Comparison of the characteristics of groups of stars in various evolutionary phases and the study of individual systems allow to make estimates of the parameters governing mass loss and mass transfer. Observations enable us in a few cases to determine geometric models for binaries during or after the mass transfer phase (disks, rings, common envelopes, symbiotics, interacting binaries, compact components).

From spectra taken at different phases, radial velocity curves can be derived and masses and radii can be determined. In special cases spectra in different spectral ranges (visual, UV, X-ray) are required for the determination of the radial velocities of the two components (for X-ray binaries, for systems with hot and cool components). Information on parameters related to the mass transfer process enables us to consider non conservative evolution - i.e. the computation of evolutionary sequences with the assumption that mass and angular momentum not only are transferred from one of the components towards the other one, but that also mass and angular momentum can leave the system. Careful and detailed analysis of the observations allows in certain cases to determine the parameters governing this mass and angular momentum loss, and for contact phases, to determine the degree of contact.

UVB Flight curves and spectrograms of R CMa obtained with the 48-inch telescope of Japal-Rangapur Observatory during 1980-82 have been used for deriving the eclipse and orbital elements as well as the absolute dimensions of the components. The primary is found to be a Main-Sequence F2V star of mass 1.52 M⊙ and the secondary a subgiant star of spectral type G8 and mass 0.20 M⊙ which fills its Roche lobe, in agreement with Kopal and Shapley (1956) results, Kopal (1959), or Sahade's (1963) results. From a consideration of the possible evolution of this system it is concluded that a large fraction of the original mass of the secondary is lost from the system. A study of the period changes indicates the possible presence of a third component of mass of about 0.5 M⊙ which is most likely to be an M dwarf.

This is a review of close binary systems with very early spectral types (B, O, Of, and WR stars). We limit our selection to systems with Roche model photometric solution only. There are 10 contact systems known at present. Three of them (V701 Sco, BH Cen, and RZ Pyx) are located in the vicinity of the zero-age contact (ZC) according to a Spectral Type - Period diagram. Only the first two systems have absolute dimensions available. Both of these fall into the ZC zone in the logP - logm diagram and the logm - logR diagram. The system TU Mus was thought to be a ZC system is located in the evolved contact zone (EC) in the above diagrams. Both V701 Sco and BH Cen were thought to be having mass ratios about unity. With the much improved light curves of BH Cen and new analysis the mass ratio has been revised to 0.84! This result may favor Shu's model for early-type zero-age contact systems. The evolved systems might be undergone Case A mass exchange except for two systems (V729 Cyg and RY Set) which might be from Case B. The systems V367 Cyg was classified by Plavec as a W Ser system may be a evolved contact system.

It is interesting to note that V729 Cyg (07f + Ofla), UW CMa(07f + O) and CQ Cep(WN7 + O) are all highly evolved contact systems. The Max II of UW CMa and CQ Cep are displaced to 0.78 and 0.80 phase, respectively. The displacement for V729 Cyg is not known due to poor coverage at this phase. The most distinct feature going from Of to Wolf-Rayet stars is the increasing domination of emission lines. It is suspected that this phaseshifts reflect the increasing activity of mass-flow in the common envelope.

There are 8 semidetached systems with reliable absolute dimensions. It is believed that 6 of them are derived from Case A while the remaining 2 are from Case B mass exchange.

The analysis of the UBV photoelectric study of the short period RS CVn eclipsing binary, UV Psc, has suggested that the primary is a transit with ɵe = 27°, i = 88.°5, and k = 0.75. The spectral type and luminosity of the hotter component is estimated to be G4-6V and that of the cooler component to be K.0-2V. Absolute dimensions for the components of UV Psc were derived by combining the present analysis with that of the spectroscopic analysis given by Popper.

The out-of-eclipse observations have showed large amount of scatter and an investigation of this showed that hotter component could be an intrinsic variable. No periodicity for this variation has been fixed due to lack of sufficient data.

Epsilon Aurigae has been observed during ingress and totality between 1982 and 1983 at Okayama. Analyses of profiles of Ha line and of radial velocities of neutral hydrogen and metals show that the secondary component consists of at least three parts in structure.

Binary systems displaying spectroscopic segregation, whereby line spectra of the two components overlap little or not at all in wavelength, account for a small subset of LUV objects (late-type ultraviolet). Optical and ultraviolet (IUE) spectra for one such system, HD 15351 + UV0225 + 13 (F4-5 V + sdO), are presented and a few related systems described. The role of LUV objects in establishing an absolute luminosity calibration for hot subdwarfs is emphasized, along with their significance for stellar evolution. A search strategy for additional spectroscopically segregated LUV objects is outlined.

We report recent International Ultraviolet Explorer (IUE) observations of two interacting binaries, R Arae and HD 207739. The ultraviolet spectra indicate the presence of optically-thick, variable hot plasma in those binary systems. These two binaries may belong to a class of binaries that are currently undergoing a rarely observed and probably short-lived phase in their evolution. Their properties are compared with those of two other interacting binaries, U Cephei and ß Lyrae.

The chromospheric-coronal emission of lower Main-Sequence single and binary stars can be correlated with an activity parameter of type R = g(B-V)P-1 where P is the rotation or orbital period and g(B-V) a function of the color resembling the convective turnover time. Observations indicate that the active region area coverage filling factor grows as R2, and the whole stellar surface becomes filled with closed loop structures at R ≂ 3. A braking formula is proposed (Equation 4) to include all periods (0.d1 ≲ R ≳ 30d) and spectral types F-M. On the basis of this equation, the mass transfer rates in compact binaries (driven by the gradual loss of orbital angular momentum) are discussed. It is concluded that the magnetic braking has good chances of being that mechanism which drives the mass transfer in cataclysmic variables and galactic bulge X-ray sources.

The structure of optically thick mass-losing envelopes of white dwarfs are studied in relation to nova outbursts. A sequence of steady mass-loss solutions is constructed for a nova outburst from the maximum photospheric radius to the disappearance. Much of mass of the envelope will be blown out.

Data on a large sample (∼400) of candidates for the classical Algol-type eclipsing binary configurations have been collected. The mass-ratio q has been calculated on the assumption of their semi-detached nature, and then compared with corresponding period for some subsets of the sample. The tendency to slight overluminosity (compared with corresponding MS stars) of the primaries in classical Algols is confirmed.

The role of the loss of angular momentum in classical Algol evolution is considered, together with a method for determining representative parameters to characterize such effects using the sample data. The possible existence of a class of post-contact classical Algols is noted.

An attempt is made to trace back the possible progenitor systems of the Algol-type binaries TU Mon, SX Cas, and DM Per. The present characteristics are compared to the result of the evolution of 9 M0 + 5.4 M0. The position of the hot components in the HRD is discussed with regard to the theoretical models.

The nutation effects of an accreting disk around SS 433 are analyzed within the framework of the fully relativistic model of Fang and Ruffini.

Some tens of harmonic components are found in the moving lines of SS 433, leaving a standard deviation of 0.002 in Z units, that is comparable to the observational error.

Ten harmonics appear anticorrelated in the two branches, among which those at 80,155, and 1500 days are also strong. Their behaviour indicates changing structure in the ejecting mechanism.

No secular change is occurring in the precessional 163-day period beyond the estimated error of 5 x 10-5 d-1. No periodicity occurs in beam velocity. One quarter of cases of (Z1 + Z2) are found outside their mean value by more than 5σ. This implies either variable beam velocity or absence of strict anti-parallelism.

Close binaries can evolve through various ways of interaction into compact objects (white dwarfs, neutron stars, black holes). Massive binary systems (mass of the primary M1 larger than 14 to 15 M0) are expected to leave, after the first stage of mass transfer a compact component orbiting a massive star. These systems evolve during subsequent stages into massive X-ray binaries. Systems with initial large periode evolve into Be X-ray binaries.

Low mass X-ray sources are probably descendants of lower mass stars, and various channels for their production are indicated. The evolution of massive close binaries is examined in detail and different X-ray stages are discussed. It is argued that a first X-ray stage is followed by a reverse extensive mass transfer, leading to systems like SS433, CirXl. During further evolution these systems would become Wolf-Rayet runaways. Due to spiral in these system would then further evolve into ultra short X-ray binaries like CygX-3.

Finally the explosion of the secondary will in most cases disrupt the system. In an exceptional case the system remains bound, leading to binary pulsars like PSR 1913 +16. In such systems the orbit will shrink due to gravitational radiation and finally the two neutron stars will coalesce. It is argued that the millisecond pulsar PSR 1937 + 214 could be formed in this way.

A complete scheme starting from two massive ZAMS stars, ending with a millisecond pulsar is presented.

Pre-Main-Sequence contracting objects, post-Main-Sequence expanding stars and mass-losing components of semi-detached systems all occupy more or less the same region in the conventional H-R-diagram. We make a transformation to variables Δ (logL) and Δ (log Te), where Δ is the difference between the observed quantity, log L or log Te, and the value of that quantity which a star of the same mass would have on the empirical Main Sequence. It is demonstrated that a plot between the new variables clearly separates the mass-losing stars from other objects which is essentially an effect of the increasing abundance of helium relative to hydrogen.

Space densities and galactic z-distributions of novae, recurrent novae, dwarf novae and symbiotic stars are newly determined and discussed in the context of earlier determinations. The data are then compared with the distributions of single and binary stars of possibly related types (late type giants, Mira variables, Algol systems, W UMa systems).

Novae and dwarf novae have similar distributions, those of fairly young stellar populations. The observed space density of potential novae (novalike objects) indicates that the mean recurrence time of novae might be as small as a few hundred years, which leads, with given nova shell masses and mass transfer rates in the minimum stage, to a secular decrease of the masses of the components undergoing nova outbursts.

Recurrent novae and symbiotic stars have distributions of older stellar populations, similar to those of late type giants and Mira variables.

On the basis of galactic distribution, novae and dwarf novae are closely related and may be final stages of W UMa systems, as well as progenitors of supernovae of type I. A small fraction of W UMa systems seems to belong to an older population. If evolutionary transitions between these types of stars can be substantiated, the presence of a minority of novae and dwarf novae in globular clusters and of supernovae I in elliptical galaxies can be explained.

Due to the lack of sufficiently well determined space distributions of Algol binaries, the suggestion that long-period Algol systems might be the progenitors of cataclysmic binaries can as yet neither be substantiated nor refuted. A very high space density of long-period Algol systems in the solar neighbourhood is derived. The observed space density of cataclysmic binaries could be explained by the transformation of a small percentage of the long-period Algol systems by common envelope evolution.

Since about ten years coordinated programs of photoelectric observations of asteroids are carried out to derive rotation rates and light curves. Quite a number of those asteroids exhibit features in their light curves, with similar characteristics as variable stars and especially eclipsing binaries. This would allow also an interpretation that there might be an evidence for the binary nature of some asteroids, based on observational hints. A few examples are given and a list of indications for the possible binary nature of asteroids, based on their light curve features, is presented.

The research activity in Japanese astronomy is described, taking into account the social and historical background. A trend in the last two decades is shown by the numbers of papers in 13 branches of astronomy. Major research facilities and international collaboration programs are summerized. Future programs under consideration are briefly discussed.

A giant radio telescope for observing galactic and extragalactic radio sources at metre wavelengths is proposed. By locating a parabolic cylindrical antenna at a site close to the Equator such that its axis lies parallel to earth's axis, it is possible to construct a large collecting area economically. The proposed instrument will be very powerful for studying compact and diffuse features of radio sources, monitoring their variability, recombination and deuterium line work, studies of interplanetary medium and pulsar search.

One of the prime astrophysical interests of the Observatorium Bosscha is, and has always been, double star research: visual double star research with the double-60 cm Zeiss telescope (dedicated in 1928), and theoretical research of evolved massive spectroscopic binaries (since 1972). For one thing, this is the very reason that this IAU Colloquium No. 80, celebrating the 60th anniversary of the Observatorium Bosscha in Lembang, is devoted to binary astrophysics.

Up to now, visual, photographic, and photometric tools have been used for binary research at the Observatorium Bosscha. An important, essential additional tool for binary research is spectrographic equipment, in order to measure radial velocities of binary components.