Thermal instability in interstellar clouds

A. E. Dudorov ; S. O. Fomin

Čelâbinskij fiziko-matematičeskij žurnal, Tome 4 (2019) no. 3, pp. 355-370.

Résumé

Thermal instability of magnetized interstellar atomic clouds is investigated with the method of small perturbations. The dispersion relation is obtained for model heating and cooling functions as well as for radiative recombinations and ionization by cosmic rays. The dispersion relation is solved numerically with Bairstow method. It was shown that for model cooling function $\Lambda \propto T^\zeta $ isobaric instability develops for $\zeta 0.2$. In the cold diffuse clouds can develop instabilities of slow magnetosonic waves for $\zeta >1$. Also instability of standing waves can arise at $0.2\zeta 1$. Applications to the cold neutral medium and warm neutral medium are considered.

Détail

Keywords: instability, magnetic field, interstellar medium, dispersion equation.

Bibliographie

[1] G. B. Field, “Thermal instability”, Astrophysical Journal, 142 (1965), 531 | DOI

[2] Pikel'ner S.B., “Heating of the interstellar gas by subcosmic rays, and the formation of clouds”, Astronomical journal, 44 (1967), 915

[3] G. B. Field, D. W. Goldsmith, H. J. Habing, “Cosmic-ray heating of the interstellar gas”, Astrophysical Journal Letters, 155 (1969), L149 | DOI

[4] C. F. McKee, J. P. Ostriker, “A theory of the interstellar medium — three components regulated by supernova explosions in an inhomogeneous substrate”, Astrophysical Journal, 218 (1977), 148–169 | DOI

[5] B. T. Draine, Physics of the Interstellar and Intergalactic Medium, Princeton University Press, Princeton, 2011, 560 pp. | Zbl

[6] P. André, J. Di Francesco, D. Ward-Thompson et al., “From filamentary networks to dense cores in molecular clouds: toward a new paradigm for star formation”, Protostars and Planets VI, eds. H. Beuther, R. S. Klessen, C. P. Dullemond, T. Henning, University of Arizona Press, Tucson, 2014, 27–51, 944 pp.

[7] C. Heiles, “Tiny-scale atomic structure and the cold neutral medium”, Astrophysical Journal, 481 (1997), 193–204 | DOI

[8] S. Stanimirović, J. M. Weisberg, Z. Pei, K. Tuttle, J. T. Green, “Arecibo multi-epoch H I absorption measurements against pulsars: tiny-scale atomic structure”, Astrophysical Journal, 720 (2010), 415–434 | DOI

[9] S. Stanimirović, J. M. Weisberg, E. G. Zweibel, “Atomic and ionized microstructures in the diffuse interstellar medium”, Annual Review of Astronomy and Astrophysics, 56 (2018), 489–540 | DOI

[10] Ye. Wang, G. J. Ferland, M. L. Lykins et al., “Radiative cooling II: effects of density and metallicity”, Monthly Notices of the Royal Astronomical Society, 440:4 (2014), 3100–3112 | DOI

[11] B. P. Flannery, W. H. Press, “An ionization-coupled acoustic instability of the interstellar medium”, Astrophysical Journal, 231 (1979), 688–696 | DOI

[12] A. Dalgarno, R. A. McCray, “Heating and ionization of HI regions”, Annual Review of Astronomy and Astrophysics, 10 (1972), 375 | DOI

[13] E. L. O. Bakes, A. G. G. M. Tielens, “The photoelectric heating mechanism for very small graphitic grains and polycyclic aromatic hydrocarbons”, Astrophysical Journal, 427:2 (1994), 822–838 | DOI

[14] C. Heiles, T. H. Troland, “The millennium Arecibo 21 centimeter absorption-line survey. IV. Statistics of magnetic field, column density, and turbulence”, Astrophysical Journal, 624:2 (2005), 773–793 | DOI

[15] Kadomtsev B.B., Collective plasma phenomena, Nauka Publ., Moscow, 1976, 240 pp. (In Russ.)

[16] A. E. Dudorov, C. E. Stepanov, “Thermal instability in magnetized interstellar clouds”, Astronomical and Astrophysical Transactions, 18 (1999), 101–108 | DOI | MR

[17] A. E. Dudorov, C. E. Stepanov, S. O. Fomin, S. A. Khaibrakhmanov, “Magnetic ionization-thermal instability”, Monthly Notices of the Royal Astronomical Society, 487:1 (2019), 942–951 | DOI

[18] L. Spitzer, Physical Processes in the Interstellar Medium, Wiley-Interscience, New York, 1978, 333 pp. | MR

[19] A / H. J. Habing, “The interstellar radiation density between 912 A and 2400”, Bulletin of the Astronomical Institutes of the Netherlands, 19 (1968), 421

[20] M. G. Wolfire, D. Hollenbach, C. F. McKee, A. G. G. M. Tielens, E. L. O. Bakes, “The neutral atomic phases of the interstellar medium”, Astrophysical Journal, 443:1 (1995), 152–168 | DOI

[21] M. J. Seaton, “Radiative recombination of hydrogenic ions”, Monthly Notices of the Royal Astronomical Society, 119 (1959), 81 | DOI | MR

[22] T. Yoneyama, “Thermal instability in reacting gas”, Publications of the Astronomical Society of Japan, 25 (1973), 349

[23] E. Corbelli, A. Ferrara, “Instabilities in photoionized interstellar gas”, Astrophysical Journal, 447 (1995), 708 | DOI

[24] K. V. Krasnobaev, R. R. Tagirova, “Isentropic thermal instability in atomic surface layers of photodissociation regions”, Monthly Notices of the Royal Astronomical Society, 469:2 (2017), 1403–1413 | DOI

[25] D. Pequignot, “Populations of the O I metastable levels”, Astronomy and Astrophysics, 231:2 (1990), 499–508

[26] D. Pequignot, “(Erratum) Populations of the O I metastable levels”, Astronomy and Astrophysics, 313 (1996), 1026–1026

[27] S. L. W. McMillan, B. P. Flannery, W. H. Press, “Nonlinear hydrodynamics of acoustic instabilities in diffuse clouds”, Astrophysical Journal, 240 (1980), 488–498 | DOI