightest of the "ignored" stars.
ALKAID
The Big Dipper is well represented on this list. Alkaid is the end star in the Big Dipper's handle. It also represents the great bear's tail. It is curious that so many different cultures saw this pattern as a bear. Some native Americans referred to the dipper's bowl as the bear. The handle stars were three hunters pursuing the bear, with Alkaid taking up the rear. The name Alkaid has no relation to bears, however. The name means "the leader," for these stars were seen by Arab astronomers as the three daughters attending their father's funeral: the bowl being the tomb.
SARGAS
Sargas, marking the Scorpion's underbody, defines our southern horizon. As it lurks so close to the horizon, Sargas was used an indicator star: one whose visibility attested to clear southern sailing. Sargas is another star with a mysterious name, one most likely of Babylonian origin. Sargas is a Cepheid variable: a star that expands and contracts with a regular period. These stars are brilliant distance indicators since their variability period relates to their intrinsic brightness. By observing how much time a Cepheid requires to complete one variability cycle, one can measure its absolute brightness. Comparing this value to its apparent brightness yields its distance.
MENKALIMAN
Do you think Menkaliman is a strange name? Well, it's better than solstitial colure, a construct with which it is associated. What the devil is the "solstitial colure," you ask. It is the great circle that passes through both celestial poles and the two solstice points (Winter and Summer) You see, the Winter Solstice point is in Sagittarius; the Summer Solstice point is in Taurus. If you drew a circle between the North Celestial Pole and the South Celestial Pole so that it passes between both of these points, you'd draw the solstitial colure. Menkaliman, the second brightest star in Auriga the Charioteer, marks the solstitial colure's location, in much the same way that Polaris marks the North Celestial Pole's approximate position.
ATRIA
The sky is replete with triangles. One can make triangles almost everywhere. All one needs, after all, is a set of three stars. There are a couple official triangles in the sky: Triangulum and Triangulum Australe. (As we can guess, the latter one is the southern triangle) This triangle is WAY down there, ladies and gentlemen. It isn't even visible on the Tropic of Cancer. One has to be south of 20 degrees north to find it. Atria is so far south, it is one of the brightest stars close to the South Celestial Pole. Needless to say, we northern dwellers don't have a chance to find it.
ALHENA
Let's take a moment to explain the "Al," which is common in star names. Many stars were named by Arabic astronomers. These names often contain the prefix "al," the Arabic word for "the." Alhena is one such example. Even though it is Gemini's third brightest star, Alhena means "brand on the camel." Arabic astronomers did not see the Gemini stars as twins, but as a camel procession. One can find a great deal of incongruity between the names of constellations and the stars that comprise them. This is because we have a rich mish-mash of cultures that have left their imprints on the star charts.
PEACOCK
And, speaking of star names, how interesting it is to find a star name in English! The Peacock is the alpha star in Pavo, the Peacock. Another constellation that is far south of us, Pavo is a modern star pattern with an ancient association. Formed by Dutch explorers, Pavo represents Argos after Hera transformed him into a peacock after conveying his vessel the Argo Navis to the sky. As Pavo is near the four constellations made from the Argo Navis, its inclusion is quite logical, mythologically.
DELTA VELORUM
The other stars on the top 50 list that doesn't have a proper name. Delta Velorum is in Vela, part of Argo Navis. Those venturing into the southern hemisphere in search of the Southern Cross be warned: there is such a thing as the "false cross," an asterism within Vela. It resembles the southern cross as it consists of two perpendicular star lines. However, it is larger than Crux (the smallest constellation) and consists of fainter stars. Delta Velorum is in this false cross. Vela is the southern pole constellation on Mars, the star Kappa Velorum being only a couple degrees away from the Martian SCP.
MIRZAM
Canis Major's beta, but fourth brightest star. Yes, if you've been reading these little sections, you will remember that the Bayer system assigns Greek letters to a constellation's stars in order of relative brightness. However, the system is often inaccurate, as it was designed years before modern brightness determination equipment was invented. Like most of Canis Major's other bright stars, Mirzam is in the dog's head. Though it is much dimmer than Sirius, when Mirzam eventually explodes as a supernova, it will be as bright as a galaxy for a brief time and will outshine all the other stars. Of course, this fleeting fame will come at the cost of its life, but for some, being notorious is preferable to being extant.
CASTOR
The second brightest star in Gemini; also the name of the mortal twin. Castor is a six star system (two inner pairs of white stars around which revolve an outer red dwarf pair.) This star is a historical stepping stone, as it was the first place outside the solar system where astronomers could observe motion induced by gravity. As they determined that Castor's component stars moved in accordance to Newtonian laws, it helped us realize that gravity works all over the Universe.
ALPHARD The "solitary star." It occupies the region close to Regulus, but is the one prominent star in a dark part of the sky. Though it is low on our list, Alphard is still the brightest star in Hydra, the many-headed watersnake. Hydra, like Eridanus, is one of those meandering constellations consisting of relatively dim stars that, nevertheless, form a discernible procession across the heavens.
HAMAL
The brightest star in Aries the Ram. Whereas we've seen prominences on Betelgeuse, we've observed a phenomenon called "limb darkening" on Hamal. Limb darkening is the apparent darkening visible along the limbs (outer edges) of the Sun. We perceive such darkeneing because when we observe the sun's outer edges, we're peering through a thicker section of gases than we see in the Sun's center. Thus, the solar limbs seem "shadowed" As Hamal is a close star (15 light years), similar edge diminishment is also observable.
NUNKI
Have you ever heard of the "Little Milk Dipper?" Well, let us tell you that it is one the night sky's hidden gems. Like the Big Dipper, the Little Milk Dipper is an asterism (a star pattern contained within a larger constellation.) This Little Milk Dipper is part of Sagittarius the Archer. Sagittarius is steeped in the Milky Way Galaxy's glow, as the constellation is aligned with the region marking the galaxy's center. In this part of the sky field we encounter wide swaths of brilliant star light. The Little Milk Dipper is a five star asterism that appears upside down to us, as though it were pouring milk out onto the shimmering stars below it. This dipper encompasses Sagittarius' northern portion. Nunki is the northern star in this asterism.
POLARIS
Yes, you have to wait until you reach the list's bottom to finally encounter Polaris, the north star. As it has the name recognition that most other stars do not enjoy, people naturally assume it's the brightest. However, it barely makes the top 50. Polaris is currently the north star because Earth's northern axis is aligned close to it. The star barely appears to move during the night and always marks north. Eventually, precession (Earth's wobble) will shift Polaris away from his position, allowing for other stars to eventually become the north star. In fact, Vega will become the north star 13,000 years from now.
DENEB KAITOS
The Whale's Tail is the tail end of today's DA Deneb Kaitos, also known as Diphda, marks the tail of Cetus the Whale (or sea monster) Cetus was the monster released by Posideon to destroy Cassiopeia's village after the latter insulted the former by declaring that the latter's daughter was more beautiful than the former's sea nymphs. It's an ancient story that needn't be rehashed here. Suffice it to say that all ended happily for everyone, except Cetus. Take note of the word "deneb," meaning tail. We see that a few times in star names, such as Deneb, the tail of Cygnus the Swan and Denebola, the Lion's tail.