List of most luminous stars

Below is a list of stars arranged in order of decreasing luminosity (increasing bolometric magnitude). Accurate measurement of stellar luminosities is quite difficult in practice, even when the apparent magnitude is measured accurately, for three reasons:

1. The distance d to the star must be known, to convert apparent to absolute magnitude. Absolute magnitude is the apparent magnitude a star would have if it were 10 parsecs away from the viewer. Since apparent brightness decreases as the square of the distance (ie, as 1/d²), a small error (eg, 10%) in determining d implies an error ~2× as large (thus 20%) in luminosity. Stellar distances are only directly measured accurately out to d ~1000 lt-yrs.
2. The magnitudes at the wavelengths measured must be corrected for those not observed. "Absolute bolometric magnitude" (which term is redundant, practically speaking, since bolometric magnitudes are nearly always "absolute", i.e., corrected for distance) is a measure of the star's luminosity, summing over its emission at all wavelengths, and thus the total amount of energy radiated by a star every second. Bolometric magnitudes can only be estimated by correcting for unobserved portions of the spectrum that have to be modeled, which is always an issue, and often a large correction.
3. Even the observed magnitudes must be corrected for the absorption or extinction of intervening interstellar or circumstellar dust and gas. This correction can be enormous and difficult to determine precisely. For example, until accurate infrared observations became possible ~50 years ago, the Galactic Center region of The Milky Way was totally obscured to stellar observations, which had to be made in the optical.

This list also cannot be complete because if a star is far enough away, observers on Earth will not be able to see it, no matter how high its luminosity may be.

Because of all these problems, other references may give very different lists of the most luminous stars (different ordering or different stars altogether). Data on different stars can be of somewhat different reliability, depending on the attention one particular star has received as well as largely differing physical difficulties in analysis (see the Pistol Star for an example). The last stars in the list are familiar nearby stars put there for comparison, and not among the most luminous known. It may also interest the reader to know that The Sun is more luminous than approximately 95% of all known stars in the local neighborhood (out to, say, a few hundred light years), due to enormous numbers of somewhat less massive stars that are cooler and often much less luminous. For perspective, the overall range of stellar luminosities runs from dwarfs less than 1/10,000th as luminous as the Sun, to supergiants over 1,000,000 times more luminous.

Data

Star name	Apparent visible magnitude	Absolute bolometric magnitude	Bolometric luminosity (solar units)
R136a1 (in LMC)	12.77	−12.5[1]	8,700,000
Cygnus OB2-12	11.4	−12.2[2]	6,300,000
HD 93129A	6.97	−12.1	5,500,000[citation needed]
η Car	-0.8 to 7.9[3]	−12.0[4]	5,000,000[4]
LBV 1806-20 (Middle Model)	8.6	−12.0[5]	5,000,000[5]
QPM-241		−11.9	4,500,000
Pismis 24-1	10.43	−11.8	4,200,000
WR 101e	13.1	−11.6	3,700,000
WR 102ka		−11.6	3,700,000
HD 5980	11.52	−11.5	3,400,000
LSS 4067		−11.4[6]	3,000,000;
HD 93250	7.50	−11.3[6]	2,800,000;
Cygnus OB2-8	8.99	−11.3	2,750,000
Var 83 (in M33)	16.40	−11.1	2,240,000[7]
HDE 269810 (in LMC)	12.28	−11.1	2,200,000[8]
Wray 17-96	17.8	−10.9	1,800,000[9]
The Pistol Star (Low Model)		−10.8	1,700,000
ζ1 Sco	4.66 to 4.86	−10.8	1,700,000[10]
AF And (in M31)		−10.8	1,600,000[7]
LY Aurigae	6.85	−10.6	1,400,000
Tr 27-27		−10.5[6]	1,350,000;
Var B (in M33)		−10.4	1,100,000[7]
AG Car	5.7 to 9.0	−10.3	1,000,000[11]
S Dor	8.6 to 11.5 (B)	−10.1	870,000
Var C (in M33)		−9.8	660,000[7]
34 Cyg	4.8	−9.7	630,000
ρ Cas	4.1 to 6.2	−9.6	550,000
x Car	3.93	−9.5	520,000
HR Car		−9.5	500,000[12]
Plaskett's Star	6.05	−9.47	500,000 (high model)
DL Cru	6.24	−9.47	500,000
AE And (in M31)		−9.4	450,000[7]
VY CMa	6.5 to 9.6	−9.4	450,000[13]
χ2 Ori	4.65	−9.3	420,000
HDE 226868	8.9	−9.25	390,000
ε Ori	1.70	−9.2	380,000
KW Sgr	8.9	−9.17	370,000
ζ Pup	2.21	−9.0	360,000
V354 Cep	10.82 to 11.35	−9.15	360,000
RW Cep	6.52	−9.11	350,000
V509 Cas	5.10	−9.11	350,000
μ Cep (the Garnet Star)	4.04	−9.08	340,000
VV Cep A	4.91	−9.0	315,000
η CMa	2.45		300,000
ν Aql	4.69		300,000
WOH G64			280,000
KY Cyg		−8.84	270,000
θ1 Ori C	5.13	−8.6	220,000
6 Cas	5.55		200,000[14]
Betelgeuse	0.58		135,000[15][16]
ζ Ori	1.79	−7.8	100,000
VV Cep B		−7.8	100,000
The following well-known stars are provided for the purpose of comparison.
Rigel	0.12	−7.3	85,000
Antares	0.92	−7.2	66,000
Deneb	1.25	−6.95	54,000
Canopus	−0.62	−5.53	12,900
Achernar	0.46	−4.05	3,300[17]
β Lyrae	3.52	−3.91	2,900
Polaris	1.97	−3.6	2,200
Aldebaran	0.85	−0.63	350
Arcturus	−0.04	−0.31	210
Capella	0.08	0.4	78.5
Castor	1.98	0.5	50
Vega	0.00	0.58	37
Sirius	−1.46	1.4	25.4
α Centauri A	−0.01	4.38	1.519
Sun	−26.74	4.83	1.00

Note that even the most luminous stars are much less luminous than the more luminous persistent extragalactic objects, such as quasars. For example, 3C 273 has an average apparent magnitude of 12.8 (when observing with a telescope), but an absolute magnitude of −26.7. If this object were 10 parsecs away it would appear nearly as bright in the sky as our sun (apparent magnitude −26.74). This quasar's luminosity is, therefore, about 2 trillion (10¹²) times that of our sun, or about 100 times that of the total light of average large galaxies like our Milky Way. (Note that quasars often vary somewhat in luminosity.)

In terms of gamma rays, a magnetar (type of neutron star) called SGR 1806-20, had an extreme burst reach Earth on 27 December 2004. It was the brightest event known to have impacted this planet from an origin outside our solar system; if these gamma rays were visible, with an absolute magnitude of approx. −29, it would be brighter than our sun (as measured by the Swift spacecraft).

The Gamma-ray burst GRB 971214 measured in 1998 was at the time thought to be the most energetic event in the universe, with the equivalent energy of several hundred supernovae. Later studies pointed out that the energy was probably the energy of one supernova which had been "beamed" towards Earth by the geometry of the surrounding gas.

See also

• List of stars
• List of largest stars
• List of most massive stars
• List of brightest stars
• List of nearest stars
• Gamma ray burst
• Quasar

References

1. ^ SIMBAD Reference
2. ^ Thompson, Tim. "Cygnus OB2 #12 and the Cygnus OB2 Association". Tim Thompson's Home Page. http://www.tim-thompson.com/cyg-ob2-12.html. Retrieved 2009-10-25. 
3. ^ "GCVS Query=Eta+Car". General Catalogue of Variable Stars @ Sternberg Astronomical Institute, Moscow, Russia. http://www.sai.msu.su/gcvs/cgi-bin/search.cgi?search=Eta+Car. Retrieved 2010-11-24. 
4. ^ ^{a b} Humphreys, R. M. (May 23–28, 2004). "η Carinae -- The Observational Story, 1600 to 2004". In R. Humphreys and K. Stanek. The Fate of the Most Massive Stars, Proceedings of the conference. Grand Teton National Park, Wyoming: Astronomical Society of the Pacific. pp. 14–21. Bibcode 2005ASPC..332...14H. 
5. ^ ^{a b} Eikenberry, S. S.; et al. (November 2004). "Infrared Observations of the Candidate LBV 1806-20 and Nearby Cluster Stars". The Astrophysical Journal 616 (1): 506–518. arXiv:astro-ph/0404435. Bibcode 2004ApJ...616..506E. doi:10.1086/422180. 
6. ^ ^{a b c} Massey, Philip; DeGioia-Eastwood, Kathleen; Waterhouse, Elizabeth (2001). "The Progenitor Masses of Wolf-Rayet Stars and Luminous Blue Variables Determined from Cluster Turnoffs. II. Results from 12 Galactic Clusters and OB Associations". The Astronomical Journal 121 (2): 1050. arXiv:astro-ph/0010654. Bibcode 2001AJ....121.1050M. doi:10.1086/318769. 
7. ^ ^{a b c d e} Szeifert, T.; et al. (1996). "HST and groundbased observations of the `Hubble-Sandage' variables in M 31 and M 33". Astronomy and Astrophysics 314: 131–145. Bibcode 1996A&A...314..131S. 
8. ^ Walborn, Nolan R.; et al. (2004). "A CNO Dichotomy among O2 Giant Spectra in the Magellanic Clouds". The Astrophysical Journal 608 (2): 1028. arXiv:astro-ph/0403557. Bibcode 2004ApJ...608.1028W. doi:10.1086/420761. 
9. ^ Egan, Michael P.; et al. (2002). "An Infrared Ring Nebula around MSX5C G358.5391+00.1305: The True Nature of Suspected Planetary Nebula Wray 17-96 Determined via Direct Imaging and Spectroscopy". The Astrophysical Journal 572 (1): 288. Bibcode 2002ApJ...572..288E. doi:10.1086/340222. 
10. ^ Kaler, James B. (2001). Extreme stars: at the edge of creation. Cambridge: Cambridge University Press. p. 101. ISBN 0-521-40262-X. 
11. ^ Groh, J. H.; et al. (2006). "AG Carinae: A Luminous Blue Variable with a High Rotational Velocity". The Astrophysical Journal Letters 638 (1): L33. arXiv:astro-ph/0512372. Bibcode 2006ApJ...638L..33G. doi:10.1086/500928. 
12. ^ Machado, M. A. D.; et al. (2002). "HR Carinae: New spectroscopic data and physical parameters". Astronomy & Astrophysics 387 (1): 151–161. Bibcode 2002A&A...387..151M. doi:10.1051/0004-6361:20020295. 
13. ^ Humphreys, Roberta M. (2006). "VY Canis Majoris: The Astrophysical Basis of Its Luminosity". ePrint. arXiv:astro-ph/0610433. Bibcode 2006astro.ph.10433H. 
14. ^ Kaler, Jim (June 2, 2004). "6 Cassiopeiae". Star of the Week. http://www.astro.uiuc.edu/~kaler/sow/6cas.html. 
15. ^ Harper, Graham M.; et al. (2008). "A New VLA-Hipparcos Distance to Betelgeuse and its Implications". The Astronomical Journal 135 (4): 1430. Bibcode 2008AJ....135.1430H. doi:10.1088/0004-6256/135/4/1430. 
16. ^ Kaler, Jim (February 20, 1998). "Betelgeuse". Star of the Week. http://www.astro.uiuc.edu/~kaler/sow/betelgeuse.html. 
17. ^ Lovekin, C. C. (2006). "Surface Temperature and Synthetic Spectral Energy Distributions for Rotationally Deformed Stars". The Astrophysical Journal 643 (1): 460. arXiv:astro-ph/0602084. Bibcode 2006ApJ...643..460L. doi:10.1086/501492. 

External links

• The 150 Most Luminous Stars in the Hipparcos Catalogue
• About LBV 1806-20
• The Magnitude system
• About stellar magnitudes
• Tim Thompson's list of Brightest Star candidates