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Jeans instability

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gas, the adiabatic index is 5/3. However, in astrophysical objects this value is usually close to 1 (for example, in partially ionized gas at temperatures low compared to the ionization energy). More generally, the process is not really adiabatic but involves cooling by radiation that is much faster than the contraction, so that the process can be modeled by an adiabatic index as low as 1 (which corresponds to the polytropic index of an isothermal gas). So the second case is the rule rather than an exception in stars. This is the reason why stars usually form in clusters.
187: 1640: 4724: 4736: 1393: 3244:; i.e., the cloud's radius is the Jeans' length when thermal energy per particle equals gravitational work per particle. At this critical length the cloud neither expands nor contracts. It is only when thermal energy is not equal to gravitational work that the cloud either expands and cools or contracts and warms, a process that continues until equilibrium is reached. 1282: 4748: 4675: 797: 42: 1635:{\displaystyle M_{\text{J}}={\frac {4\pi }{3}}\rho R_{\text{J}}^{3}={\frac {\pi }{6}}\cdot {\frac {c_{\text{s}}^{3}}{G^{\frac {3}{2}}\rho ^{\frac {1}{2}}}}\approx 2{\text{ M}}_{\odot }\cdot \left({\frac {c_{\text{s}}}{0.2{\text{ km/s}}}}\right)^{3}\left({\frac {n}{10^{3}{\text{ cm}}^{-3}}}\right)^{-{\frac {1}{2}}}.} 1114: 940: 4023:
the Jeans mass decreases with increasing density. During gravitational collapse density always increases, thus in the second case the Jeans mass will decrease during collapse, allowing smaller overdense regions to collapse, leading to fragmentation of the giant molecular cloud. For an ideal monatomic
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An alternative, arguably even simpler, derivation can be found using energy considerations. In the interstellar cloud, two opposing forces are at work. The gas pressure, caused by the thermal movement of the atoms or molecules comprising the cloud, tries to make the cloud expand, whereas gravitation
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is appropriate for molecular hydrogen with 20% helium by number). When the sound-crossing time is less than the free-fall time, pressure forces temporarily overcome gravity, and the system returns to a stable equilibrium. However, when the free-fall time is less than the sound-crossing time, gravity
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two possible scenarios. An exactly homogeneous distribution has no clear center of mass and no clear way to define a gravitational acceleration direction. For the other case, Jeans extends what Newton wrote about: Jeans demonstrated that small deviations from exact homogeneity lead to instabilities.
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considered a universe without edges and pondered what would happen if the "system of the world", which exists within the universe, were finite or infinite. In the finite case, stars would gravitate towards the center, and if infinite, all the stars would be nearly in equilibrium and the stars would
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It was later pointed out by other astrophysicists including Binney and Tremaine that the original analysis used by Jeans was flawed: in his formal analysis, although Jeans assumed that the collapsing region of the cloud was surrounded by an infinite, static medium, the surrounding medium should in
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James Jeans extended the issue of gravitational stability to include pressure. In 1902, Jeans wrote, similarly to Halley, that a finite distribution of matter, assuming pressure does not prevent it, will collapse gravitationally towards its center. For an infinite distribution of matter, there are
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is the radius. The equilibrium is stable if small perturbations are damped and unstable if they are amplified. In general, the cloud is unstable if it is either very massive at a given temperature or very cool at a given mass; under these circumstances, the gas pressure gradient cannot overcome
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Jeans instability can also give rise to fragmentation in certain conditions. To derive the condition for fragmentation an adiabatic process is assumed in an ideal gas and also a polytropic equation of state is taken. The derivation is shown below through a dimensional analysis:
591:. The cloud is stable for sufficiently small mass (at a given temperature and radius), but once this critical mass is exceeded, it will begin a process of runaway contraction until some other force can impede the collapse. He derived a formula for calculating this critical 3388: 679: 1653:
Remarkably, when using a more careful analysis taking into account other factors such as the expansion of the Universe fortuitously cancel out the apparent error in Jeans' analysis, and Jeans' equation is correct, even if its derivation might have been dubious.
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is the critical radius of a cloud (typically a cloud of interstellar molecular gas and dust) where thermal energy, which causes the cloud to expand, is counteracted by gravity, which causes the cloud to collapse. It is named after the British astronomer
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reality also be collapsing, since all larger scales are also gravitationally unstable by the same analysis. The influence of this medium was completely ignored in Jeans' analysis. This flaw has come to be known as the "Jeans swindle".
2717: 3550: 1277:{\displaystyle \lambda _{\text{J}}={\frac {c_{\text{s}}}{(G\rho )^{\frac {1}{2}}}}\approx 0.4{\text{ pc}}\cdot {\frac {c_{\text{s}}}{0.2{\text{ km/s}}}}\cdot \left({\frac {n}{10^{3}{\text{ cm}}^{-3}}}\right)^{-{\frac {1}{2}}}.} 368: 2382: 3748: 3290: 3755: 799:
for sound waves to cross the region and attempt to push back and re-establish the system in pressure balance. At the same time, gravity will attempt to contract the system even further, and will do so on a
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the mass of a particle comprising the gas. Assuming the cloud to consist of atomic hydrogen, the prefactor can be calculated. If we take the solar mass as the unit of mass, and use units of
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within a gaseous cloud. He was able to show that, under appropriate conditions, a cloud, or part of one, would become unstable and begin to collapse when it lacked sufficient gaseous
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tries to make the cloud collapse. The Jeans mass is the critical mass where both forces are in equilibrium with each other. In the following derivation numerical constants (such as
792:{\displaystyle t_{\text{sound}}={\frac {R}{c_{\text{s}}}}\approx 0.5{\text{ Myr}}\cdot {\frac {R}{0.1{\text{ pc}}}}\cdot \left({\frac {c_{\text{s}}}{0.2{\text{ km/s}}}}\right)^{-1}} 2013: 3242: 1286:
This length scale is known as the Jeans length. All scales larger than the Jeans length are unstable to gravitational collapse, whereas smaller scales are stable. The Jeans mass
3192: 2636: 1109: 1928: 404: 3423: 3285: 2854: 2553: 2310: 1338: 1311: 1014: 674: 4596: 3879: 453: 277: 3475: 3043: 2631: 2317: 935:{\displaystyle t_{\text{ff}}={\frac {1}{(G\rho )^{\frac {1}{2}}}}\approx 2{\text{ Myr}}\cdot \left({\frac {n}{10^{3}{\text{ cm}}^{-3}}}\right)^{-{\frac {1}{2}}},} 3447: 3008: 2988: 2942: 980: 2898: 2064: 1876: 1737: 1681: 1847: 3671:{\displaystyle PV=nRT\Rightarrow P\cdot P^{-{\frac {1}{\gamma }}}=P^{\frac {\gamma -1}{\gamma }}\propto T\Rightarrow P\propto T^{\frac {\gamma }{\gamma -1}}.} 2965: 3156: 2918: 2878: 2601: 2577: 2271: 2251: 2231: 2084: 2035: 1970: 1950: 1821: 1801: 1781: 1761: 1708: 960: 644: 624: 517: 493: 473: 424: 552:, wrote that it's hard to imagine that particles in an infinite space should be able to stand in such a configuration to result in a perfect equilibrium. 2521:{\displaystyle M_{\text{J}}=\left({\frac {375k_{\text{B}}^{3}}{4\pi m^{4}G^{3}}}\right)^{\frac {1}{2}}\left({\frac {T^{3}}{n}}\right)^{\frac {1}{2}},} 603:. The greater the mass of the cloud, the bigger its size, and the colder its temperature, the less stable it will be against gravitational collapse. 168: 606:
The approximate value of the Jeans mass may be derived through a simple physical argument. One begins with a spherical gaseous region of radius
3689: 4564: 4402: 4316: 3868:{\displaystyle M_{\text{J}}\propto T^{\frac {3}{2}}\rho ^{-{\frac {1}{2}}}\propto \rho ^{{\frac {3}{2}}(\gamma -1)}\rho ^{-{\frac {1}{2}}}.} 4784: 4589: 1042: 2151: 4774: 4541: 4237: 2089: 230: 208: 3383:{\displaystyle \lambda _{\text{J}}={\frac {2\pi }{k_{\text{J}}}}=c_{\text{s}}\left({\frac {\pi }{G\rho }}\right)^{\frac {1}{2}},} 1343: 4699: 132: 4582: 2947:
Perhaps the easiest way to conceptualize Jeans' length is in terms of a close approximation, in which we discard the factors
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is released. When this energy equals the amount of work to be done on the gas, the critical mass is attained. Let
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The critical mass is attained as soon as the released gravitational energy is equal to the work done on the gas:
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is not strong enough to prevent the gravitational collapse of a region filled with matter. It is named after
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Abbasi, Amir (2018). "Effect of polarization force on the Jeans instability in collisional dusty plasmas".
3993: 3960: 2822:{\displaystyle \lambda _{\text{J}}=\left({\frac {15k_{\text{B}}T}{4\pi G\mu \rho }}\right)^{\frac {1}{2}},} 101: 4654: 3395: 2921: 2580: 1684: 1036: 580: 496: 252: 212: 86: 4033: 4689: 3197: 122: 3164: 4639: 4502: 4449: 4269: 4203: 4160: 4096: 1740: 1087: 76: 4709: 4619: 373: 142: 56: 4735: 4704: 4520: 4465: 4353: 4287: 4184: 2857: 2556: 137: 4659: 4560: 4537: 4408: 4398: 4373: 4322: 4312: 4233: 4176: 3945:{\displaystyle M_{\text{J}}\propto \rho ^{{\frac {3}{2}}\left(\gamma -{\frac {4}{3}}\right)}.} 3683: 3469: 3401: 3263: 2832: 2531: 1316: 1289: 985: 652: 96: 3535:{\displaystyle PV^{\gamma }={\text{constant}}\rightarrow V\propto P^{-{\frac {1}{\gamma }}}.} 4510: 4457: 4363: 4277: 4204:"Original letter from Isaac Newton to Richard Bentley, dated 17 January 1692/3 (Diplomatic)" 4168: 4104: 255:
of a cloud of gas or dust. It causes the collapse of interstellar gas clouds and subsequent
4426: 4624: 3955: 2731: 2712:{\displaystyle M_{\text{J}}=3\times 10^{4}\left({\frac {T^{3}}{n}}\right)^{\frac {1}{2}}.} 549: 528: 429: 61: 3013: 4506: 4453: 4273: 4164: 4100: 2606: 4605: 4038: 3432: 3426: 2993: 2970: 2927: 1017: 965: 801: 647: 569: 524: 33: 2883: 2040: 1852: 1713: 1666: 520:
gravitational force, and the cloud will collapse, is called Jeans collapse criterion.
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If during the derivation all constants are taken along, the resulting expression is
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is the cloud's mass density (i.e. the cloud's mass divided by the cloud's volume).
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Cosmology's century: an inside history of our modern understanding of the universe
3287:) below which stable oscillations rather than gravitational collapse will occur. 4634: 4629: 600: 576: 264: 71: 66: 27:
Mechanism by which the collapse of interstellar gas clouds causes star formation
4461: 4109: 4084: 3453: 363:{\displaystyle {\frac {dp}{dr}}=-{\frac {G\rho (r)M_{\text{enc}}(r)}{r^{2}}},} 4412: 4377: 4326: 4180: 4644: 4368: 4341: 3680: 3544: 2377:{\displaystyle M_{\text{J}}=\left({\frac {T^{3}}{n}}\right)^{\frac {1}{2}}.} 572: 81: 4515: 4490: 4282: 4257: 4172: 4392: 4306: 2314:
A little algebra leads to the following expression for the critical mass:
17: 3743:{\displaystyle P=K\rho ^{\gamma }\rightarrow T\propto \rho ^{\gamma -1}.} 584: 260: 4311:. Scott Tremaine (2nd ed.). Princeton: Princeton University Press. 596: 588: 4188: 4149: 1739:, work must be done against the gas pressure. During the compression, 4524: 4291: 544:
eventually reach a resting place. Contrary to the writing of Halley,
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The amount of energy released when the sphere contracts from radius
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Falco, M.; Hansen, S. H.; Wojtak, R.; Mamon, G. A. (2013-05-01).
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is, apart from constants, given by the following expression:
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Monthly Notices of the Royal Astronomical Society: Letters
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Philosophical Transactions of the Royal Society of London
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The gravitational potential energy of a sphere with mass
4427:"Jeans Length -- from Eric Weisstein's World of Physics" 4397:. Chichester, West Sussex, U.K.: Wiley. pp. 46–47. 1878:, one arrives at the following expression for the work: 1039:. The condition for gravitational collapse is therefore 1690:
Consider a homogeneous spherical gas cloud with radius
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overcomes pressure forces, and the region undergoes
4682: 4612: 2233:must be expressed in terms of the particle density 274:, which in case of a spherical cloud translates to 4015: 3982: 3944: 3867: 3742: 3670: 3534: 3441: 3417: 3382: 3279: 3236: 3186: 3150: 3130: 3037: 3002: 2982: 2959: 2936: 2912: 2892: 2872: 2848: 2821: 2711: 2625: 2595: 2571: 2547: 2520: 2376: 2304: 2265: 2245: 2225: 2203: 2138: 2078: 2066:is obtained by differentiation this expression to 2058: 2029: 2007: 1964: 1944: 1922: 1870: 1841: 1815: 1795: 1775: 1755: 1731: 1702: 1675: 1634: 1382: 1332: 1305: 1276: 1103: 1075:{\displaystyle t_{\text{ff}}<t_{\text{sound}}.} 1074: 1008: 974: 954: 934: 791: 668: 638: 618: 511: 487: 467: 447: 418: 398: 362: 4495:Philosophical Transactions of the Royal Society A 4262:Philosophical Transactions of the Royal Society A 4089:Monthly Notices of the Royal Astronomical Society 1313:is just the mass contained in a sphere of radius 4232:. Princeton Oxford: Princeton University Press. 251:that describes an instability that leads to the 3247: 2900:is the mean molecular weight of the particles, 2204:{\displaystyle {\frac {M^{2}}{R^{2}}}=nTR^{2}.} 1710:. In order to compress this sphere to a radius 3045:. The formula for Jeans' length then becomes: 2139:{\displaystyle dU={\frac {M^{2}}{R^{2}}}\,dR.} 1849:. Using the ideal gas law, according to which 4590: 3256:is the oscillation wavelength (respectively, 1823:the gas pressure. The work to be done equals 523:The Jeans instability likely determines when 162: 8: 4251: 4249: 259:formation. It occurs when the internal gas 4597: 4583: 4575: 982:is the gas density within the region, and 169: 155: 29: 4514: 4367: 4357: 4281: 4108: 4003: 3995: 3970: 3962: 3922: 3901: 3900: 3887: 3881: 3850: 3846: 3815: 3814: 3795: 3791: 3776: 3763: 3757: 3725: 3706: 3691: 3646: 3608: 3589: 3585: 3552: 3517: 3513: 3495: 3486: 3477: 3434: 3409: 3403: 3366: 3347: 3336: 3321: 3307: 3298: 3292: 3271: 3265: 3226: 3205: 3199: 3172: 3166: 3143: 3114: 3090: 3077: 3070: 3056: 3050: 3029: 3020: 3015: 2995: 2972: 2952: 2929: 2905: 2885: 2865: 2840: 2834: 2805: 2772: 2762: 2748: 2742: 2695: 2680: 2674: 2663: 2644: 2638: 2614: 2608: 2588: 2564: 2539: 2533: 2504: 2489: 2483: 2467: 2454: 2444: 2426: 2421: 2411: 2397: 2391: 2360: 2345: 2339: 2325: 2319: 2293: 2278: 2258: 2238: 2218: 2192: 2171: 2161: 2155: 2153: 2126: 2118: 2108: 2102: 2091: 2071: 2042: 2022: 1991: 1985: 1977: 1957: 1937: 1910: 1904: 1883: 1854: 1828: 1808: 1788: 1768: 1748: 1715: 1695: 1668: 1617: 1613: 1597: 1592: 1585: 1575: 1564: 1552: 1542: 1536: 1522: 1517: 1496: 1481: 1470: 1465: 1459: 1446: 1437: 1432: 1410: 1401: 1395: 1374: 1360: 1351: 1345: 1324: 1318: 1297: 1291: 1259: 1255: 1239: 1234: 1227: 1217: 1201: 1191: 1185: 1177: 1157: 1137: 1131: 1122: 1116: 1095: 1089: 1063: 1050: 1044: 998: 987: 967: 962:is the universal gravitational constant, 947: 917: 913: 897: 892: 885: 875: 862: 842: 823: 814: 808: 780: 768: 758: 752: 736: 727: 719: 705: 696: 687: 681: 660: 654: 631: 611: 504: 480: 460: 431: 411: 381: 375: 349: 329: 307: 281: 279: 231:Learn how and when to remove this message 2633:for the particle density, the result is 194:This article includes a list of general 4394:An Introduction to Stellar Astrophysics 4051: 3248:Jeans' length as oscillation wavelength 1683:) and constants of nature (such as the 109: 48: 32: 4551:Clarke, Cathie; Carswell, Bob (2007). 4016:{\textstyle \gamma <{\frac {4}{3}}} 3983:{\textstyle \gamma >{\frac {4}{3}}} 2273:. This can be done using the relation 4491:"The Stability of a Spherical Nebula" 4258:"The Stability of a Spherical Nebula" 2008:{\displaystyle U={\frac {M^{2}}{R}}.} 455:is the density of the gas (at radius 7: 4747: 270:For stability, the cloud must be in 3456:would travel in the collapse time. 3237:{\textstyle k_{\text{B}}T=GM\mu /r} 4342:"Why does the Jeans Swindle work?" 3187:{\textstyle \lambda _{\text{J}}=r} 200:it lacks sufficient corresponding 25: 2880:is the temperature of the cloud, 2737:The formula for Jeans length is: 4746: 4734: 4723: 4722: 4673: 1104:{\textstyle \lambda _{\text{J}}} 587:support to balance the force of 579:, who considered the process of 185: 40: 1923:{\displaystyle dW=nTR^{2}\,dR.} 4125:"The Jeans Collapse Criterion" 4085:"1957MNRAS.117..104B Page 104" 3837: 3825: 3712: 3633: 3572: 3500: 3449:is the enclosed mass density. 1154: 1144: 839: 829: 442: 436: 399:{\textstyle M_{\text{enc}}(r)} 393: 387: 341: 335: 322: 316: 1: 4442:Plasma Science and Technology 4553:Astrophysical Fluid Dynamics 4532:Longair, Malcolm S. (1998). 4148:Halley, Edmund (1720–1721). 3161:It follows immediately that 3158:is the radius of the cloud. 1783:the (absolute) temperature, 1020:for mean mass per particle ( 4785:Fluid dynamic instabilities 4041:(similar waves in a plasma) 1390:is half the Jeans length): 1084:The resultant Jeans length 4811: 4700:Kelvin–Helmholtz mechanism 4557:Cambridge University Press 4228:Peebles, P. J. E. (2022). 4208:www.newtonproject.ox.ac.uk 3452:It is also the distance a 1803:the particle density, and 1763:be the mass of the cloud, 133:Kelvin–Helmholtz mechanism 4718: 4671: 4391:LeBlanc, Francis (2010). 3418:{\textstyle c_{\text{s}}} 3280:{\textstyle k_{\text{J}}} 2990:and in which we rephrase 2849:{\textstyle k_{\text{B}}} 2548:{\textstyle k_{\text{B}}} 2305:{\displaystyle M=nR^{3}.} 1333:{\textstyle R_{\text{J}}} 1306:{\textstyle M_{\text{J}}} 1009:{\textstyle n=\rho /\mu } 669:{\textstyle c_{\text{s}}} 4775:Concepts in astrophysics 4462:10.1088/2058-6272/aa96fa 548:, in a 1692/3 letter to 4110:10.1093/mnras/117.1.104 1658:Energy-based derivation 272:hydrostatic equilibrium 215:more precise citations. 4655:Pre-main-sequence star 4516:10.1098/rsta.1902.0012 4305:Binney, James (2008). 4283:10.1098/rsta.1902.0012 4173:10.1098/rstl.1720.0006 4083:Bonnor, W. B. (1957). 4017: 3984: 3946: 3869: 3744: 3672: 3536: 3443: 3419: 3396:gravitational constant 3384: 3281: 3238: 3188: 3152: 3132: 3039: 3004: 2984: 2961: 2938: 2922:gravitational constant 2914: 2894: 2874: 2850: 2823: 2713: 2627: 2597: 2581:gravitational constant 2573: 2549: 2522: 2378: 2306: 2267: 2247: 2227: 2205: 2140: 2080: 2060: 2031: 2009: 1966: 1946: 1924: 1872: 1843: 1817: 1797: 1777: 1757: 1733: 1704: 1685:gravitational constant 1677: 1636: 1384: 1334: 1307: 1278: 1105: 1076: 1037:gravitational collapse 1010: 976: 956: 936: 793: 670: 640: 620: 581:gravitational collapse 513: 497:gravitational constant 489: 469: 449: 420: 406:is the enclosed mass, 400: 364: 253:gravitational collapse 87:Pre-main-sequence star 4690:Initial mass function 4489:Jeans, J. H. (1902). 4369:10.1093/mnrasl/sls051 4256:Jeans, J. H. (1902). 4018: 3985: 3947: 3870: 3745: 3673: 3537: 3444: 3420: 3385: 3282: 3239: 3189: 3153: 3133: 3040: 3005: 2985: 2962: 2939: 2915: 2895: 2875: 2851: 2824: 2721: 2714: 2628: 2598: 2574: 2550: 2523: 2379: 2307: 2268: 2248: 2228: 2206: 2141: 2081: 2061: 2032: 2010: 1967: 1947: 1925: 1873: 1844: 1818: 1798: 1778: 1758: 1734: 1705: 1678: 1637: 1385: 1335: 1308: 1279: 1106: 1077: 1011: 977: 957: 937: 794: 671: 646:, and with a gaseous 641: 621: 595:as a function of its 514: 490: 470: 450: 448:{\textstyle \rho (r)} 421: 401: 365: 123:Initial mass function 4683:Theoretical concepts 4640:Young stellar object 4536:. Berlin: Springer. 3994: 3961: 3880: 3756: 3690: 3551: 3476: 3433: 3402: 3291: 3264: 3198: 3165: 3142: 3049: 3038:{\textstyle M/r^{3}} 3014: 2994: 2971: 2951: 2928: 2904: 2884: 2864: 2833: 2741: 2637: 2607: 2587: 2563: 2532: 2390: 2318: 2277: 2257: 2237: 2217: 2152: 2090: 2070: 2041: 2021: 1976: 1956: 1936: 1882: 1853: 1827: 1807: 1787: 1767: 1747: 1741:gravitational energy 1714: 1694: 1667: 1394: 1344: 1317: 1290: 1115: 1088: 1043: 986: 966: 946: 807: 680: 653: 630: 610: 503: 479: 459: 430: 410: 374: 278: 110:Theoretical concepts 77:Young stellar object 4710:Planetary migration 4620:Interstellar medium 4507:1902RSPTA.199....1J 4454:2018PlST...20c5301A 4274:1902RSPTA.199....1J 4165:1720RSPT...31...22H 4129:csep10.phys.utk.edu 4101:1957MNRAS.117..104B 4060:"Jeans instability" 3470:adiabatic processes 2626:{\textstyle m^{-3}} 2431: 1475: 1442: 568:is named after the 143:Planetary migration 57:Interstellar medium 4790:Interstellar media 4780:Effects of gravity 4705:Nebular hypothesis 4665:Herbig–Haro object 4013: 3980: 3942: 3865: 3740: 3668: 3532: 3442:{\textstyle \rho } 3439: 3415: 3380: 3277: 3234: 3184: 3148: 3128: 3035: 3003:{\textstyle \rho } 3000: 2983:{\textstyle 4\pi } 2980: 2957: 2937:{\textstyle \rho } 2934: 2910: 2890: 2870: 2858:Boltzmann constant 2846: 2819: 2709: 2623: 2593: 2569: 2557:Boltzmann constant 2545: 2518: 2417: 2374: 2302: 2263: 2243: 2223: 2201: 2136: 2076: 2056: 2027: 2005: 1962: 1942: 1920: 1868: 1839: 1813: 1793: 1773: 1753: 1729: 1700: 1673: 1632: 1461: 1428: 1380: 1330: 1303: 1274: 1101: 1072: 1006: 975:{\textstyle \rho } 972: 952: 932: 789: 666: 636: 616: 509: 485: 465: 445: 416: 396: 360: 138:Nebular hypothesis 102:Herbig–Haro object 4762: 4761: 4695:Jeans instability 4660:Herbig Ae/Be star 4566:978-0-521-85331-6 4501:(312–320): 1–53. 4404:978-0-470-69957-7 4318:978-0-691-13026-2 4308:Galactic dynamics 4268:(312–320): 1–53. 4034:Bonnor–Ebert mass 4011: 3978: 3930: 3909: 3890: 3858: 3823: 3803: 3784: 3766: 3684:equation of state 3662: 3624: 3597: 3525: 3498: 3412: 3374: 3360: 3339: 3327: 3324: 3301: 3274: 3258:Jeans' wavenumber 3208: 3175: 3122: 3108: 3080: 3059: 2893:{\textstyle \mu } 2843: 2813: 2799: 2775: 2751: 2703: 2689: 2647: 2542: 2512: 2498: 2475: 2461: 2424: 2400: 2368: 2354: 2328: 2213:Next, the radius 2177: 2124: 2059:{\textstyle R-dR} 2000: 1871:{\textstyle p=nT} 1732:{\textstyle R-dR} 1676:{\textstyle \pi } 1625: 1607: 1595: 1558: 1555: 1545: 1520: 1508: 1504: 1489: 1468: 1454: 1435: 1423: 1404: 1377: 1368: 1354: 1327: 1300: 1267: 1249: 1237: 1207: 1204: 1194: 1180: 1169: 1165: 1140: 1125: 1111:is approximately 1098: 1066: 1053: 925: 907: 895: 865: 854: 850: 817: 774: 771: 761: 742: 739: 722: 711: 708: 690: 663: 426:is the pressure, 384: 355: 332: 299: 245:Jeans instability 241: 240: 233: 179: 178: 128:Jeans instability 97:Herbig Ae/Be star 16:(Redirected from 4802: 4750: 4749: 4738: 4726: 4725: 4677: 4676: 4599: 4592: 4585: 4576: 4570: 4547: 4534:Galaxy Formation 4528: 4518: 4480: 4474: 4473: 4437: 4431: 4430: 4423: 4417: 4416: 4388: 4382: 4381: 4371: 4361: 4337: 4331: 4330: 4302: 4296: 4295: 4285: 4253: 4244: 4243: 4225: 4219: 4218: 4216: 4214: 4199: 4193: 4192: 4145: 4139: 4138: 4136: 4135: 4121: 4115: 4114: 4112: 4080: 4074: 4073: 4071: 4070: 4064:Oxford Reference 4056: 4022: 4020: 4019: 4014: 4012: 4004: 3989: 3987: 3986: 3981: 3979: 3971: 3951: 3949: 3948: 3943: 3938: 3937: 3936: 3932: 3931: 3923: 3910: 3902: 3892: 3891: 3888: 3874: 3872: 3871: 3866: 3861: 3860: 3859: 3851: 3841: 3840: 3824: 3816: 3806: 3805: 3804: 3796: 3786: 3785: 3777: 3768: 3767: 3764: 3749: 3747: 3746: 3741: 3736: 3735: 3711: 3710: 3677: 3675: 3674: 3669: 3664: 3663: 3661: 3647: 3626: 3625: 3620: 3609: 3600: 3599: 3598: 3590: 3541: 3539: 3538: 3533: 3528: 3527: 3526: 3518: 3499: 3496: 3491: 3490: 3448: 3446: 3445: 3440: 3424: 3422: 3421: 3416: 3414: 3413: 3410: 3389: 3387: 3386: 3381: 3376: 3375: 3367: 3365: 3361: 3359: 3348: 3341: 3340: 3337: 3328: 3326: 3325: 3322: 3316: 3308: 3303: 3302: 3299: 3286: 3284: 3283: 3278: 3276: 3275: 3272: 3243: 3241: 3240: 3235: 3230: 3210: 3209: 3206: 3193: 3191: 3190: 3185: 3177: 3176: 3173: 3157: 3155: 3154: 3149: 3137: 3135: 3134: 3129: 3124: 3123: 3115: 3113: 3109: 3107: 3096: 3095: 3094: 3082: 3081: 3078: 3071: 3061: 3060: 3057: 3044: 3042: 3041: 3036: 3034: 3033: 3024: 3009: 3007: 3006: 3001: 2989: 2987: 2986: 2981: 2966: 2964: 2963: 2958: 2943: 2941: 2940: 2935: 2919: 2917: 2916: 2911: 2899: 2897: 2896: 2891: 2879: 2877: 2876: 2871: 2855: 2853: 2852: 2847: 2845: 2844: 2841: 2828: 2826: 2825: 2820: 2815: 2814: 2806: 2804: 2800: 2798: 2781: 2777: 2776: 2773: 2763: 2753: 2752: 2749: 2718: 2716: 2715: 2710: 2705: 2704: 2696: 2694: 2690: 2685: 2684: 2675: 2668: 2667: 2649: 2648: 2645: 2632: 2630: 2629: 2624: 2622: 2621: 2602: 2600: 2599: 2594: 2578: 2576: 2575: 2570: 2554: 2552: 2551: 2546: 2544: 2543: 2540: 2527: 2525: 2524: 2519: 2514: 2513: 2505: 2503: 2499: 2494: 2493: 2484: 2477: 2476: 2468: 2466: 2462: 2460: 2459: 2458: 2449: 2448: 2432: 2430: 2425: 2422: 2412: 2402: 2401: 2398: 2383: 2381: 2380: 2375: 2370: 2369: 2361: 2359: 2355: 2350: 2349: 2340: 2330: 2329: 2326: 2311: 2309: 2308: 2303: 2298: 2297: 2272: 2270: 2269: 2264: 2252: 2250: 2249: 2244: 2232: 2230: 2229: 2224: 2210: 2208: 2207: 2202: 2197: 2196: 2178: 2176: 2175: 2166: 2165: 2156: 2145: 2143: 2142: 2137: 2125: 2123: 2122: 2113: 2112: 2103: 2085: 2083: 2082: 2077: 2065: 2063: 2062: 2057: 2036: 2034: 2033: 2028: 2014: 2012: 2011: 2006: 2001: 1996: 1995: 1986: 1971: 1969: 1968: 1963: 1951: 1949: 1948: 1943: 1929: 1927: 1926: 1921: 1909: 1908: 1877: 1875: 1874: 1869: 1848: 1846: 1845: 1842:{\textstyle pdV} 1840: 1822: 1820: 1819: 1814: 1802: 1800: 1799: 1794: 1782: 1780: 1779: 1774: 1762: 1760: 1759: 1754: 1738: 1736: 1735: 1730: 1709: 1707: 1706: 1701: 1682: 1680: 1679: 1674: 1641: 1639: 1638: 1633: 1628: 1627: 1626: 1618: 1612: 1608: 1606: 1605: 1604: 1596: 1593: 1590: 1589: 1576: 1569: 1568: 1563: 1559: 1557: 1556: 1553: 1547: 1546: 1543: 1537: 1527: 1526: 1521: 1518: 1509: 1507: 1506: 1505: 1497: 1491: 1490: 1482: 1474: 1469: 1466: 1460: 1455: 1447: 1441: 1436: 1433: 1424: 1419: 1411: 1406: 1405: 1402: 1389: 1387: 1386: 1381: 1379: 1378: 1375: 1369: 1361: 1356: 1355: 1352: 1339: 1337: 1336: 1331: 1329: 1328: 1325: 1312: 1310: 1309: 1304: 1302: 1301: 1298: 1283: 1281: 1280: 1275: 1270: 1269: 1268: 1260: 1254: 1250: 1248: 1247: 1246: 1238: 1235: 1232: 1231: 1218: 1208: 1206: 1205: 1202: 1196: 1195: 1192: 1186: 1181: 1178: 1170: 1168: 1167: 1166: 1158: 1142: 1141: 1138: 1132: 1127: 1126: 1123: 1110: 1108: 1107: 1102: 1100: 1099: 1096: 1081: 1079: 1078: 1073: 1068: 1067: 1064: 1055: 1054: 1051: 1033: 1032: 1030: 1015: 1013: 1012: 1007: 1002: 981: 979: 978: 973: 961: 959: 958: 953: 941: 939: 938: 933: 928: 927: 926: 918: 912: 908: 906: 905: 904: 896: 893: 890: 889: 876: 866: 863: 855: 853: 852: 851: 843: 824: 819: 818: 815: 798: 796: 795: 790: 788: 787: 779: 775: 773: 772: 769: 763: 762: 759: 753: 743: 741: 740: 737: 728: 723: 720: 712: 710: 709: 706: 697: 692: 691: 688: 675: 673: 672: 667: 665: 664: 661: 645: 643: 642: 637: 625: 623: 622: 617: 529:molecular clouds 518: 516: 515: 510: 494: 492: 491: 486: 474: 472: 471: 466: 454: 452: 451: 446: 425: 423: 422: 417: 405: 403: 402: 397: 386: 385: 382: 369: 367: 366: 361: 356: 354: 353: 344: 334: 333: 330: 308: 300: 298: 290: 282: 247:is a concept in 236: 229: 225: 222: 216: 211:this article by 202:inline citations 189: 188: 181: 171: 164: 157: 44: 30: 21: 4810: 4809: 4805: 4804: 4803: 4801: 4800: 4799: 4765: 4764: 4763: 4758: 4714: 4678: 4674: 4669: 4625:Molecular cloud 4608: 4603: 4573: 4567: 4550: 4544: 4531: 4488: 4484: 4483: 4477: 4439: 4438: 4434: 4425: 4424: 4420: 4405: 4390: 4389: 4385: 4339: 4338: 4334: 4319: 4304: 4303: 4299: 4255: 4254: 4247: 4240: 4227: 4226: 4222: 4212: 4210: 4202:Newton, Isaac. 4201: 4200: 4196: 4147: 4146: 4142: 4133: 4131: 4123: 4122: 4118: 4082: 4081: 4077: 4068: 4066: 4058: 4057: 4053: 4048: 4030: 3992: 3991: 3959: 3958: 3956:adiabatic index 3952: 3915: 3911: 3896: 3883: 3878: 3877: 3842: 3810: 3787: 3772: 3759: 3754: 3753: 3721: 3702: 3688: 3687: 3651: 3642: 3610: 3604: 3581: 3549: 3548: 3509: 3482: 3474: 3473: 3462: 3431: 3430: 3405: 3400: 3399: 3352: 3343: 3342: 3332: 3317: 3309: 3294: 3289: 3288: 3267: 3262: 3261: 3250: 3201: 3196: 3195: 3168: 3163: 3162: 3140: 3139: 3097: 3086: 3073: 3072: 3066: 3065: 3052: 3047: 3046: 3025: 3012: 3011: 2992: 2991: 2969: 2968: 2960:{\textstyle 15} 2949: 2948: 2926: 2925: 2902: 2901: 2882: 2881: 2862: 2861: 2836: 2831: 2830: 2782: 2768: 2764: 2758: 2757: 2744: 2739: 2738: 2732:Sir James Jeans 2724: 2676: 2670: 2669: 2659: 2640: 2635: 2634: 2610: 2605: 2604: 2585: 2584: 2561: 2560: 2535: 2530: 2529: 2485: 2479: 2478: 2450: 2440: 2433: 2413: 2407: 2406: 2393: 2388: 2387: 2341: 2335: 2334: 2321: 2316: 2315: 2289: 2275: 2274: 2255: 2254: 2235: 2234: 2215: 2214: 2188: 2167: 2157: 2150: 2149: 2114: 2104: 2088: 2087: 2068: 2067: 2039: 2038: 2019: 2018: 1987: 1974: 1973: 1954: 1953: 1934: 1933: 1900: 1880: 1879: 1851: 1850: 1825: 1824: 1805: 1804: 1785: 1784: 1765: 1764: 1745: 1744: 1712: 1711: 1692: 1691: 1665: 1664: 1660: 1647: 1645:"Jeans swindle" 1591: 1581: 1580: 1571: 1570: 1548: 1538: 1532: 1531: 1516: 1492: 1477: 1476: 1412: 1397: 1392: 1391: 1370: 1347: 1342: 1341: 1320: 1315: 1314: 1293: 1288: 1287: 1233: 1223: 1222: 1213: 1212: 1197: 1187: 1153: 1143: 1133: 1118: 1113: 1112: 1091: 1086: 1085: 1059: 1046: 1041: 1040: 1028: 1026: 1021: 984: 983: 964: 963: 944: 943: 891: 881: 880: 871: 870: 838: 828: 810: 805: 804: 764: 754: 748: 747: 732: 701: 683: 678: 677: 656: 651: 650: 628: 627: 608: 607: 562: 550:Richard Bentley 537: 501: 500: 477: 476: 457: 456: 428: 427: 408: 407: 377: 372: 371: 345: 325: 309: 291: 283: 276: 275: 237: 226: 220: 217: 207:Please help to 206: 190: 186: 175: 62:Molecular cloud 28: 23: 22: 15: 12: 11: 5: 4808: 4806: 4798: 4797: 4795:Star formation 4792: 4787: 4782: 4777: 4767: 4766: 4760: 4759: 4757: 4756: 4744: 4732: 4719: 4716: 4715: 4713: 4712: 4707: 4702: 4697: 4692: 4686: 4684: 4680: 4679: 4672: 4670: 4668: 4667: 4662: 4657: 4652: 4647: 4642: 4637: 4632: 4627: 4622: 4616: 4614: 4613:Object classes 4610: 4609: 4606:Star formation 4604: 4602: 4601: 4594: 4587: 4579: 4572: 4571: 4565: 4548: 4542: 4529: 4485: 4482: 4481: 4475: 4432: 4418: 4403: 4383: 4332: 4317: 4297: 4245: 4238: 4220: 4194: 4159:(364): 22–24. 4140: 4116: 4075: 4050: 4049: 4047: 4044: 4043: 4042: 4039:Langmuir waves 4036: 4029: 4026: 4010: 4007: 4002: 3999: 3977: 3974: 3969: 3966: 3941: 3935: 3929: 3926: 3921: 3918: 3914: 3908: 3905: 3899: 3895: 3886: 3864: 3857: 3854: 3849: 3845: 3839: 3836: 3833: 3830: 3827: 3822: 3819: 3813: 3809: 3802: 3799: 3794: 3790: 3783: 3780: 3775: 3771: 3762: 3739: 3734: 3731: 3728: 3724: 3720: 3717: 3714: 3709: 3705: 3701: 3698: 3695: 3667: 3660: 3657: 3654: 3650: 3645: 3641: 3638: 3635: 3632: 3629: 3623: 3619: 3616: 3613: 3607: 3603: 3596: 3593: 3588: 3584: 3580: 3577: 3574: 3571: 3568: 3565: 3562: 3559: 3556: 3531: 3524: 3521: 3516: 3512: 3508: 3505: 3502: 3494: 3489: 3485: 3481: 3467: 3461: 3458: 3438: 3408: 3379: 3373: 3370: 3364: 3358: 3355: 3351: 3346: 3335: 3331: 3320: 3315: 3312: 3306: 3297: 3270: 3249: 3246: 3233: 3229: 3225: 3222: 3219: 3216: 3213: 3204: 3183: 3180: 3171: 3151:{\textstyle r} 3147: 3127: 3121: 3118: 3112: 3106: 3103: 3100: 3093: 3089: 3085: 3076: 3069: 3064: 3055: 3032: 3028: 3023: 3019: 2999: 2979: 2976: 2956: 2933: 2913:{\textstyle G} 2909: 2889: 2873:{\textstyle T} 2869: 2839: 2818: 2812: 2809: 2803: 2797: 2794: 2791: 2788: 2785: 2780: 2771: 2767: 2761: 2756: 2747: 2723: 2720: 2708: 2702: 2699: 2693: 2688: 2683: 2679: 2673: 2666: 2662: 2658: 2655: 2652: 2643: 2620: 2617: 2613: 2596:{\textstyle m} 2592: 2572:{\textstyle G} 2568: 2538: 2517: 2511: 2508: 2502: 2497: 2492: 2488: 2482: 2474: 2471: 2465: 2457: 2453: 2447: 2443: 2439: 2436: 2429: 2420: 2416: 2410: 2405: 2396: 2373: 2367: 2364: 2358: 2353: 2348: 2344: 2338: 2333: 2324: 2301: 2296: 2292: 2288: 2285: 2282: 2266:{\textstyle M} 2262: 2246:{\textstyle n} 2242: 2226:{\textstyle R} 2222: 2200: 2195: 2191: 2187: 2184: 2181: 2174: 2170: 2164: 2160: 2135: 2132: 2129: 2121: 2117: 2111: 2107: 2101: 2098: 2095: 2079:{\textstyle R} 2075: 2055: 2052: 2049: 2046: 2030:{\textstyle R} 2026: 2004: 1999: 1994: 1990: 1984: 1981: 1965:{\textstyle R} 1961: 1945:{\textstyle M} 1941: 1919: 1916: 1913: 1907: 1903: 1899: 1896: 1893: 1890: 1887: 1867: 1864: 1861: 1858: 1838: 1835: 1832: 1816:{\textstyle p} 1812: 1796:{\textstyle n} 1792: 1776:{\textstyle T} 1772: 1756:{\textstyle M} 1752: 1728: 1725: 1722: 1719: 1703:{\textstyle R} 1699: 1672: 1659: 1656: 1646: 1643: 1631: 1624: 1621: 1616: 1611: 1603: 1600: 1588: 1584: 1579: 1574: 1567: 1562: 1551: 1541: 1535: 1530: 1525: 1515: 1512: 1503: 1500: 1495: 1488: 1485: 1480: 1473: 1464: 1458: 1453: 1450: 1445: 1440: 1431: 1427: 1422: 1418: 1415: 1409: 1400: 1373: 1367: 1364: 1359: 1350: 1323: 1296: 1273: 1266: 1263: 1258: 1253: 1245: 1242: 1230: 1226: 1221: 1216: 1211: 1200: 1190: 1184: 1176: 1173: 1164: 1161: 1156: 1152: 1149: 1146: 1136: 1130: 1121: 1094: 1071: 1062: 1058: 1049: 1018:number density 1005: 1001: 997: 994: 991: 971: 955:{\textstyle G} 951: 931: 924: 921: 916: 911: 903: 900: 888: 884: 879: 874: 869: 861: 858: 849: 846: 841: 837: 834: 831: 827: 822: 813: 802:free-fall time 786: 783: 778: 767: 757: 751: 746: 735: 731: 726: 718: 715: 704: 700: 695: 686: 659: 639:{\textstyle M} 635: 619:{\textstyle R} 615: 561: 558: 536: 533: 525:star formation 512:{\textstyle r} 508: 488:{\textstyle G} 484: 468:{\textstyle r} 464: 444: 441: 438: 435: 419:{\textstyle p} 415: 395: 392: 389: 380: 359: 352: 348: 343: 340: 337: 328: 324: 321: 318: 315: 312: 306: 303: 297: 294: 289: 286: 239: 238: 193: 191: 184: 177: 176: 174: 173: 166: 159: 151: 148: 147: 146: 145: 140: 135: 130: 125: 120: 112: 111: 107: 106: 105: 104: 99: 94: 89: 84: 79: 74: 69: 64: 59: 51: 50: 49:Object classes 46: 45: 37: 36: 34:Star formation 26: 24: 14: 13: 10: 9: 6: 4: 3: 2: 4807: 4796: 4793: 4791: 4788: 4786: 4783: 4781: 4778: 4776: 4773: 4772: 4770: 4755: 4754: 4745: 4743: 4742: 4737: 4733: 4731: 4730: 4721: 4720: 4717: 4711: 4708: 4706: 4703: 4701: 4698: 4696: 4693: 4691: 4688: 4687: 4685: 4681: 4666: 4663: 4661: 4658: 4656: 4653: 4651: 4648: 4646: 4643: 4641: 4638: 4636: 4633: 4631: 4628: 4626: 4623: 4621: 4618: 4617: 4615: 4611: 4607: 4600: 4595: 4593: 4588: 4586: 4581: 4580: 4577: 4568: 4562: 4558: 4555:. Cambridge: 4554: 4549: 4545: 4543:3-540-63785-0 4539: 4535: 4530: 4526: 4522: 4517: 4512: 4508: 4504: 4500: 4496: 4492: 4487: 4486: 4479: 4476: 4471: 4467: 4463: 4459: 4455: 4451: 4448:(3): 035301. 4447: 4443: 4436: 4433: 4428: 4422: 4419: 4414: 4410: 4406: 4400: 4396: 4395: 4387: 4384: 4379: 4375: 4370: 4365: 4360: 4355: 4351: 4347: 4343: 4336: 4333: 4328: 4324: 4320: 4314: 4310: 4309: 4301: 4298: 4293: 4289: 4284: 4279: 4275: 4271: 4267: 4263: 4259: 4252: 4250: 4246: 4241: 4239:9780691196022 4235: 4231: 4224: 4221: 4209: 4205: 4198: 4195: 4190: 4186: 4182: 4178: 4174: 4170: 4166: 4162: 4158: 4154: 4151: 4144: 4141: 4130: 4126: 4120: 4117: 4111: 4106: 4102: 4098: 4094: 4090: 4086: 4079: 4076: 4065: 4061: 4055: 4052: 4045: 4040: 4037: 4035: 4032: 4031: 4027: 4025: 4008: 4005: 4000: 3997: 3975: 3972: 3967: 3964: 3957: 3939: 3933: 3927: 3924: 3919: 3916: 3912: 3906: 3903: 3897: 3893: 3884: 3875: 3862: 3855: 3852: 3847: 3843: 3834: 3831: 3828: 3820: 3817: 3811: 3807: 3800: 3797: 3792: 3788: 3781: 3778: 3773: 3769: 3760: 3750: 3737: 3732: 3729: 3726: 3722: 3718: 3715: 3707: 3703: 3699: 3696: 3693: 3685: 3682: 3678: 3665: 3658: 3655: 3652: 3648: 3643: 3639: 3636: 3630: 3627: 3621: 3617: 3614: 3611: 3605: 3601: 3594: 3591: 3586: 3582: 3578: 3575: 3569: 3566: 3563: 3560: 3557: 3554: 3546: 3529: 3522: 3519: 3514: 3510: 3506: 3503: 3492: 3487: 3483: 3479: 3471: 3466: 3460:Fragmentation 3459: 3457: 3455: 3450: 3436: 3428: 3406: 3397: 3393: 3377: 3371: 3368: 3362: 3356: 3353: 3349: 3344: 3333: 3329: 3318: 3313: 3310: 3304: 3295: 3268: 3259: 3255: 3254:Jeans' length 3245: 3231: 3227: 3223: 3220: 3217: 3214: 3211: 3202: 3181: 3178: 3169: 3159: 3145: 3125: 3119: 3116: 3110: 3104: 3101: 3098: 3091: 3087: 3083: 3074: 3067: 3062: 3053: 3030: 3026: 3021: 3017: 2997: 2977: 2974: 2954: 2945: 2931: 2923: 2907: 2887: 2867: 2859: 2837: 2816: 2810: 2807: 2801: 2795: 2792: 2789: 2786: 2783: 2778: 2769: 2765: 2759: 2754: 2745: 2735: 2733: 2728: 2727:Jeans' length 2722:Jeans' length 2719: 2706: 2700: 2697: 2691: 2686: 2681: 2677: 2671: 2664: 2660: 2656: 2653: 2650: 2641: 2618: 2615: 2611: 2590: 2582: 2566: 2558: 2536: 2515: 2509: 2506: 2500: 2495: 2490: 2486: 2480: 2472: 2469: 2463: 2455: 2451: 2445: 2441: 2437: 2434: 2427: 2418: 2414: 2408: 2403: 2394: 2384: 2371: 2365: 2362: 2356: 2351: 2346: 2342: 2336: 2331: 2322: 2312: 2299: 2294: 2290: 2286: 2283: 2280: 2260: 2253:and the mass 2240: 2220: 2211: 2198: 2193: 2189: 2185: 2182: 2179: 2172: 2168: 2162: 2158: 2146: 2133: 2130: 2127: 2119: 2115: 2109: 2105: 2099: 2096: 2093: 2073: 2053: 2050: 2047: 2044: 2024: 2015: 2002: 1997: 1992: 1988: 1982: 1979: 1959: 1939: 1930: 1917: 1914: 1911: 1905: 1901: 1897: 1894: 1891: 1888: 1885: 1865: 1862: 1859: 1856: 1836: 1833: 1830: 1810: 1790: 1770: 1750: 1742: 1726: 1723: 1720: 1717: 1697: 1688: 1686: 1670: 1657: 1655: 1651: 1644: 1642: 1629: 1622: 1619: 1614: 1609: 1601: 1598: 1586: 1582: 1577: 1572: 1565: 1560: 1549: 1539: 1533: 1528: 1523: 1513: 1510: 1501: 1498: 1493: 1486: 1483: 1478: 1471: 1462: 1456: 1451: 1448: 1443: 1438: 1429: 1425: 1420: 1416: 1413: 1407: 1398: 1371: 1365: 1362: 1357: 1348: 1321: 1294: 1284: 1271: 1264: 1261: 1256: 1251: 1243: 1240: 1228: 1224: 1219: 1214: 1209: 1198: 1188: 1182: 1174: 1171: 1162: 1159: 1150: 1147: 1134: 1128: 1119: 1092: 1082: 1069: 1060: 1056: 1047: 1038: 1024: 1019: 1003: 999: 995: 992: 989: 969: 949: 929: 922: 919: 914: 909: 901: 898: 886: 882: 877: 872: 867: 859: 856: 847: 844: 835: 832: 825: 820: 811: 803: 784: 781: 776: 765: 755: 749: 744: 733: 729: 724: 716: 713: 702: 698: 693: 684: 657: 649: 633: 613: 604: 602: 598: 594: 590: 586: 582: 578: 574: 571: 567: 559: 557: 553: 551: 547: 542: 541:Edmund Halley 534: 532: 530: 526: 521: 506: 498: 482: 462: 439: 433: 413: 390: 378: 357: 350: 346: 338: 326: 319: 313: 310: 304: 301: 295: 292: 287: 284: 273: 268: 266: 262: 258: 254: 250: 246: 235: 232: 224: 214: 210: 204: 203: 197: 192: 183: 182: 172: 167: 165: 160: 158: 153: 152: 150: 149: 144: 141: 139: 136: 134: 131: 129: 126: 124: 121: 119: 116: 115: 114: 113: 108: 103: 100: 98: 95: 93: 90: 88: 85: 83: 80: 78: 75: 73: 70: 68: 65: 63: 60: 58: 55: 54: 53: 52: 47: 43: 39: 38: 35: 31: 19: 4752: 4741:Stars portal 4740: 4728: 4694: 4650:T Tauri star 4552: 4533: 4498: 4494: 4478: 4445: 4441: 4435: 4421: 4393: 4386: 4352:(1): L6–L9. 4349: 4345: 4335: 4307: 4300: 4265: 4261: 4229: 4223: 4211:. Retrieved 4207: 4197: 4156: 4152: 4143: 4132:. Retrieved 4128: 4119: 4092: 4088: 4078: 4067:. Retrieved 4063: 4054: 3953: 3752:Jeans mass, 3751: 3679: 3542: 3463: 3451: 3391: 3257: 3253: 3251: 3160: 2946: 2736: 2726: 2725: 2385: 2313: 2212: 2147: 2016: 1931: 1689: 1661: 1652: 1648: 1285: 1083: 1022: 605: 565: 563: 554: 546:Isaac Newton 538: 522: 269: 249:astrophysics 244: 242: 227: 218: 199: 127: 92:T Tauri star 4635:Dark nebula 4630:Bok globule 4213:11 November 3427:sound speed 1952:and radius 1016:is the gas 648:sound speed 601:temperature 577:James Jeans 265:James Jeans 213:introducing 72:Dark nebula 67:Bok globule 4769:Categories 4134:2024-01-05 4069:2024-01-05 4046:References 3681:Polytropic 3454:sound wave 2037:to radius 1554: km/s 1203: km/s 770: km/s 566:Jeans mass 560:Jeans mass 527:occurs in 221:April 2022 196:references 18:Jeans mass 4645:Protostar 4470:103819409 4413:475440765 4378:1745-3933 4359:1210.3363 4327:195749071 4181:0260-7085 3998:γ 3965:γ 3920:− 3917:γ 3898:ρ 3894:∝ 3848:− 3844:ρ 3832:− 3829:γ 3812:ρ 3808:∝ 3793:− 3789:ρ 3770:∝ 3730:− 3727:γ 3723:ρ 3719:∝ 3713:→ 3708:γ 3704:ρ 3656:− 3653:γ 3649:γ 3640:∝ 3634:⇒ 3628:∝ 3622:γ 3615:− 3612:γ 3595:γ 3587:− 3579:⋅ 3573:⇒ 3545:ideal gas 3523:γ 3515:− 3507:∝ 3501:→ 3488:γ 3437:ρ 3357:ρ 3350:π 3314:π 3296:λ 3224:μ 3170:λ 3105:μ 3063:≈ 3054:λ 2998:ρ 2978:π 2932:ρ 2888:μ 2796:ρ 2793:μ 2787:π 2746:λ 2657:× 2616:− 2438:π 2048:− 1721:− 1671:π 1615:− 1599:− 1529:⋅ 1524:⊙ 1511:≈ 1494:ρ 1457:⋅ 1449:π 1426:ρ 1417:π 1372:λ 1257:− 1241:− 1210:⋅ 1183:⋅ 1172:≈ 1151:ρ 1120:λ 1093:λ 1031:10 g 1004:μ 996:ρ 970:ρ 915:− 899:− 868:⋅ 864: Myr 857:≈ 836:ρ 782:− 745:⋅ 725:⋅ 721: Myr 714:≈ 573:physicist 539:In 1720, 434:ρ 314:ρ 305:− 118:Accretion 82:Protostar 4729:Category 4028:See also 3497:constant 1594: cm 1236: cm 1179: pc 894: cm 738: pc 585:pressure 261:pressure 4753:Commons 4503:Bibcode 4450:Bibcode 4270:Bibcode 4161:Bibcode 4097:Bibcode 4095:: 104. 3954:If the 3543:For an 3425:is the 3394:is the 2924:, and 2920:is the 2856:is the 2555:is the 1519: M 626:, mass 597:density 589:gravity 570:British 535:History 495:is the 209:improve 4563:  4540:  4523:  4468:  4411:  4401:  4376:  4325:  4315:  4290:  4236:  4189:103379 4187:  4179:  3876:Thus, 3429:, and 3390:where 3138:where 2829:where 2583:, and 2528:where 942:where 499:, and 370:where 198:, but 4525:90845 4521:JSTOR 4466:S2CID 4354:arXiv 4292:90845 4288:JSTOR 4185:JSTOR 3194:when 2086:, so 1065:sound 689:sound 4561:ISBN 4538:ISBN 4409:OCLC 4399:ISBN 4374:ISSN 4323:OCLC 4313:ISBN 4234:ISBN 4215:2023 4177:ISSN 4001:< 3968:> 3468:For 3252:The 2967:and 2579:the 1057:< 599:and 593:mass 575:Sir 564:The 257:star 243:The 4511:doi 4499:199 4458:doi 4364:doi 4350:431 4278:doi 4266:199 4169:doi 4105:doi 4093:117 3010:as 2415:375 1550:0.2 1199:0.2 1175:0.4 1027:3.9 766:0.2 734:0.1 717:0.5 475:), 383:enc 331:enc 4771:: 4559:. 4519:. 4509:. 4497:. 4493:. 4464:. 4456:. 4446:20 4444:. 4407:. 4372:. 4362:. 4348:. 4344:. 4321:. 4286:. 4276:. 4264:. 4260:. 4248:^ 4206:. 4183:. 4175:. 4167:. 4157:31 4155:. 4127:. 4103:. 4091:. 4087:. 4062:. 3686:, 3547:, 3472:, 3398:, 3260:, 2955:15 2860:, 2766:15 2661:10 2559:, 1583:10 1225:10 1052:ff 1025:= 883:10 816:ff 531:. 267:. 4598:e 4591:t 4584:v 4569:. 4546:. 4527:. 4513:: 4505:: 4472:. 4460:: 4452:: 4429:. 4415:. 4380:. 4366:: 4356:: 4329:. 4294:. 4280:: 4272:: 4242:. 4217:. 4191:. 4171:: 4163:: 4137:. 4113:. 4107:: 4099:: 4072:. 4009:3 4006:4 3976:3 3973:4 3940:. 3934:) 3928:3 3925:4 3913:( 3907:2 3904:3 3889:J 3885:M 3863:. 3856:2 3853:1 3838:) 3835:1 3826:( 3821:2 3818:3 3801:2 3798:1 3782:2 3779:3 3774:T 3765:J 3761:M 3738:. 3733:1 3716:T 3700:K 3697:= 3694:P 3666:. 3659:1 3644:T 3637:P 3631:T 3618:1 3606:P 3602:= 3592:1 3583:P 3576:P 3570:T 3567:R 3564:n 3561:= 3558:V 3555:P 3530:. 3520:1 3511:P 3504:V 3493:= 3484:V 3480:P 3411:s 3407:c 3392:G 3378:, 3372:2 3369:1 3363:) 3354:G 3345:( 3338:s 3334:c 3330:= 3323:J 3319:k 3311:2 3305:= 3300:J 3273:J 3269:k 3232:r 3228:/ 3221:M 3218:G 3215:= 3212:T 3207:B 3203:k 3182:r 3179:= 3174:J 3146:r 3126:. 3120:2 3117:1 3111:) 3102:M 3099:G 3092:3 3088:r 3084:T 3079:B 3075:k 3068:( 3058:J 3031:3 3027:r 3022:/ 3018:M 2975:4 2908:G 2868:T 2842:B 2838:k 2817:, 2811:2 2808:1 2802:) 2790:G 2784:4 2779:T 2774:B 2770:k 2760:( 2755:= 2750:J 2707:. 2701:2 2698:1 2692:) 2687:n 2682:3 2678:T 2672:( 2665:4 2654:3 2651:= 2646:J 2642:M 2619:3 2612:m 2591:m 2567:G 2541:B 2537:k 2516:, 2510:2 2507:1 2501:) 2496:n 2491:3 2487:T 2481:( 2473:2 2470:1 2464:) 2456:3 2452:G 2446:4 2442:m 2435:4 2428:3 2423:B 2419:k 2409:( 2404:= 2399:J 2395:M 2372:. 2366:2 2363:1 2357:) 2352:n 2347:3 2343:T 2337:( 2332:= 2327:J 2323:M 2300:. 2295:3 2291:R 2287:n 2284:= 2281:M 2261:M 2241:n 2221:R 2199:. 2194:2 2190:R 2186:T 2183:n 2180:= 2173:2 2169:R 2163:2 2159:M 2134:. 2131:R 2128:d 2120:2 2116:R 2110:2 2106:M 2100:= 2097:U 2094:d 2074:R 2054:R 2051:d 2045:R 2025:R 2003:. 1998:R 1993:2 1989:M 1983:= 1980:U 1960:R 1940:M 1918:. 1915:R 1912:d 1906:2 1902:R 1898:T 1895:n 1892:= 1889:W 1886:d 1866:T 1863:n 1860:= 1857:p 1837:V 1834:d 1831:p 1811:p 1791:n 1771:T 1751:M 1727:R 1724:d 1718:R 1698:R 1630:. 1623:2 1620:1 1610:) 1602:3 1587:3 1578:n 1573:( 1566:3 1561:) 1544:s 1540:c 1534:( 1514:2 1502:2 1499:1 1487:2 1484:3 1479:G 1472:3 1467:s 1463:c 1452:6 1444:= 1439:3 1434:J 1430:R 1421:3 1414:4 1408:= 1403:J 1399:M 1376:J 1366:2 1363:1 1358:= 1353:J 1349:R 1340:( 1326:J 1322:R 1299:J 1295:M 1272:. 1265:2 1262:1 1252:) 1244:3 1229:3 1220:n 1215:( 1193:s 1189:c 1163:2 1160:1 1155:) 1148:G 1145:( 1139:s 1135:c 1129:= 1124:J 1097:J 1070:. 1061:t 1048:t 1029:Ă— 1023:ÎĽ 1000:/ 993:= 990:n 950:G 930:, 923:2 920:1 910:) 902:3 887:3 878:n 873:( 860:2 848:2 845:1 840:) 833:G 830:( 826:1 821:= 812:t 785:1 777:) 760:s 756:c 750:( 730:R 707:s 703:c 699:R 694:= 685:t 662:s 658:c 634:M 614:R 507:r 483:G 463:r 443:) 440:r 437:( 414:p 394:) 391:r 388:( 379:M 358:, 351:2 347:r 342:) 339:r 336:( 327:M 323:) 320:r 317:( 311:G 302:= 296:r 293:d 288:p 285:d 234:) 228:( 223:) 219:( 205:. 170:e 163:t 156:v 20:)

Index

Jeans mass
Star formation

Interstellar medium
Molecular cloud
Bok globule
Dark nebula
Young stellar object
Protostar
Pre-main-sequence star
T Tauri star
Herbig Ae/Be star
Herbig–Haro object
Accretion
Initial mass function
Jeans instability
Kelvin–Helmholtz mechanism
Nebular hypothesis
Planetary migration
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