With the naked eye, the stars may all appear to be similar, and nothing more than pinholes in the sky, but the reality is that the stars come in a wide, almost stupefying range of sizes, masses, colors, compositions, and spectra. Needless to say, how bright a star appears to an observer is determined not only by the factors already mentioned, but also by its distance from Earth. Apparent magnitude is therefore the value assigned to a star’s brightness, and the brighter the object appears, the lower its value of magnitude. For instance, the Sun’s apparent magnitude is -27, the full Moon is -13, the brightest planet Venus is -5, while the brightest star on our list, Sirius, is -1.46. Absolute magnitude refers to how bright the star appears at a distance of 10 parsecs (32.6 light years).
• Constellation: Canis Major
• Right Ascension: 06h 45m 08.9s
• Declination: -16° 42′ 58″
• Apparent Mag: -1.46
• Absolute Mag: 1.4
• Distance: 8.6 light years.
• Spectral Type: Blue-white (A1Vm)
Also known as Alpha Canis Majoris, Dog Star, Canis Majoris, HD 48915, HR 2491, LHS 219, ADS 5423, LTT 2638, HIP 32349, among many others. The principal member of this three star system, Sirius A, has approximately twice the mass of the Sun, 25 times its luminosity, and at magnitude -1.42 is twice as bright as any other star visible in the night sky. It is also expected to increase considerably in luminosity as it approaches the solar system in the far distant future. The Sirius system, which is estimated to be less than 300 million years old, is visible from most of the earth’s surface except for far northern or southern latitudes. In favorable conditions, Sirius is also sometimes visible during daylight hours, and together with Betelgeuse, and Procyon in Canis Minor form an asterism of stars known as the Winter Triangle.
• Constellation: Carina
• Right Ascension: 06h 23m 57.1s
• Declination: -520 41’ 45”
• Apparent mag: -0.72
• Absolute mag: -2.5
• Distance: 74 light years
• Spectral Type: Yellowish-white (F0II)
Also known as Suhel, Suhail, Alpha Carinae, HR 2326, HD 45348. The origin of the name, “Canopus”, is not certain, but being the second most luminous star in the entire night sky, it is used a navigational beacon for spacecraft on inter-planetary journeys. Located in the constellation Carina, this yellow-white super giant is 14,800 times as luminous as the Sun, but is not visible from the northern hemisphere. At 316 light-years distant, Canopus is over 37 times as far away from the Earth as the number one star on our list, Sirius.
3) Alpha Centauri
• Constellation: Centaurus
• Right Ascension: 14h 39m 35.9s
• Declination: -600 50’ 07”
• Apparent mag: -0.27
• Absolute mag: 4.4
• Distance: 4.3 light years
• Spectral Type: Yellow-orange (G2V)
Also known as Rigil Kent, Toliman, Alpha 1 Centauri, HR 5459, HD 128620. Sometimes referred to as the “foot of the centaur”, this system of three stars consists of Alpha Centauri A, Alpha Centauri B, and Alpha Centauri C, with Alpha Centauri C being the closest star to earth, hence the name “Proxima Centauri”, that is sometimes used to refer to Alpha Centauri C. Compared to Earth’s Sun, Alpha Centauri A is around 1.5 times as bright.
• Constellation: Bootes
• Right Ascension: 14h 15m 39.7s
• Declination: +190 10’ 57”
• Apparent mag. : -0.04
• Absolute mag. : 0.2
• Distance: 34 light years
• Spectral Type: Orange (5IIIFe-0.5)
Also known as Haris-el-sema, Alpha Bootis, HR 5340, HD 124897. One of the closest giant stars to the Sun, Arcturus is an orange giant twice as massive and 100 times more bright than the Sun, making it the most luminous star in Bootes, one of the oldest recognized constellations. The name Arcturus means “bear guard”, or “watcher of the bear”, because of the way it seemingly looms over the constellation Ursa Major.
• Constellation: Lyra
• Right Ascension: 18h 36m 56.3s
• Declination: +380 47’ 01”
• Apparent mag: 0.03
• Absolute mag: 0.6
• Distance: 25 light years
• Spectral Type: Bluish-white (A0Va)
Also known as Wega, Fidis, Harp Star, Alpha Lyrae, HR 7001, HD 172167. Vega derives its name from the Arabic words for “swooping eagle”, and is a dwarf star three times as big, and 50 times as bright as the Sun. Along with Altair and Deneb, Vega forms a trio of stars popular called the Summer Triangle, which in the northern hemisphere announces the beginning of summer.
Right Ascension: 05h 16m 41.4s
Declination: +450 59’ 53”
Apparent mag: 0.08
Absolute mag: 0.4
Distance: 41 light years
Spectral Type: Yellow (G5IIIe+G0III)
Also known as Alhajoth, Alpha Aurigae, HR 1708, HD 34029. Capella, which is the Latin word for the term “little she-goat”, is one component of a multiple-star system, the brightest of which is a yellow giant, known as Aa, is of 2.466 solar masses, and 80 times as luminous as the Sun.
• Constellation: Orion
• Right Ascension: 05h 14m 32.3s
• Declination: -080 12’ 06”
• Apparent mag: 0.12
• Absolute mag: -8.1
• Distance: 1400 light years
• Spectral Type: Bluish-white (B8Ia)
Known as Rigel, Algebar, Elgebar, Beta Orionis, HR 1713, HD 34085. Deriving its name from the Arabic word for “foot”, Rigel marks the spot where in mythology a giant scorpion stung Orion after a fierce battle. Rigel is a multiple-star system, whose brightest star, the blue supergiant Rigel A, is of 17 solar masses and 40,000 times brighter than the Sun.
• Constellation: Canis Minor
• Right Ascension: 07h 39m 18.1s
• Declination: +050 13’ 30”
• Apparent mag: 0.38 (Visual binary system.)
• Absolute mag: 2.6
• Distance: 11.4 light years
• Spectral Type: Yellowish-white (F5IV-V)
Known as Procyon, Elgomaisa, Algomeysa, Antecanis, Alpha Canis Minoris, HR 2943, HD 61421. The name, Procyon, derives from the Greek phrase “before the dog”, referring to the fact that it rises before Sirius, the “Dog Star.” This yellow-white star is twice the size of our sun and seven times as luminous, but appears so bright because it is relatively close at 11.4 light-years.
• Constellation: Eridanus
• Right Ascension: 01h 37m 42.9s
• Declination: -570 14’ 12”
• Apparent mag: 0.46
• Absolute mag: -1.3
• Distance: 139 light years
• Spectral Type: Blue (B3Vpe)
Also known as Alpha Eridani, HR 472, HD 10144. Achernar derives its name from the Arabic phrase meaning “end of the river”, with the river in this instance being the constellation Eridanus. This blue-white supergiant star is seven times as massive as Earth’s Sun, and more than 3,000 times as luminous. It is almost tied with Betelgeuse on the number ten list, but is usually placed in 9th place as the luminosity of Betelgeuse is variable and ranges from 2,900 to 5,400 times that of our Sun.
• Constellation: Orion
• Right Ascension: 05h 55m 10.3s
• Declination: +070 24’ 25”
• Apparent mag: 0.50 (Variable.)
• Absolute mag: -7.2
• Distance: 1400 light years
• Spectral Type: Red (M1-2Ia-Iab)
Also known as Betelguex, Betelgeuze, Beteiguex, Al Mankib, Alpha Orionis, HR 2061, HD 39801. Rapidly evolving off the main sequence, Betelgeuse is now a bloated red supergiant with around 13,000 times the mass of the Sun, and just more than 10,000 times as luminous. If the Sun were replaced with Betelgeuse, the outer reaches of it would extend some distance past Jupiter’s orbit. Deriving its name from the Arabic word for “armpit”, this giant is located near Orion’s right shoulder. At some stage, Betelgeuse is expected to go supernova, and will then become the brightest star in the night sky temporarily, before fading and eventually becoming hard to see at all.