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Showing papers in "Astrophysics and Space Science in 1977"


Journal ArticleDOI
TL;DR: In this paper, a model of the solar nebula is constructed by adding the solar complement of light elements to each planet, using recent models of planetary compositions, and uncertainties in this approach are estimated.
Abstract: A model ‘solar nebula’ is constructed by adding the solar complement of light elements to each planet, using recent models of planetary compositions. Uncertainties in this approach are estimated. The computed surface density varies approximately asr −3/2. Mercury, Mars and the asteroid belt are anomalously low in mass, but processes exist which would preferentially remove matter from these regions. Planetary masses and compositions are generally consistent with a monotonic density distribution in the primordial solar nebula.

1,010 citations


Journal ArticleDOI
TL;DR: In this article, a method of determination of parameter sets characterizing models of starspots is described, which makes use of a systematic integral notation in the description of the darkening due to spots and optimization procedures to evaluate appropriate parameters.
Abstract: A method of determination of parameter sets characterizing models of starspots is described. The method makes use of a systematic integral notation in the description of the darkening due to spots and optimization procedures to evaluate appropriate parameters. The method is applied to light curves of YY Gem and CC Eri. In the latter case a comparison is made with the results of Bopp and Evans's (1973) study. The physical meaning of the derived parameter set and possibly correlated effects are considered for YY Gem.

109 citations


Journal ArticleDOI
TL;DR: In this paper, the authors derived the effective dielectric function of a composite medium consisting of small spherical inclusions embedded in a homogeneous matrix and showed that the validity of the theory does not depend on the matrix being nonabsorbing.
Abstract: The Maxwell-Garnet (MG) expression for the effective dielectric function of a composite medium consisting of small spherical inclusions embedded in a homogeneous matrix is derived. It is shown that the MG theory accounts for dipole-dipole interactions among the inclusions and that the validity of the theory does not depend on the matrix being non-absorbing. Moreover, by comparing the Mie theory with the MG theory it is shown that the MG dielectric function is correct at least to terms linear in the volume fraction of inclusions. For a sphere ‘carved out’ of such a medium we then have a prescription for calculating cross sections and scattering phase functions. The scattering properties of a small heterogeneous sphere described by the MG dielectric function are identical to those of a small layered sphere with the same outer radius and volumes of the two constituents. In the small particle (Rayleigh) limit we discuss two illustrative examples: (a) a porous sphere, (b) spherical inclusions in a ‘waxy’ dielectric matrix. In both cases we obtain the conditions for resonance absorption. Finally, we apply these results to evaluate the role of porosity in individual graphite grains, and of a waxy matrix containing small spherical graphite inclusion, on the graphite particle resonance absorption at 2200 A. Increasing porosity and increasing the volume fraction of matrix material have similar effects in shifting the resonance to longer wavelengths.

63 citations


Journal ArticleDOI
TL;DR: In this article, it was shown that the eigenvalue sum for the cosmic-ray spatial diffusion coefficient parallel to the mean magnetic field is precisely equivalent to the time integral of the particle-velocity correlation function parallel to a mean field.
Abstract: It is shown that Earl's (1973) eigenvalue sum for the cosmic-ray spatial diffusion coefficient parallel to the mean magnetic field is precisely equivalent to the time integral of the particle-velocity correlation function parallel to the mean field. A derivation due to Kubo (1957) is applied to cosmic-ray pitch-angle scattering, and it is proven that all nine components of the cosmic-ray diffusion tensor can be expressed as integrals over the velocity correlation function. A pitch-angle correlation function is derived, and the effect of long-wavelength turbulence on the velocity correlation function and spatial diffusion coefficients is examined. Application of the velocity-correlation method to a realistic case involving both pitch-angle scattering and appreciable fluctuation in the direction of the local field indicates that long-wavelength turbulence in the local field reduces the parallel diffusion coefficient and places an upper limit on the ratio of the perpendicular to parallel diffusion coefficients.

53 citations


Journal ArticleDOI
TL;DR: In this paper, a model of the formation of molecules by surface reactions on interstellar grains is described and assessed numerically, and the model predicts that for the molecules, other than H2, likely to be important in the interstellar medium, the formation rates by surface reaction are insensitive to the nature of the surface.
Abstract: A model of the formation of molecules by surface reactions on interstellar grains is described and assessed numerically. The model predicts that for the molecules—other than H2-likely to be important in the interstellar medium, the formation rates by surface reactions are insensitive to the nature of the surface. The formation rates have magnitudes which are significant when compared with other routes. The model also describes H2 formation in high density clouds and shows it to be parameter dependent.

52 citations


Journal ArticleDOI
TL;DR: In this article, a simple model of cosmic ray propagation is proposed from which the major experimental results can be derived: the model reproduces the observed nuclear abundances and accounts for the observed changes of nuclear composition with energy.
Abstract: A simple model of cosmic ray propagation is proposed from which the major experimental results can be derived: The model reproduces the observed nuclear abundances and accounts for the observed changes of nuclear composition with energy, the high degree of isotropy of cosmic ray flux at all energies, and the high degree of its constancy throughout the history of the Solar System. It is consistent with the observed size distribution of extensive airshowers, the intensity and energy distribution of the electron component, and the diffuse emission of γ-rays and radio waves. The model is characterized by the two basic assumptions: (1) that cosmic rays have been injected at an unchanging rate by sources located in the galactic spiral arms and (2) that a large-scale magnetic field retains all particles in our galaxy, where they interact with interstellar gas, so that all complex nuclei are finally fragmented and their energy dissipated in meson production and electro-magnetic interactions.

48 citations


Journal ArticleDOI
TL;DR: In this article, the collapse of an iron-oxygen star with masses of 2M has been studied, and it is shown that the collapse proceeds in consequence of intensive energy losses due to neutrino volume radiation.
Abstract: The collapse of iron-oxygen stars with masses of 2M⊙ has been calculated. The commencement of the collapse is due to dissociation of iron-group nuclei into free nucleons. After a while, the collapse proceeds in consequence of intensive energy losses due to neutrino volume radiation. At an intermediate stage of the collapse, the core — opaque with respect to neutrino radiation (neutrino core) — is formed inside the collapsing star. Both the gradual increase of the mass of the neutrino core and the partial absorption of neutrinos radiated from the surface of the neutrino core by the stellar envelope (deposition) were taken into account in our calculations. The kinetics of oxygen burning in the outer layers of the envelope was also allowed for. Neither the deposition, nor the oxygen burning, result in ejection of stellar envelopes.

46 citations


Journal ArticleDOI
TL;DR: In this paper, the fractional loss of light αl0 of arbitrarily limb-darkened stars in the form of Hankel transforms of zero order is evaluated in terms of expansions that converge under all circumstances envisaged.
Abstract: The aim of the present paper will be to make use of the expressions, established in Paper XI, for the fractional loss of light αl0 of arbitrarily limb-darkened stars in the form of Hankel transforms of zero order, in order to evaluate the explicit forms of the αl0's for different types of eclipses (Section 2), as well as of the momentsA2mof the respective light curves (Section 3)-in a closed form; or in terms of expansions that converge under all circumstances envisaged. Particular attention will be directed to a connection between these expansions and other functions already available in tabular form; or to alternative forms amenable to automatic computation.

46 citations


Journal ArticleDOI
I. H. Urch1
TL;DR: In this article, the diffusion of charged particles in a static turbulent magnetic field, which is superimposed on a constant magnetic fieldB 0k, is considered and a new relationship between the particle flux and the particle number density is found.
Abstract: The diffusion of charged particles in a static turbulent magnetic field, which is superimposed on a constant magnetic fieldB0k, is considered. Previous calculations of the particle flux in a direction perpendicular tok have related the fluxS⊥ to the particle number densityf byS⊥ = − κ⊥(▽f)⊥ where κ⊥ is found from the power spectrum of the turbulent magnetic field. It is shown that this formula is inconsistent with the notion, developed by Jokipii and Parker (1969), that the perpendicular particle flux primarily arises because of random-walking of magnetic field lines across the directionk. For a simple example of a turbulent magnetic field it is shown that the above expression forS⊥ is incorrect; the particle fluxS⊥ is recalculated and a new relationship betweenS⊥ andf is found. This new expression forS⊥ is shown to be consistent with particle diffusion across the directionk being due to random-walking of the magnetic field lines.

42 citations


Journal ArticleDOI
TL;DR: In this paper, a statement of the problem of gravitational collapse and a computational method are described, where the main feature of the collapse is its extremely high heterogeneity, and the increase of the mass of the core which is opaque with respect to neutrino radiation is fully taken into account in the calculations of the gravitational collapse.
Abstract: A statement of the problem of gravitational collapse and a computational method are described. The main feature of the collapse — its extremely high heterogeneity — is taken into account. The structure of a collapsing star is characterized by a dense and hot nucleon core which is opaque with respect to neutrino radiation and is embedded in to and extended envelope, almost transparent to neutrinos. The envelope is gradually being accreted onto the core. The enormous amount of energy, radiated in the form of neutrinos and antineutrinos, make us pay particular attention to relatively small absorption of neutrino radiation by extended envelope (so-called energy of deposition). The inclusion of the energy deposition in the calculations is of importance for the problem of transformation of an implosion into an explosion. The deposition is taken into consideration in the approximation of diluted neutrino radiation which escapes from neutrino photosphere and is partially absorbed in the envelope. Both the generation of energy due to deposition and the change of neutronto-proton ratio are taken into account. The increase of the mass of the core, which is opaque with respect to neutrino radiation, is fully taken into account in the calculations of the gravitational collapse.

40 citations


Journal ArticleDOI
TL;DR: In this paper, it is shown that the Earth's atmosphere is of primary origin, forming as an immediate and necessary consequence of the final stages of planetary accretion, and that once the planetary embryo reached a critical size, the impacting material began to vaporize.
Abstract: It is generally supposed that the atmospheres of the terrestrial planets were formed by secondary degassing processes. We propose, instead, that they are of primary origin, forming as an immediate and necessary consequence of the final stages of planetary accretion. Once the planetary embryo reached a critical size, the impacting material began to vaporize. The atmosphere, so created, then decelerated other impacting material, thus limiting the rate of atmospheric growth. We show that, given reasonable assumptions concerning the chemical composition of the impacting material, an acceptable model for the early atmosphere of the Earth, and the present atmospheres of Venus and Mars results.

Journal ArticleDOI
TL;DR: In this article, the authors introduced a new definition of the loss of light suffered by mutual eclipses of the components of close binary systems, namely, as across-correlation of two apertures representing the eclipsing and eclipsed discs.
Abstract: The aim of the present paper will be to introduce a new definition of the loss of light suffered by mutual eclipses of the components of close binary systems: namely, as across-correlation of two apertures representing the eclipsing and eclipsed discs.

Journal ArticleDOI
TL;DR: In this article, the dynamic spectra of S-bursts were observed with sweep-frequency and multi-channel receivers operating at frequency ranges 21-30 and 20.20 MHz, respectively.
Abstract: Dynamic spectra of Jupiter's S-bursts are observed with sweep-frequency and multi-channel receivers operating at frequency ranges 21–30 and 20.85–23.20 MHz, respectively. Spectra obtained with time resolutions of 0.2, 0.02, and 0.004 s are compared, the frequency resolution being 50 kHz. The most normal appearance of S-bursts is in trains with a frequency range of the order of 1 MHz. Narrow-band Strains also occur. Narrow-band L-emissions in region B are often associated with S-bursts, obviously in the manner described by Flagget al. (1976). Synoptic spectral observations indicate that region B for S-bursts exhibits a drift in longitude similar to that for L-bursts. The Io phase profile for S-bursts has a maximum in the vicinity of 80° in region B and 230° in region C. S-bursts observed in 1976 have higher drift rates than those compiled by Krauscheet al. (1976). Region C bursts have simpler spectra and lower drift rates than region B bursts.

Journal ArticleDOI
TL;DR: In this paper, the energy spectra of cosmic ray nuclei in the charge range 5≤Z≤26 have been derived from the response of an acrylic plastic Cerenkov detector.
Abstract: Energy spectra of cosmic ray nuclei in the charge range 5≤Z≤26 have been derived from the response of an acrylic plastic Cerenkov detector. Data were obtained using a balloon-borne detector and cover the energy range 320≲E≲2200 MeV amu−1. Spectra are derived from a formal deconvolution using the method of Lezniak (1975). Relative spectra of different elements are compared by observing the charge ratios. Secondary-primary ratios are observed to decrease with increasing energy, consistent with the effect previously observed at higher energy. Primary-to-primary ratios are constant for 6≤Z≤10 and 14≤Z≤26 but vary for 10≤Z≤14. This data is found to be consistent with existing data, where comparable, and lends strong support to the idea of two separate source populations contributing to the cosmic ray composition.

Journal ArticleDOI
TL;DR: In this paper, a new representation of Chandrasekhar's H-functions corresponding to the dispersion function was obtained in the form of a Fredholm type integral equation, which has proved to be very useful in solving coupled integral equations involving X-,Y -functions of transport problems; a closed form approximation ofH(z) to a sufficiently high degree of accuracy is then readily available by term integrations.
Abstract: We obtain a new representation of Chandrasekhar'sH-functionsH(z) corresponding to the dispersion functionT(z) = |δ rs −f rs (z)|, [f rs (z)] is of rank one.H(z) is obtained in the form $$H\left( z \right) = \left( {A_0 + A_1 z} \right)/\left( {K + z} \right) - \sum\limits_1^n {\int\limits_{E_r } {P_r (x) dx/(x + z),} }$$ WhereP r x(=o r (x)/H(x)) is continuous onE r which are subsets of [0, 1].A o ,A 1 are determinable constants andK is the positive root ofT(z),o r (x) are known functions. From this formH(z) is then obtained in terms of a Fredholm type integral equation. This new form ofH(z) has proved to be very useful in solving coupled integral equations involvingX-,Y-functions of transport problems.P r(x) can be replaced by approximating polynomials whose coefficients can be determined as functions of the moments of known functions; a closed form approximation ofH(z) to a sufficiently high degree of accuracy is then readily available by term integrations.

Journal ArticleDOI
TL;DR: In this article, the linear adiabatic oscillations of a spherically symmetric star are analyzed in terms of potential fields, and it is found that all displacement fields ϱξ can be described as either spheroidal or toroidal fields.
Abstract: The linear adiabatic oscillations of a spherically symmetric star are analyzed in terms of potential fields. It is found that all displacement fields ϱξ can be described as either spheroidal or toroidal fields.

Journal ArticleDOI
TL;DR: In this paper, the electron cap shape of a rapidly rotating neutron star with a strong magnetic field has been provided, where the magnetic dipole axis is aligned, and ejection of positive charged particles from the star's surface absent.
Abstract: Numerical calculations of the electron cap shape of a rapidly rotating neutron star with a strong magnetic field have been provided. It is supposed that the magnetic dipole axis is aligned, and ejection of positive charged particles from the star's surface absent. The total charge of the star has been calculated. Estimation of the character of charged-particle motion in the electromagnetic field of the star has been obtained. It is shown that two streams of charged particles escape from the star surface. The electron stream moves along the magnetic axis. The electron stream is enveloped by proton-positron stream, which is generated by returning hard electrons accelerated by electromagnetic field of the star.

Journal ArticleDOI
TL;DR: In this paper, the problem of the quasi-steady matter-antimatter boundary layers discussed in Klein-Alfven's cosmological theory and a crude model of the corresponding ambiplasma balance is presented.
Abstract: This paper outlines the problems of the quasi-steady matter-antimatter boundary layers discussed in Klein-Alfven's cosmological theory, and a crude model of the corresponding ambiplasma balance is presented:

Journal ArticleDOI
TL;DR: In this paper, the authors established the explicit forms of the photometric perturbations, in the frequency-domain, of close binaries, whose components are distorted by axial rotation and mutual tidal action.
Abstract: The aim of the present paper is to establish the explicit forms of the photometric perturbations, in the frequency-domain, of close binaries, whose components are distorted by axial rotation and mutual tidal action. Following a brief introduction, Section 2 describes the light changes and the photometric perturbations within eclipses in the frequency-domain. In Section 3 the explicit forms of the perturbations for occultation eclipses terminating in totality are given; while in Section 4 analogous results are established for transit eclipses terminating in annular phases. In this latter case the results can be expressed in terms of the photometric perturbations for total eclipses and in terms of some series. To facilitate applications to actual stars these series have been computed and their results are represented in Table I and by the Graphs. Finally, Section 5 gives a discussion of the results. An extension of the photometric perturbations to the case of partial eclipses will be given in a subsequent communication.

Journal ArticleDOI
TL;DR: In this article, the final state of binary systems with initial massesM1i=10M to 15M was derived from the mass of their C/O-cores, and the possibility of a second stage of mass transfer towards the secondary was considered.
Abstract: The final state of the primaries of binary systems with initial massesM1i=10M⊙ to 15M⊙ is derived from the mass of their C/O-cores. The possibility of a second stage of mass transfer towards the secondary is considered. It turns out that the critical mass for the bifurcation is about 14M⊙: stars with larger masses in this range are the progenitors of neutron stars, while the lower mass stars are the ancestors of white dwarfs.

Journal ArticleDOI
TL;DR: In this article, the changes in different terms of the Fokker-Planck equation, which describes energetic particle propagation, were analyzed in a theoretical blast wave model, which incorporates the interaction with plane polarized Alfven waves.
Abstract: Energetic particles, ejected from the Sun during solar flare events, may encounter interplanetary plasma/field conditions, which deviate considerably from the quiet time values used normally to describe the particle propagation. This is due to the presence of a hydromagnetic shock, which is emitted from the Sun at the time of the explosion. In a theoretical blast wave model, which incorporates the interaction with plane polarized Alfven waves, we have analysed the changes in different terms of the Fokker-Planck equation, which describes energetic particle propagation. In this treatment, the shock influence on energy changes and on the transport coefficients are discussed.

Journal ArticleDOI
TL;DR: In this paper, a comparison of the equations for the magnetic field transfer and for the heat transfer by two-dimensional turbulent convection of a conducting compressible medium was made, and it was shown that magnetic field can be transported as a scalar admixture provided it is parallel to the convective rolls.
Abstract: A comparison of the equations for the magnetic field transfer and for the heat transfer by two-dimensional turbulent convection of a conducting compressible medium shows the magnetic field to be transported as a scalar admixture provided it is parallel to the convective rolls. At high magnetic Reynolds numbers the field strength in a convective zone varies proportionally to the density of the medium.

Journal ArticleDOI
TL;DR: In this article, some mechanisms which are expected to produce the growth of dust grains in the protosolar nebula are studied during the isothermal and the adiabatic phase of the gravitational collapse.
Abstract: Some mechanisms which are expected to produce the growth of dust grains in the protosolar nebula are studied during the isothermal and the adiabatic phase of the gravitational collapse.

Journal ArticleDOI
TL;DR: In this article, a set of gas phase reactions involving nitrogen-bearing molecules is linked to a simple model of grain surface reactions and calculations are performed attempting to simulate the nitrogen chemistry in interstellar clouds of low and high density.
Abstract: A fairly complete but limited set of gas phase reactions involving nitrogen-bearing molecules is linked to a simple model of grain surface reactions. Calculations are performed attempting to simulate the nitrogen chemistry in interstellar clouds of low and high density. While it appears probable that grain surface reactions contribute to the chemistry in both regimes, conclusive evidence awaits observational and theoretical developments.

Journal ArticleDOI
TL;DR: In this paper, the authors reviewed and discussed attractive features and difficulties of the most widely held concepts on the energy sources in quasars and active galactic nuclei (a supermassive rotating magnetoplasmic body, an accreting black hole, a compact star cluster).
Abstract: Attractive features and difficulties of the most widely held concepts on the energy sources in quasars and active galactic nuclei (a supermassive rotating magnetoplasmic body, an accreting black hole, a compact star cluster) are reviewed and discussed. In the light of the available data (particularly of recent results on the character of optical variability in a number of objects) models of a compact star cluster seem improbable. The concept of a magnetoid is less vulnerable, but the final choice between magnetoid and accreting black hole will be possible only after the details of these models have been thoroughly elaborated, and when new observational data become available.

Journal ArticleDOI
TL;DR: These calculations represent a first attempt to ascertain the outcome of evolution over several decades of mass previously unexplored, and may have some relevance to models of X-ray sources in globular clusters.
Abstract: The final dynamical collapse of oxygen cores of 103 and 104M⊙ which undergo the pair formation instability is computed. These cores are found to suffer complete collapse, presumably to form black holes, in contrast to cores of ∼ 100M⊙ which have previously been found to explode completely, leaving no remnant. These calculations represent a first attempt to ascertain the outcome of evolution over several decades of mass previously unexplored. The outcome may have some relevance to models of X-ray sources in globular clusters.

Journal ArticleDOI
TL;DR: In this article, it is suggested that a bright auroral display is a part of a magnetosphere-ionosphere current system which is fed by a charge-separation process in the outer magnetosphere (or the solar wind).
Abstract: On the basis of field and particle observations, it is suggested that a bright auroral display is a part of a magnetosphere-ionosphere current system which is fed by a charge-separation process in the outer magnetosphere (or the solar wind). The upward magnetic-field-aligned current is flowing out of the display, carried mainly by downflowing electrons from the hot-particle populations in the outer magnetosphere (the ambient cold electrons being depleted at high altitudes). As a result of the magnetic mirroring of these downflowing current carriers, a large potential drop is set up along the magnetic field, increasing both the number flux and the kinetic energy of precipitating electrons. It is found that this simple basic model, when combined with wave-particle interactions, may be able to explain a highly diversified selection of auroral particle observations. It may thus be possible to explain both ‘inverted-V’ events and auroral rays in terms of a static parallel electric field, and the electric field may be compatible with a strongly variable pitch-angle distribution of the precipitating electrons, including distributions peaked at 90° as well as 0°. This model may also provide a simple explanation of the simultaneous precipitation of electrons and collimated positive ions.

Journal ArticleDOI
TL;DR: In this paper, the authors used 21 cm line data and stellar data to study the spiral structure of the inner parts of the Galaxy and obtained a parameter η =τ(dV/dr) proportional to the mean densities using a first approximation for the velocity gradients due to differential rotation.
Abstract: The spiral structure of the inner parts of the Galaxy is studied using 21 cm line data and stellar data. To study the neutral hydrogen distribution in the galactic layer a parameter η=τ(dV/dr) proportional to the mean densities is calculated using a first approximation for the velocity gradients due to differential rotation. The obtained distribution η(R, Z) shows spiral features completely consistent with the early star distribution and with the Hii regions. The corrugation effect of the galactic layer is observed in all the studied zones in neutral hydrogen and in the distribution of the OB stars in the Carina zone. The pattern obtained indicates four spiral arms for the inner parts of the Galaxy, three of which are identified also in the stellar data (arms -I, -II, and -III) and the more distant -IV in Hii regions. The local arm according to the stellar data of Kilkennyet al. forms a feature completely similar to the arms -I and -II and there are no indications that this arm is a special material branch between two main spiral arms as has been supposed in order to conciliate the neutral hydrogen pattern with the stellar distribution. The pitch angles for the spiral arms are approximately 13°–17°. The observed wave form distribution of the hydrogen cloud layer is completely consistent with the theoretical predictions of Nelson (1976) but there are no indications of such an effect in the intercloud hydrogen. The corrugated cloud layer has a width of 100 pc, a wave amplitude of 70 pc, and a wavelength which grows with the galactic center distance (approx. 2 kpc in the zones next to the galactic nucleus and 2.6–3.0 kpc in the zones next to the Sun). To each wavelength correspond two spiral arms. The spiral features in our Galaxy show characteristics quite similar to the features in the Andromeda nebula, not only in the component materials (neutral hydrogen, Hii regions and possibly also dust and stars) but also in their kinematics.

Journal ArticleDOI
TL;DR: In this paper, the spherically-symmetric steady-state cosmic-ray equation of transport in interplanetary space was developed for the Spherically Symmetric Stochastic Equation of Transport (SSTEOT).
Abstract: Green's Theorem is developed for the spherically-symmetric steady-state cosmic-ray equation of transport in interplanetary space. By means of it the momentum distribution functionFo(r,p), (r=heliocentric distance,p=momentum) can be determined in a regionra≤r≤rbwhen a source is specified throughout the region and the momentum spectrum is specified on the boundaries atraandrb. Evaluation requires a knowledge of the Green's function which corresponds to the solution for monoenergetic particles released at heliocentric radiusro, Examples of Green's functions are given for the casera=0,rb=∞ and derived for the cases of finiteraandrb. The diffusion coefficient κ is assumed of the form κ = κo(p)rb. The treatment systematizes the development of all analytic solutions for steady-state solar and galactic cosmic-ray propagation and previous solutions form a subset of the present solutions.

Journal ArticleDOI
TL;DR: The steepening of the proton spectrum beyond 1000 GeV and the rise in inelastic cross sections between 20 and 600 GeV observed by the PROTON-1-2-3 satellite experiments were explained by systematic effects of energy dependent albedo (backscatter) from the calorimeter as mentioned in this paper.
Abstract: The steepening of the proton spectrum beyond 1000 GeV and the rise in inelastic cross sections between 20 and 600 GeV observed by the PROTON-1-2-3 satellite experiments were explained by systematic effects of energy dependent albedo (backscatter) from the calorimeter.