List of most massive stars
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This is a list of the most massive stars. The list is ordered by solar mass (1 solar mass = the mass of Earth's Sun).
Stellar mass is the most important attribute of a star. Combined with chemical compositions, mass determines a star’s luminosity, its physical size, and its ultimate fate. Due to their mass, most of the stars below will eventually go supernova or hypernova, and form black holes.
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[edit] Uncertainties and caveats
The masses listed in the table are inferred from theory, using difficult measurements of the stars’ temperatures and absolute brightnesses. All the listed masses are uncertain: both the theory and the measurements are pushing the limits of current knowledge and technology. Either measurement or theory, or both, could be incorrect. An example is VV Cephei, which, depending on which property of the star is examined, could be between 25 to 40, or 100 solar masses.
Massive stars are rare; astronomers must look very far from the Earth to find one. All the listed stars are many thousands of light years away, and that alone makes measurements difficult. In addition to being far away, it seems that most stars of such extreme mass are surrounded by clouds of outflowing gas; the surrounding gas obscures the already difficult-to-obtain measurements of the stars’ temperatures and brightnesses, and greatly complicates the issue of measuring their internal chemical compositions.
In addition, the clouds of gas obscure observations of whether the star is just one supermassive star, or instead a multiple star system. A number of the stars below may actually consist of two or more companions in close orbit, each star being massive in itself, but not necessary supermassive. Alternatively, it is possible for a multiple-star system to still have one (or more) supermassive star, with one (or more) much smaller companion(s). Without being able to see inside of the surrounding cloud, it's difficult to know which scenario might be the case.
Hence many of the masses listed below are contested, and being the subject of current research, are constantly being revised.
Amongst the most reliable listed masses are A1 and WR20a+b, which were obtained from orbital measurements. A1 and WR20a+b are both members of binary star systems (two stars orbiting around each other), and it is possible to measure in both cases the individual masses of the two stars by studying their orbital motion, via Kepler's laws of planetary motion. This involves measuring their radial velocities and also their light curves, as A1 and WR20a+b are both eclipsing binaries.
[edit] Stellar evolution
A number of the stars may have started out with even greater masses than those currently estimated, but due to the huge amount of gas they outflow, and sub-supernova and supernova imposter explosion events, have lost many tens of solar masses of material.
Also there are a number of supernovae and hypernovae remnants whose pre-cursor stars' masses can be estimated based on pre-super/hypernova observations, the energy of the super/hypernova, and the type of super/hypernova event. These stars (if they had not exploded) would have easily made appearances in this list (however they are not shown below).
[edit] List of the most massive stars
Known stars with an estimated mass of 20 or greater solar masses:
| Star name | Solar mass |
|---|---|
| Peony Nebula Star | 175 |
| HD 269810 | 150 |
| Eta Carinae | 150 |
| HD 93129A | 125 |
| The Pistol Star | 80-150 |
| LBV 1806-20 | 130-200 |
| HD 93129 A + B[1][2] | A=120, B=80 |
| HD 93250 | 118 |
| A1 in NGC 3603 | A=116, B=89 |
| Pismis 24-1 A + B[3][4] | A=100–120, B=100 |
| Arches cluster[5][6][7] | Many stars, 100–130 |
| Pismis 24-17[4] | 100 |
| S Doradus | 100 |
| Cygnus OB2-12 | 92 |
| WR20 a + b[8] | A=83, B=82 |
| Melnick 42[9][10][11] | 80–100 |
| HD 97950[12][13] | 80 |
| Sk-71 51[14] | 80 |
| R 66 | 70 |
| Companion to M33 X-7[15] | 70 |
| LH54-425 A + B[16] | A=62, B=37 |
| Var 83 in M33[17] | 60–85 |
| Sher 25 in NGC 3603[18] | 60 |
| Zeta-1 Scorpii[19] | 60 |
| Zeta Puppis[20] | 59 |
| WR22[21] | 55–74 |
| Plaskett A + B[22][23] | A=43, B=51 |
| AG Carinae | 50 |
| WR102c[24] | 45–55 |
| IRS-8*[25] | 44.5 |
| HD 5980 A + B[26][27][28] | A=40–62, B=30 |
| Epsilon Orionis | 40 |
| HD 148937[29][30] | 40 |
| IRAS 05423-7120[14] | 40 |
| Rho Cassiopeiae | 40 |
| Theta1 Orionis C | 40 |
| Xi Persei[31] | 40 |
| Companion to NGC300 X-1[32] | 38 |
| Cluster R136a | 12 stars, all 37–76 |
| Chi2 Orionis[33] | 35–40 |
| Companion to IC10 X-1[34] | 35 |
| VY Canis Majoris[35][36] | 30–40 |
| Gamma Velorum A | 30 |
| P Cygni | 30 |
| R 126 | 30 |
| Zeta Orionis | 28 |
| IRS 15[37] | 26 |
| VV Cephei | 25–40 |
| Alpha Camelopardalis[38][39] | 25–30 |
| 6 Cassiopeiae[40][41] | 25 |
| EZ Canis Majoris | 25 |
| KY Cygni[42] | 25 |
| Mu Cephei | 25 |
| V509 Cassiopeiae | 25 |
| NGC 7538 S[43] | 20–40 |
| Alpha Orionis (Betelgeuse) | 20 |
| S Monocerotis A[44] | 18–30 |
| WR47 | 8–48 |
[edit] Black holes
Black holes are the end point evolution of massive stars. Technically they are not stars, as they no longer generate nuclear fusion in their cores.
- Stellar black holes are objects with approx. 4–15 times the mass of our Sun.
- Intermediate-mass black holes range from 100-10000 times the mass of our Sun.
- Supermassive black holes are in the range of millions or billions of solar masses.
[edit] Eddington's size limit
Astronomers have long theorized that as a protostar grows to a size beyond 120 solar masses, something drastic must happen. Although the limit can be stretched for very early Population III stars, if any stars existed above 120 solar mass, they would challenge current theories of stellar evolution.
The limit on mass arises because stars of greater mass have a higher rate of core energy generation, which is higher far out of proportion to their greater mass. For a sufficiently massive star, the outward pressure of radiant energy generated by nuclear fusion in the star’s core exceeds the inward pull of its own gravity. This is called the Eddington limit. Beyond this limit, a star ought to push itself apart, or at least shed enough mass to reduce its internal energy generation to a lower, maintainable rate. In theory, a more massive star could not hold itself together, because of the mass loss resulting from the outflow of stellar material.
Studying the Arches cluster, which is the densest known cluster of stars in our galaxy, astronomers have confirmed that stars in that cluster do not occur any larger than about 150 solar masses.
[edit] See also
- Luminous blue variable
- Hypergiant
- List of least massive stars
- List of largest known stars
- List of most luminous stars
- List of brightest stars
- Lists of stars
[edit] External links
[edit] References
- ^ HD 93129A
- ^ Big and Giant Stars: HD 93129
- ^ HDE 319718 (Pis 24-1) and the Pismis 24 Cluster
- ^ a b http://spacespin.org/article.php/hubble-massive-star-system-pismis-24-1
- ^ Massive Stars in the Arches Cluster
- ^ Hubble Weighs In On The Heaviest Stars In The Galaxy
- ^ [0711.0657] The most massive stars in the Arches cluster
- ^ http://www.eso.org/public/outreach/press-rel/pr-2008/pr-37-08.html
- ^ http://www.nasa.gov/home/hqnews/1991/91-008.txt
- ^ Energy Citations Database (ECD) - - Document #5225537
- ^ Big and Giant Stars: Melnick 42
- ^ Big and Giant Stars: HD 97950
- ^ Quantitative spectroscopy of Wolf-Rayet stars in HD97950 and R136a - the cores o
- ^ a b The Blob, the Very Rare Massive Star and the Two Populations - Striking Image of Nebula N214C taken with ESO's NTT at La Silla | SpaceRef - Your Space Reference
- ^ NASA - Heaviest Stellar Black Hole Discovered in Nearby Galaxy
- ^ Big and Giant Stars: LH54-425
- ^ Big and Giant Stars: Var 83
- ^ Big and Giant Stars: Sher 25
- ^ http://www.astro.uiuc.edu/~kaler/sow/zeta1sco.html
- ^ http://www.astro.uiuc.edu/~kaler/sow/naos.html
- ^ http://adsabs.harvard.edu/full/1995LIACo..32..463R
- ^ Big and Giant Stars: Plaskett's Star
- ^ Plaskett's Star
- ^ http://www.astro.physik.uni-potsdam.de/abstracts/spitzer-andreas.html
- ^ Does IRS-8 contain the youngest and most massive star in the Galactic Center? | Gemini Observatory
- ^ Big and Giant Stars: HD 5980
- ^ ESA - Space Science - First X-ray detection of a colliding-wind binary beyond the Milky Way
- ^ http://www.esa.int/esaCP/SEMPYIO2UXE_index_0.html
- ^ http://www.gemini.edu/node/188
- ^ http://jumk.de/astronomie/big-stars/hd-148937.shtml
- ^ http://www.astro.uiuc.edu/~kaler/sow/menkib.html
- ^ http://arxiv.org/abs/0705.1544
- ^ http://www.astro.uiuc.edu/~kaler/sow/chi2ori.html
- ^ http://hera.ph1.uni-koeln.de/~heintzma/Spectra/WR_1.htm
- ^ http://www.daviddarling.info/encyclopedia/V/VY_Canis_Majoris.html
- ^ http://jumk.de/astronomie/big-stars/vy-canis-majoris.shtml
- ^ A Remnant Disk around a Young Massive Star
- ^ http://apod.nasa.gov/apod/ap061124.html
- ^ http://www.astro.uiuc.edu/~kaler/sow/alphacam.html
- ^ http://www.astro.uiuc.edu/~kaler/sow/6cas.html
- ^ http://jumk.de/astronomie/big-stars/6-cassiopeiae.shtml
- ^ http://jumk.de/astronomie/big-stars/ky-cygni.shtml
- ^ Witnessing the birth of a massive star
- ^ http://www.astro.uiuc.edu/~kaler/sow/15mon.html
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