The 26 Brightest Stars

Brightness Rank	Common Name	Scientific Name	Distance (light years)	m_v	M_v	Spectral Type	δ	Visible from Provo?
0	Sun		-	-26.72	4.8	G2V	-23½° to +23½°	yes
1	Sirius	Alpha CMa	8.6	-1.46	1.4	A1Vm	-17°	yes
2	Canopus	Alpha Car	74	-0.72	-2.5	A9II	-53°	no
3	Rigel Kentaurus	Alpha Cen	4.3	-0.27	4.4	G2V + K1V	-61°	no
4	Arcturus	Alpha Boo	34	-0.04	0.2	K1.5IIIp	19°	yes
5	Vega	Alpha Lyr	25	0.03	0.6	A0Va	39°	yes
6	Capella	Alpha Aur	41	0.08	0.4	G6III + G2III	46°	yes
7	Rigel	Beta Ori	~1400	0.12	-7.1	B81ae	-8°	yes
8	Procyon	Alpha CMi	11.4	0.38	2.6	F5IV-V	5°	yes
9	Achernar	Alpha Eri	69	0.46	-1.3	B3Vnp	-57°	no
10	Betelgeuse	Alpha Ori	~1400	0.50 (var.)	-7.2	M2Iab	7°	yes
11	Hadar	Beta Cen	320	0.61 (var.)	-4.4	B1III	-60°	no
12	Acrux	Alpha Cru	510	0.76	-4.6	B0.5Iv + B1Vn	-63°	no
13	Altair	Alpha Aql	16	0.77	2.3	A7Vn	9°	yes
14	Aldebaran	Alpha Tau	60	0.85 (var.)	-0.3	K5III	17°	yes
15	Antares	Alpha Sco	~520	0.96 (var.)	-5.2	M1.5Iab	-26°	yes
16	Spica	Alpha Vir	220	0.98 (var.)	-3.2	B1V	-11°	yes
17	Pollux	Beta Gem	40	1.14	0.7	K0IIIb	28°	yes
18	Fomalhaut	Alpha PsA	22	1.16	2.0	A3Va	-30°	barely
19	Becrux	Beta Cru	460	1.25 (var.)	-4.7	B0.5III	-60°	no
20	Deneb	Alpha Cyg	1500	1.25	-7.2	A2Ia	45°	yes
21	Regulus	Alpha Leo	69	1.35	-0.3	B7Vn	12°	yes
22	Adhara	Epsilon CMa	570	1.50	-4.8	B2II	-29°	barely
23	Castor	Alpha Gem	49	1.57	0.5	A1V + A2V	32°	yes
24	Gacrux	Gamma Cru	120	1.63 (var.)	-1.2	M3.5III	-57°	no
25	Shaula	Lambda Sco	330	1.63 (var.)	-3.5	B1.5IV	-37°	?

Magnitudes

The magnitude scale was invented by an ancient Greek astronomer named Hipparchus in about 150 B.C. He ranked the stars he could see in terms of their brightness, with 1 representing the brightest down to 6 representing the faintest. Modern astronomy has extended this system to stars brighter than Hipparchus' 1st magnitude stars and ones much, much fainter than 6.

As it turns out, the eye senses brightness logarithmically, so each increase in 5 magnitudes corresponds to a decrease in brightness by a factor 100. The absolute magnitude is the magnitude the stars would have if viewed from a distance of 10 parsecs or some 32.6 light years. Obviously, Deneb is intrinsically very bright to make this list from its greater distance. Rigel, of nearly the same absolute magnitude, but closer, stands even higher in the list. Note that most of these distances are really nearby, on a cosmic scale, and that they are generally uncertain by at least 20%. All stars are variable to some extent; those which are visibly variable are marked with a "v".

What are apparent and absolute magnitudes? Apparent is how bright the appear to us in the sky. The scale is somewhat arbitrary, as explained above, but a magnitude difference of 5 has been set to exactly a factor of 100 in intensity. Absolute magnitudes are how bright a star would appear from some standard distance, arbitrarily set as 10 parsecs or about 32.6 light years. Stars can be as bright as absolute magnitude -8 and as faint as absolute magnitude +16 or fainter. There are thus (a very few) stars more than 100 times more luminous than Sirius; most stars are much fainter.

Notice that northern skies are lacking in bright stars as compared with southern skies. Of the 24 stars other than the sun in the above list 14 are in the southern hemisphere, but only 10 are in the northern hemisphere. Even more striking-as seen from Provo about 12% of the sky is northern circumpolar (δ > 50°) and never sets while another 12% of the sky is southern circumpolar (δ < -50°) and never rises. Seven of the 24 bright stars are in the never-seen southern polar cap, but zero are in the always visible northern polar cap!

Stellar Brightness

The Brightest Stars, as Seen from the Earth

Magnitudes