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1.
We have observed 10 solar bursts during the thermal phase using the Haystack radio telescope at 22 GHz. We show that these high frequency flux observations, when compared with soft X-ray band fluxes, give useful information about the temperature profile in the flare loops. The microwave and X-ray band fluxes provide determinations of the maximum loop temperature, the total emission measure, and the index of the differential emission measure (q(T)/T = cT–1). The special case of an isothermal loop ( = ) has been considered previously by Thomas et al. (1985), and we confirm their diagnostic calculations for the GOES X-ray bands, but find that the flare loops we observed departed significantly from the isothermal regime. Our results ( = 1–3.5) imply that, during the late phases of flares, condensation cooling ( 3.5) competes with radiative cooling ( 1.5). Further, our results appear to be in good agreement with previous deductions from XUV rocket spectra ( 2–3). 相似文献
2.
We analyzed simultaneous EUV images from the Transition Region And Coronal Explorer (TRACE) and H and H filtergrams from Huairou Solar Observing Station (HSOS). In active region NOAA 8307, an H C5.5 flare occurred near 06:10 UT on 23 August 1998. In this paper, we concentrated on loop–loop interaction, as well as their relationship to the C5.5 flare. We find that while opposite polarity magnetic fields cancelled each other, H bright points appeared, and then the flare occurred. Looking at EUV images, we noticed that a TRACE flare, associated with the C5.5 flare in H and H filtergrams, first appeared as patch-shaped structures, then the flare patches expanded to form bright loops. We used a new numerical technique to extrapolate the chromospheric and coronal magnetic field. Magnetic field loops, which linked flare ribbons, were found. It was suggested that loop interaction in the active region was the cause of the TRACE and H flare; the magnetic topological structures were clearly demonstrated and the TRACE flare was probably due to the interaction among energetic low-lying and other longer (higher) magnetic loops. Each primary flare kernel, seen from H, H filtergrams, and EUV images, was located near the footpoints of several interacting loops. 相似文献
3.
-- () ., , , , , . , , . , . 相似文献
4.
H. Zirin 《Solar physics》1978,58(1):95-120
I have studied a number of flares for which good X-ray and optical data were available. An average lag of 5.5 s between hard X-ray (HXR) start and H start, and HXR peak and Ha peak was found for 41 flares for which determination was possible. Allowing for time constants the time lag is zero. The peak H lasts until 5–6 keV soft X-ray (SXR) peak. The level of H intensity is determined by the SXR flux.Multiple spikes in HXR appear to correspond to different occurrences in the flare development. Flares with HXR always have a fast H rise. Several flares were observed in the 3835 band; such emission appears when the 5.1–6.6 keV flux exceeds 5 × 104 ph cm-2 s-1 at the Earth. Smaller flares produce no 3835 emission; we conclude that coronal back conduction cannot produce the bright chromospheric network of that wavelength.The nearly simultaneous growth of H emission at distant points means an agent travelling faster than 5 × 103 km s-1 is responsible, presumably electrons.In all cases near the limb an elevated Ha source is seen with the same time duration as HXR flux; it is concluded that this H source is almost always an elevated cloud which is excited by the fast electrons. A rough calculation is given. Another calculation of H emission from compressed coronal material shows it to be inadequate.In several cases homologous flares occur within hours with the same X-ray properties.Radio models fit, more or less, with field strengths on the order of 100G. A number of flares are discussed in detail. 相似文献
5.
P. S. Goraya 《Astrophysics and Space Science》1981,78(2):419-425
The photoelectric spectrophotometric scans of the Be stars Gem, Ori, Mon and CMa have been analyzed to find out few stellar parameters. The absolute energy distributions of these stars in the wavelength range 350–750 nm have been given. Their effective temperatures and gravities have been estimated from comparisons with non-LTE model atmospheres. The stars Gem and Mon have been found to have Balmer discontinuities in emission. The excess emission in the region 620–750 nm has been observed for Mon and CMa. The evolutionary aspects of these stars are discussed and their masses have been estimated. 相似文献
6.
The problem of stability of the equilibrium points (the libration points) in the problem of motion of a mass point in the neighbourhood of a rotating triaxial ellipsoid is investigated in the strict sense.In the plane of parameters, depending on the form and dynamical characteristics of the ellipsoids, the regions of stability and instability of the libration points are obtained.It is shown that the libration points of the ellipsoids, the form and dynamical characteristics of which are close to the planets of the solar system, are stable.
( ) . , , . , , , .相似文献
7.
А. П. Маркеев 《Celestial Mechanics and Dynamical Astronomy》1973,8(2):307-322
. . ,e, , . . e, . , .
Stability of the librational triangular points of the three-dimensional elliptic restricted three-body problem is studied. The problem is solved in the non-linear statement at the small values of eccentricity.For all values ofe, , besides ones which correspond to the resonances of the third and the fourth order the librational points are stable taking into account the terms up to the fourth order in the normal form of the Hamiltonian function of the perturbed motion.At sufficiently smalle and the non-stability in sense of Liapunov has been proved. The approximate equations of the boundary of the stability area in the planee, has been obtained. The cause of the non-stability is an equality of the rotational period of the principal attracting masses in the elliptic orbit and the period of oscillation of indefinitely small mass along the direction perpendicular to the plane of their motion.相似文献
8.
, , , , . , , . , , - - ( , ..). - . 相似文献
9.
It is shown theoretically that the emission efficiency of amorphous grains with radii smaller than 100 Å has a -1-dependence in the wavelength region longer than 100 , whereas those of crystalline, metallic, and larger amorphous grains are proportional to -2 in far infrared. Astrophysical implications of the amorphous grains are discussed. 相似文献
10.
An essential part in the mechanics under study is taking into consideration the effect of motions of the Universe objects upon that of an individual one surrounded by them including those infinitely far from it. Only macro-objects of the Universe are meant here.
Zusammenfassung Ein wesentlicher Bestandteil der Mechanik unter unserer Betrachtung ist die Berechnung des Einflusses auf die Bewegung eines individuellen Objektes von Bewegungen der Universum Objekte die es umringen einschließlich jene Objekte, die unendlich entfernt sind. Nur Makroobjekte des Weltalles sind in der Absicht dabei.
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11.
Г. А. ГурзадЯн 《Astrophysics and Space Science》1979,62(1):55-66
, oqn ANS (1500–3300 Å) , I , 3–15 . , <2000 Å nepexo , 1.5 MB . 0 , . . 相似文献
12.
13.
14.
Л. С. Бисноватыйколан В. С. ИмШенник Д. К. Надежин В. М. Чечеткин 《Astrophysics and Space Science》1975,35(1):3-21
qp qz : (1) -, qi , (2) - (R=0.01–0.1R
) (3) - . qs. (1) - 0.1 10–4
cm
–2, . - . (2) 108 . . 1042–43 , (25 ). 10% - (0.1 ). , , , , , . . (3) , , - . . (2×1041 ) (1021 ). - 1038–1039 , 0.25 . , , qq . - , , .
The following three mechanisms of generation of gamma-ray bursts at advanced phases of stellar evolution are considered; (1) gamma-ray bursts as a result of absorption of neutrino propagating through the envelope of a collapsing star, (2) gamma-ray burst due to thermal radiation of external layers of a compact star (R=0.01–0.1R ) heated by powerful shock wave, and (3) gamma-ray burst as a consequence of possible ejection of matter from neutron star at some active phases of its evolution. In the case (1) the gamma-ray flux at the top of the Earth's atmosphere is about 10–4 (0.1 MeV photons) cm–2, if a collapsing star is at Galactic distance (10 kpc). It is considerably less than observed one. The observations of such gamma-bursts however would be an important supplement to the direct detection of neutrino radiation from collapsing stars. In the case (2) external layers of a star are heated up to 108 K. As a result we have a short pulse of thermal radiation with total energy of the order of 1042–43 erg. The main fraction of the radiation is in the X-ray ( 25 keV), about 10% of total energy being radiated in gamma-ray ( 0.1 MeV). The energy of such a burst is sufficient for explaining observed gamma-bursts provided the supernova outburst probably takes place in our Galaxy and as a result we have some trouble with explanation of observed frequency and spectra of gammabursts. In the case (3) ejection from neutron star of chemically nonequilibrium matter results in the intensive gamma-radiation in consequence of superheavy nuclei fission followed by beta-decays and radiative captures of free neutrons. The ejection of matter from neutron stars may be connected with observed jumps of pulsar's periods. The total ejected mass ( 1021 g) can be evaluated from increase of kinetic energy ( 2×1041 erg.) of Crab nebula filaments. The resulting theoretical energy of gammabursts is of the order of 1038–39 erg. It is in accordance with observations provided the mean distance of gamma-ray sources is about 0.25 kpc. Contrary to the supernova-outburst mechanism in this case we have probably no troubles with frequency and spectra of gamma-bursts. Among the three mechanisms considered above ejection of matter from neutron stars seems to be a more suitable one for explanation of observations.相似文献
15.
, . () . , , , . ( ), , , . . (2.7). ( 1 k
1 ,V — , — .) (k
1) (k) §2 ( (2.14)). , (3.6) (3.4), (3.8) . (3.9)–(3.13) ( (3.9), (3.10) (3.11) , (3.12)–(3.13) ). (3.14), (3.16)–(3.19). - . (3.15). ( (4.14)–(4.15)). (4.23)–(4.25). (4.26)–(4.28). §5. , . ((5.5)–(5.6)). , . (5.10) . 相似文献
16.
G. A. Krasinsky 《Celestial Mechanics and Dynamical Astronomy》1972,6(1):60-83
The general conception of the critical inclinations and eccentricities for theN-planet problem is introduced. The connection of this conception with the existence and stability of particular solutions is established. In the restricted circular problem of three bodies the existence of the critical inclinations is proved for any values of the ratio of semiaxes . The asymptotic behaviour of the critical inclinations as 1 is investigated.
. . . 1.相似文献
17.
- . , - . -. 相似文献
18.
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19.
Constantin Kholchevnikov 《Celestial Mechanics and Dynamical Astronomy》1971,3(2):232-240
The potential of a body of revolution is expanded in a series of spherical functions. It is proved that, for a body with analytical density limited by an analytical surface the coefficients of expansion decrease in geometrical progression.
. , , , .相似文献
20.
В. А. Гаген-Торн 《Astrophysics and Space Science》1980,73(2):279-294
J 287 1972–1976. , . . J ( ), () . (0=80°) . J 287 ¶ . p=42.8%, 0=101°. (50%). 相似文献