Abstract: It is shown that binary systems containing moderately young pulsars may emit high-energy neutrinos (between 1 and 100 TeV) at detectable levels. The pulsars are assumed to have total luminosities of the order of 10 to the 38th erg/sec. The neutrinos are produced by high energy particles (e.g. protons) from the pulsar striking the companion. Cyg X3 may be detectable in high-energy neutrinos if it emits greater than about 10 to the 35th erg/sec in high-energy protons. There may be a whole class of objects like Cyg X3, but obscured by thick accretion clouds.

Abstract: The linear polarization of the binary HD 47129 has been observed in the B filter on 60 nights The polarization has a variable component which is synchronous with the 144-day binary period This intrinsic component reaches a maximum at quadratures and may be explained by scattering from a corotating region of extrastellar material lying between the stars A best value of 71 deg is found for the orbital inclination

Abstract: The current state of knowledge of cosmic X-ray sources is reviewed, with a strong emphasis on observations in the photon energy range 0.5-10 keV. Two main types of galactic source are recognised-remnants of supernovae, and binary sources. In these the X-ray results from gravitational accretion onto a compact star-a neutron star or black hole, or possibly a white dwarf-of material from a normal, companion star. There also appear to be two main types of extragalactic X-ray source, which each have a total luminosity considerably in excess of the sum of those of the individual sources within the Galaxy, and so are a different class of object. These are galactic clusters and active galaxies.

Abstract: We discuss the rotation of interstellar clouds which are in a stage immediately before star formation. Cloud collisions seem to be the principal cause of the observed rotation of interstellar clouds. The rotational motion of the clouds is strongly influenced by turbulence.

Abstract: The masses of the components, the mass ratio, the semiaxis of the orbit, and the orbit angular momentum have been calculated for 826 spectroscopic binary stars. The distributions of the stars with respect to these parameters and their correlations are analyzed. The dependence of the statistical properties of spectroscopic binaries on their origin and evolution is discussed.

Abstract: Starting from the exact general relativistic expression for the total energy of selfgravitating spherically distributed matter and using the minimum energy priciple, we calculate the upper mass limit for a neutron star to be 3.1 solar masses.

Abstract: STROM AND HARRIS1 have detected a faint radio source (4 mJy at 6 cm) whose position is coincident, to within an error region of 3×18 arc s, with the 6mag late B star HD26676 (=HR1307). Although a prominent reflection nebula surrounds this star2, they argue convincingly1 that the nonthermal nature of the radio spectrum suggests identification with the star itself. As Strom and Harris stress, this association would be remarkable, as all previously identified radio stars are radio and optical variables and/or binaries. We report here that no such evidence exists for HD26676 or the radio source.

Abstract: It is shown that observations of both the hard X-ray and ..gamma..-ray light curves of Cyg X-3 find a natural explanation in a model for the system of a fast binary pulsar (with a period between 10 and 30 ms) surrounded by a cocoon (of scattering optical depth unity) located approx.10/sup 12/ cm from the pulsar. The possibility of direct observation of pulsations is discussed, and attention is called to an anomalous behavior of ..gamma..-rays in the vicinity of 0.5 MeV predicted by the model.

Abstract: The optical counterpart of 4U 1735-44, X-ray burst source MXB 1735-44, was studied with the 1.5-m telescope at Cerro Tololo, and by SAS 3, during the period between June 1 and 3, 1978. Explanations for the optical activity are discussed in terms of accretion instabilities onto a neutron star, or thermonuclear flashes on the neutron star itself. Attention is given to the timing of the bursts, which indicate that the burst source probably is located in a region within 1-2 light seconds from the X-ray source. In the binary case, it is noted that the optical emission is probably removed from the X-ray heated stellar atmosphere of the possible companion.

Abstract: With the equations of neutrino heat conductivity being used, the neutrino light curve is calculated for the spherically symmetrical collapse of an iron-oxygen 2M ⊙ star (Figure 1) up to the formation of a hot hydrostatically equilibrium neutron star. The total energy, radiated in the form of muon and electron neutrinos, is 5.8×1053 erg (0.16Mc 2). The mean neutrino particle energy is ∼12 MeV for all the time the collapse proceeds. The maximum neutrino luminosity value is equal to 3×1053 erg s−1. For a 10M ⊙ star collapse, the luminosity maximum 3×1054 erg s−1 takes place just at the moment of the formation of a black hole inside the collapsing star. The total radiated energy in this case is about 0.08Mc 2. The set of calculations, allowing for the deposition of momentum by means of neutrino-nuclear coherent scattering, brings us to a conclusion that the envelope outburst is only possible if the scattering cross-section is 50 times larger than the value experimentally accepted (inequality 20)).

Abstract: A bright IR source has been detected within a bright-rimmed dust cloud at the edge of the IC 1848 H II region. The source appears to be an early-type star with a circumstellar dust shell typical of protostars. This star is associated with the position of greatest CO excitation in a dense molecular cloud. The contours of CO emission correspond to those of the bright-rimmed dust cloud, showing that the star formed within the bright rim. Formaldehyde observations at 6 cm, 2 cm, and 2 mm are used to determine the density of the layer between the star and the ionized gas of the bright H..cap alpha.. rim. The location of this star, with respect to the dense molecular cloud which is subject to the external pressure of HII region, indicates the possible role of the expansion of IC 1848 in triggering star formation in dense regions at the perimeter of the H II region. The observed CO emission is used to determine the required luminosity of the embedded star. An early-type star of this luminosity should be detectable as a compact continuum source.

Abstract: We analyse the period distribution of eclipsing and spectroscopic binary systems, using various methods to take into account selection effects on observational data, with the purpose of deriving the actual distribution curve. The discussion of results shows the presence of some secondary maxima in the distribution which are probably of a non-statistical character. They could be regarded as an indirect clue to the discrete nature of the star formation process, according to the spiral density wave theory of galactic evolution by Linet al. (1969).

Abstract: THE ability of degenerate dwarfs, as opposed to neutron stars, to radiate at X-ray wavelengths has created much theoretical interest. Ariel 5 hard X-ray observations indicate that current theories seem inadequate to explain all aspects of the observations. Using the Imperial College hard X-ray scintillation telescope (ST) on Ariel 5, several short period (up to 12 h) binary star systems have been studied and are described here. This study was carried out after a very hard X-ray flux was detected from AM Herculis leading to a search for similar signals from optically similar star systems. The detector used consists of 8 cm2 of Csl crystal actively collimated to 8° FWHM and covers the energy range 26–1,200 keV. It is offset from the satellite spin axis, thereby enabling background subtraction using a modulation technique. The instrument and its operation are described fully elsewhere1.

Abstract: HARRISON1 has pointed out that the six radio pulsars with the smallest observed spin-down rates (Ṗ) are grouped together in a relatively small region of the sky, roughly in the direction of the galactic centre. To explain this particular effect he suggested that the intrinsic values of Ṗ are actually larger than the observed ones, because the barycentre of the Solar System would be accelerated (v≃10−6 cm s−2) in that direction. Harrison then suggested that this acceleration would be due to an hitherto undetected companion star of the Sun. He proposed a faint white, red (or even black) dwarf in a closed orbit, rather than a gas-accreting neutron star or black hole in an open orbit. We show here that a companion producing such an acceleration should almost certainly have been discovered because of its brightness in the infrared or visible region of the spectrum, depending on the character of the object. We conclude that Harrison's explanation is probably incorrect, and therefore we presume that the observed spin-down rates of these six pulsars (including the binary pulsar) are intrinsic and that their extreme values are due to the particular way in which the pulsars were formed. We show that the apparent clustering of these radio pulsars is a consequence of a strong observational selection effect and conclude that the distribution of all radio pulsars seems to be symmetric around the galactic centre.