共查询到20条相似文献，搜索用时 31 毫秒
1.
Possible solar neutron emission associated with five SMM gamma-ray events on 7 June 1980, 21 June 1980, 6 November 1980, 26 November 1982 and 25 April 1984 was found from analysis of 10-minute records of the ground-based neutron monitor at Tokyo. Of these the two events on 21 June 1980 and 25 April 1984 have been already known as neutron events. The time histories of the neutron monitor count rate are compared with those of the gamma-ray count rate and the possibility of energetic neutron emission at the flare site is discussed. 相似文献
2.
B. V. Jackson 《Solar physics》1985,100(1-2):563-574
The zodiacal light photometers on board the HELIOS spacecraft can be used to form images of coronal mass ejections in the interplanetary medium. Several aspects of these data are unique: they trace coronal mass ejections using Thomson scattering techniques to distances from the Sun greater than 0.5 AU; their perspective from the HELIOS orbits allow information to be gained about the three-dimensional shapes of specific mass ejections viewed both by coronagraphs and HELIOS; the global view afforded by the spacecrafts photometers can image the mass ejection from within and thus relate in situ measurements to the shape of the whole structure. To date, the HELIOS photometers have been used to study coronagraph-observed mass ejections including those which originate at the Sun on 7 May, 24 May, and 27 November, 1979, and 21 May, 18 June, 29 June, and 6 November, 1980. Masses of ejections determined from these data are generally a few times larger than masses determined from SOLWIND coronagraph images. 相似文献
3.
Solar flare gamma-ray emissions from energetic ions and electrons have been detected and measured to GeV energies since 1980. In addition, neutrons produced in solar flares with 100 MeV to GeV energies have been observed at the Earth. These emis-sions are produced by the highest energy ions and electrons accelerated at the Sun and they provide our only direct (albeit secondary) knowledge about the properties of the acceler-ator(s) acting in a solar flare. The solar flares, which have direct evidence for pion-decaygamma-rays, are unique and are the focus of this paper. We review our current knowl-edge of the highest energy solar emissions, and how the characteristics of the acceleration process are deduced from the observations. Results from the RHESSI, INTEGRAL and CORONAS missions will also be covered. The review will also cover the solar flare ca-pabilities of the new mission, FERMI GAMMA RAY SPACE TELESCOPE, launched on 2008 June 11. Finally, we discuss the requirements for future missions to advance this vital area of solar flare physics. 相似文献
4.
A. Cassatella F. A. Córdova M. Friedjung J. Kenyon L. Piro R. Viotti 《Astrophysics and Space Science》1987,131(1-2):763-763
We describe the first X-ray monitoring of a symbiotic star during phases of enhanced activity. AG Dra is a Pop II object with a composite spectrum, characterized by a cool K-type component, prominent high ionization emission lines and a strong UV continuum which is attributed to a hot dwarf companion. Periodic variability of the UV radiation during minimum could be attributed to the orbital motion of the system. In April 1980 HEAO-2 detected an intense, soft X-ray flux from AG Dra, stronger than in other symbiotic stars. After one major outburst of November 1980, which continued until 1983, two more outbursts occurred in February 1985 and January 1986, and coordinated X-ray (EXOSAT) and ultraviolet (IUE) observations were organized to study the behaviour of AG Dra during different activity phases. EXOSAT observations made during decline after the 1985 outburst, revealed a weak X-ray flux in the Thin Lexan filter of the Low Energy dedtector. Observations made during minimum, in June and November 1985, at phases 0.22 and 0.50 of the UV light curve, disclosed the presence of an intense X-ray flux, which was not occulted in November. AG Dra was again observed with EXOSAT in February 1986 when the stellar luminosity was still at maximum. No X-ray flux was detected, in spite of the prominent, high ionization UV spectrum observed with IUE.A detailed discussion of the X-ray and ultraviolet results on AG Dra in the light of possible models is in progress.Paper presented at the IAU Colloquium No. 93 on Cataclysmic Variables. Recent Multi-Frequency Observations and Theoretical Developments, held at Dr. Remeis-Sternwarte Bamberg, F.R.G., 16–19 June, 1986. 相似文献
5.
Byurakan Astrophysical Observatory. Translated from Astrofizika, Vol. 34, No. 3, pp. 449–457, May–June, 1991. 相似文献
6.
X-ray and ultraviolet observations from SMM of a filament-associated event on 22 November, 1980 are examined in conjunction with ground-based optical observations, in order to determine the magnetic field configuration involved in the flaring process. We find evidence that the flare was produced by gradual energy release in a large sheared magnetic loop which interacted with another smaller loop. Non-thermal processes, as indicated by hard X-ray emission and impulsive UV kernels, were produced in the interaction of the two loops. Although this flare shared some of the characteristics of Long Duration (class II) Events, we found no indication of a helmet-type configuration, as generally envisaged for class II events. On the contrary, the magnetic configuration of the 22 November, 1980 event was more similar to that of a compact (class I) flare, although on a much larger spatial scale and longer time scale. 相似文献
7.
G. Srinivasan 《Astronomy and Astrophysics Review》2002,11(1):67-96
Summary. The maximum mass of neutron stars plays an important role in determining the end point of the evolution of massive stars.
As the number of stellar mass black holes in binary x-ray sources grows, and as the mass spectrum of the black holes emerges,
the value of the maximum mass of neutron stars has acquired great significance. Although it is now more than sixty years since
the first attempt by Oppenheimer and Volkoff, no definitive answer can be given. This review will attempt to outline the main
difficulties, both conceptual as well as technical, that stand in the way of a reliable estimate of the maximum mass. We shall
also highlight how laboratory experiments, as well as astronomical observations, may help to clarify the true nature of the
interior of neutron stars.
Received 26 November 2001 / Published online 22 April 2002 相似文献
8.
M. V. Hayrapetyan 《Astrophysics》2008,51(4):559-564
The gravitational radiation of a neutron star with a weakly coupled superfluid component is considered. It is assumed that
regions can exist in the star's core which rotate at substantially higher angular velocities than the observed angular velocities
of pulsars. A star of this sort has a quadrupole moment on the order of the maximum value for the neutron star configurations
that have been discussed, so it could be a powerful source of gravitational radiation for the planned Advanced LIGO detector.
Translated from Astrofizika, Vol. 51, No. 4, pp. 647–652 (November 2008). 相似文献
9.
L. N. Volvach A. A. Berezhnoi A. E. Volvach 《Bulletin of the Crimean Astrophysical Observatory》2013,109(1):71-75
The observation results for comets C/2009 R1 (McNaught) (June 14–28, 2010) and 17P/Holmes (November 25–December 3, 2007) performed in the line of the OH molecule and at a wavelength of 18 cm are presented. The gas productivity of the OH molecule for comet C/2009 R1 (McNaught) (June 14–28, 2010) as a function of the heliocentric distance (0.42–0.62 au) is determined. 相似文献
10.
Simultaneous observations by the ESA satellite COS-B show that the 2–12 keV X-rays and 150–5000 MeV gamma-rays of Cyg X-3 are negatively correlated. A clear gamma-ray image of Cyg X-3 can be obtained between June 1977 and June 1980, when the X-ray emission was low, to yield a flux of P(E > 100MeV) ~ 1 × 10−6cm−2s−1. 相似文献
11.
Shortly after the dynamic flare of 14 44 UT on 6 November, 1980, which initiated the second revival in the sequence of post-flare coronal arches of 6–7 November, a moving thermal disturbance was observed in the fine field of view of HXIS. From 15 40 UT until about 18 UT, when it left the field of view, the disturbance rose into the corona, as indicated by a projected velocity of 7.4 km s-1 in the south-east direction. The feature was located above the reconnection region of the dynamic flare and was apparently related to the revived coronal arch. Observations in the coarse field of view after 18 UT revealed a temperature maximum in the revived arch, rising with a velocity of 7.0 km s-1 directly in continuation of the thermal disturbance. The rise velocity of the disturbance was initially (at least until 17 20 UT) very similar to the rise velocities observed for the post-flare loop tops of the parent flare. This suggests that the rise of the reconnection point, in the Kopp and Pneuman (1976) mechanism responsible for the rise of the loop tops, also dictates the rise of the disturbance. From energy requirements it follows that in this phase the disturbed region is still a separate magnetic island, thermally isolated from the old arch structure and the post-flare loops. After 18 UT the rise of the post-flare loop tops slowed down to 2 km s-1, which is significantly slower than the rise of the brightness and temperature maxima of the revived arch in the coarse field of view. Thus in this phase the Kopp and Pneuman mechanism is no longer directly responsible for the rise of the thermal structure and the rise possibly reflects the merging of the old and the new arch structures.A similar thermal disturbance was observed after the dynamic flare of 07: 53 UT on 4 June, 1980. On the other hand, the confined flare of 17 25 UT on 6 November, 1980, did not show this phenomenon. Apparently this type of disturbance occurs after dynamic flares only, in particular when the flare is associated with an arch revival. 相似文献
12.
A spectrum of Triton between 6000 and 9000 Å was recorded in June 1980 at the ESO 1.52-m telescope in La Silla. From these data, an upper limit of 3.5 m-am is derived for the CH4 gaseous abundance on Triton. 相似文献
13.
Giant arches, first detected by the HXIS instrument aboard SMM, are still a poorly understood component of the flare scenario. Their origin remains uncertain and their behavior, quite different in separate events, has not yet been satisfactorily explained. The purpose of the present paper is to analyze the giant arches imaged on November 6–7, 1980, which, in contrast to that observed on May 21, 1980, were not stationary and had shorter cooling times. In particular, we use a procedure, already applied to the May 21 case, to compute the three-dimensional topology of the magnetic field which forms by reconnection over the active region containing the November arches. This technique allows us to verify that the observed structures are aligned with the computed field lines, lending support to the hypothesis that they originate through a reconnection process which occurs at progressively larger altitudes. Moreover, a calculation of the magnetic energy liberated by reconnection shows that enough energy may be thereby released to account for the observed thermal energy enhancement of the HXIS arches. Finally, the lifetime of the features is shown to be consistent with that predicted by cooling via radiation and field-aligned conduction to the underlying chromosphere. 相似文献
14.
Evolutionary calculations based on realistic equations of state indicate the stratified nature of the distribution of hadron
matter in the interiors of neutron stars. In the proposed model, the stratified structure of a neutron star is treated as
a rigid inert core surrounded by a dynamical layer. The physical basis for the model is the concept of the stellar matter
of the peripheral envelope as an elastic Fermi continuum, the motions of which are described by the equations of nuclear elastodynamics,
proposed in the macroscopic theory of collective processes in laboratory nuclear physics. It is shown that the vibrational
dynamics of a neutron star is characterized by two branches of gravitational—elastic, spheroidal (s-mode) and torsional (t-mode)
nonradial eigenvibrations. Estimates obtained for the periods of global, gravitational nonradial modes suggest that variations
in the intensity of micropulses observed in the millisecond range of the spectra of C-pulsars may be ascribed to these vibrations.
The proposed two-component model of a neutron star enables one to consider a glitch in a pulsar’s radio emission as a starquake
due to the passage of the companion through periastron of the binary system.
Translated from Astrofizika, Vol. 42, No. 2, pp. 235–252, April–June, 1999 相似文献
15.
The Ginzburg-Landau equations are derived for the magnetic and gluomagnetic gauge fields of nonabelian semi-superfluid vortex
filaments in color superconducting cores of neutron stars containing a diquark CFL condensate. The interaction of the diquark
CFL condensate with the magnetic and gluomagnetic gauge fields is taken into account. The asymptotic values of the energies
of these filaments are determined from the quantization conditions. It is shown that a lattice of semi-superfluid vortex filaments
with a minimal quantum of circulation develops in the quark superconducting core during rotation of the star. The magnetic
field in the core of this vortex is on the order of 1018 G. A cluster of proton vortices, which develops in the hadron phase surrounding every superfluid neutron vortex owing to
an entrainment effect, creates new semi-superfluid vortex filaments with a minimal quantum of circulation in the quark superconducting
core.
Translated from Astrofizika, Vol. 51, No. 4, pp. 633–646 (November 2008). 相似文献
16.
IUE observations of the hydrogen-deficient irregular variable star MV Sgr obtained in 1980 June-October and also in 1979 November
are discussed. These observations show a prominent λ 2200 absorption feature. A value ofE(B — V) = 0.55 is deduced from the strength of λ 2200 band assuming that this absorption is caused by interstellar medium. The dereddened
continuum obtained at different times can be fitted to a theoretical energy distribution of a helium star model with Teff = 18000 K and log g = 2.5, similar to that of BD + 10‡ 2179. This theoretical energy distribution, after applying interstellar extinction, givesV = 12.7 mag, agreeing with the observed visual magnitude of ≃ 13 in 1979 November and 1980 June-October. Even though there
was no change in the continuum flux, the ultraviolet line-spectrum shows variations. The IUE spectra of 1980 October show
enhanced (circumstellar) absorption lines of Fe II, Si II, O I, C I and others along with the absorption lines of a B star.
In view of the similarity of the spectroscopic phenomena of MV Sgr with that of α Sco system, a model is proposed in which
a cool companion star, surrounded by dust, occasionally blows gas towards the hotter hydrogen-poor B star. This model explains
the irregular light variations and the spectroscopic phenomena.
Based on observations obtained with IUE satellite at the Villafranca Satellite Tracking Station of the European Space Agency. 相似文献
17.
The solar soft X-ray (XUV) radiation is important for upper atmosphere studies as it is one of the primary energy inputs and
is highly variable. The XUV Photometer System (XPS) aboard the Solar Radiation and Climate Experiment (SORCE) has been measuring
the solar XUV irradiance since March 2003 with a time cadence of 10 s and with about 70% duty cycle. The XPS measurements
are between 0.1 and 34 nm and additionally the bright hydrogen emission at 121.6 nm. The XUV radiation varies by a factor
of ∼2 with a period of ∼27 days that is due to the modulation of the active regions on the rotating Sun. The SORCE mission
has observed over 20 solar rotations during the declining phase of solar cycle 23. The solar XUV irradiance also varies by
more than a factor of 10 during the large X-class flares observed during the May–June 2003, October–November 2003, and July
2004 solar storm periods. There were 7 large X-class flares during the May–June 2003 storm period, 11 X-class flares during
the October–November 2003 storm period, and 6 X-class flares during the July 2004 storm period. The X28 flare on 4 November
2003 is the largest flare since GOES began its solar X-ray measurements in 1976. The XUV variations during the X-class flares
are as large as the expected solar cycle variations. 相似文献
18.
It is shown that knowing the energy flux density of the radio emission, the rate of increase in the period, and the distance
of a pulsar enables one to calculate all the rest of its most important characteristics (the solid angle of the radio emission
beam, the radio luminosity, the solid angle of the beam of γ rays, the energy flux density of the g-ray emission, and the
magnetic moment, moment of inertia, and mass of the neutron star). Equations from which these pulsar characteristics can be
calculated are given at the end of the paper. The results of calculations for a number of pulsars are given in Tables 2 and
3 as an illustration.
Translated from Astrofizika, Vol. 43, No. 2, pp. 277-291, April–June, 2000. 相似文献
19.
Results of neutral air density, temperature and pressure measurements obtained between November 1968 and June 1972 in the height range between 80 and 95 km over Arenosillo, Spain are given. A simple foil cloud payload, primarily designed for wind finding purposes, was used. The results obtained are compared with CIRA Standard Atmosphere data and ground based radio wave absorption measurements. An estimate of the accuracy of the method is given. 相似文献
20.
The cyclical behaviors of sunspots,flares and coronal mass ejections(CMEs) for 54 months from 2008 November to 2013 April after the onset of Solar Cycle(SC) 24 are compared,for the first time,with those of SC 23 from 1996 November to 2001 April.The results are summarized below.(i) During the maximum phase,the number of sunspots in SC 24 is significantly smaller than that for SC 23 and the number of flares in SC 24 is comparable to that of SC 23.(ii) The number of CMEs in SC 24 is larger than that in SC 23 and the speed of CMEs in SC 24 is smaller than that of SC 23 during the maximum phase.We individually survey all the CMEs(1647 CMEs) from 2010 June to 2011 June.A total of 161 CMEs associated with solar surface activity events can be identified.About 45%of CMEs are associated with quiescent prominence eruptions,27%of CMEs only with solar flares,19%of CMEs with both active-region prominence eruptions and solar flares,and 9%of CMEs only with active-region prominence eruptions.Comparing the association of the CMEs and their source regions in SC 24 with that in SC 23,we notice that the characteristics of source regions for CMEs during SC 24 may be different from those of SC 23. 相似文献