A study of the nature of the Hα-emission stars LkHα112, 115, 118, and 119

The present study of the nature of the stars LkH112, LkH115, LkH118, and LkH119 is based on low-dispersion IDS spectra and photometric measurements in the wavelength range between 0.33 and 3.8 m. These stars are located in the direction of the extremely young open cluster NGC 6530 (Walker, 1957). The purpose of this study is, in general, to know whether they belong to the group of intermediate mass pre-main sequence objects, also known as Herbig Ae/Be stars, and, in particular, what special characteristics they possess. The result is as follows. The stars are very young; probably only LkH112 and LkH115 are members of the above-mentioned class of objects. The membership of LkH118 and LkH119 in this group is doubtful.Based on observations made at the European Southern Observatory, La Silla, Chile.     

Chromospheric variability in late-type dwarfs from high-resolution spectra of Caii H

Precise photometric observations of stars in the double cluster h and Persei reveal a large spread in the colours and magnitudes of the upper Main-Sequence; half of the stars are variables that are Be stars or related stars. The reported age difference between both clusters is found to be spurious. Rotation apparently affects both the intrinsic and the observed colours of the early-type stars in h and Persei. This result questions the validity of photometric calibrations that heavily rely on h and Persei or similar clusters.Paper presented at the 11th European Regional Astronomical Meeting of the IAU on New Windows to the Universe, held 3–8 July, 1989, Tenerife, Canary Islands, Spain.     

ОБ ионизации межзвездного магния

, , , , ,S , , , S _Mg. , . , . , ( , ..). B5 B0; (<1%).     

IRSPEC observations of planetary nebulae

We have obtained infrared spectra of planetary nebulae in the 3.0–3.8 m range using IRSPEC, the ESO grating infrared spectrograph, attached to the 3.6-m telescope. We find evidence of an evolution of the carriers of the unidentified emission bands in the 3 m region, and explain the observed behaviour in terms of ion irradiation from fast stellar wind.Based on observations collected at the European Southern Observatory, La Silla, Chile.Paper presented at the 11th European Regional Astronomical Meetings of the IAU on New Windows to the Univers, held 3–8 July, 1989, Tenerife, Canary Islands, Spain.     

Движение малых частиц в окрестностях протосолнца переменной светимости

, , , , . , . , () (), , , . — .     

Hubble sequence,angular momenta and time-scales of the early evolution of galaxies

The empirical evidence for a connection between type and relative angular momentum of galaxies is reviewed and some constraints for the theoretical explanation are discussed.

---

.

     

Stellar mass loss in late B-type supergiants

A study using archive IUE data of time-varying mass loss has been carried out for a sample of 12 supergiants in the spectral range B5–B9. Additionally dedicated IUE velocity-time observations of discrete absorption components (DAC) in the UV resonance lines have been made for one of the stars (Ori), while optical data obtained for this star shows time variability in the H profile. Ions in which mass-loss features occur are unambiguously identified by comparing spectra of the stars at different mass loss episodes. Time variability in the mass-loss activity of late B-type supergiants is discussed and the stars are examined for trends with effective temperature. The basis for a theoretical model of the stellar wind in these stars is introduced.Paper presented at the 11th European Regional Astronomical Meetings of the IAU on New Windows to the Universe, held 3–8 July, 1989, Tenerife, Canary Islands, Spain.     

New insight on the rapid rotator HD 199178

Optical spectra were obtained of the rapidly rotating star HD 199178 to analyze the H profile. Excess emission was derived by subtracting a comparison star spectrum. The H line fluxes variability is stressed together with the discussion of this and previous data in the context of the surface phenomena for the FK Com family of stars.Paper presented at the 1th European Regional Astronomical Meetings of the IAU on New Windows to the Universe, held 3–8 July, 1989, Tenerife, Canary, Islands, Spain.     

Critical inclinations in planetary problems

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.

     

Narrow-band photometry of Wolf-Rayet stars and planetary nebulae

We present observational data in the (16)(9)(25)-photometric system for 11 Wolf-Rayet stars and 7 planetary nebulae. The results show anomalous (16)(9)-indices for these emission objects. Six W-R stars show possible variations in the strength of the HeII line at 6560 Å, perhaps none in the strength of the HeI line at 10830 Å. In spite of these misconstrued (16) and (9)-indices, most WC stars are separated from WN stars in the (16)(9)-array; and PN, in this diagram lie far apart from all kind of stellar objects. The results, yielded by the (25)-index, indicate that the HeI and HeII lines at 10830 Å and 10124 Å, respectively, are probably well suited for photometric examination in W-R stars, PN and other peculiar objects.Paper presented at the 11th European Regional Astronomical Meetings of the IAU on New Windows to the Universe, held 3–8 July, 1989, Tenerife, Canary Islands, Spain.     

Околозвездные оБлака по данным 2800 Mgii

2800 Mgii (. 1). (N ⁺/N ₁1000) , , (N ⁺/N ₁10). , . —, , . — . : ; 0.002 1 , 0.1 ; () 100 ^–3; ; ; , 10 ; 10^–4 1 . 2800 Mgii .     

Auvbyβ survey for Ca II emission stars

During the last two years auvby photometric survey of 85 Ca II emission stars from the Mount Wilson program on stellar activity has been carried out at the Calar Alto Observatory (Almeria, Spain). We present preliminary results for theuvby and calibrations. Some stars displaying anomalousc ₁ andm ₁ indices, with photometric or spectroscopic data from previous studies, are reported. A reddening study for the complete sample is given.Paper presented at the 11th European Regional Astronomical Meetings of the IAU on New Windows to the Universe, held 3–8 July, 1989, Tenerife, Canary Islands, Spain.     

Пе⌕вичный адрон: Происхождение звезд галактик и астрономицеской вселенной

, J=(m/m _p)^1+1/n , n=2 , n=3 , . , . , , . - wc m _P, G c . -.     

Некоторые нелинейные эффекты В релятивистской задаче двух тел

- , . . , . - .     

Оπорная селенодезическая система координат по гелиометрическим наБлюдениям луны В казани

, 1969–1975 .., 32 . , .     

Variability of Circumstellar Emission from Dust Envelopes Around Carbon Stars

The main constituents of the dust, produced around late-type carbon stars, are thought to be carbon and silicon carbide (SiC), although their exact nature is not yet well established. This subject has been addressed by several authors and good fits of a large number of IRAS sources (chosen among the carbon stars exhibiting the SiC feature at about 11.3 m) were obtained. In this work we use the same procedure on a limited number of objects, of the same type, taking into account the variability of such sources and the changes induced in their IR spectra. For this purpose, the chosen stars have been observed with a spectral resolution higher than that available for the IRAS data (/ 50), using the CGS3 instrument of the UKIRT telescope, both in the low ( / 160) and in the high ( / 500) resolution configuration. The results are discussed and some preliminary conclusions are drawn.     

Взаимодействие вещества и излучения В Горячей модели вселенной

. , , . , t>10¹⁰ ( z<10⁵) .

---

In this paper we continue the work of Weymann, investigating the causes of distortion of the spectrum of the residual radiation from the Planck curve. We discuss the distortion to the spectrum, resulting from recombination of primeval plasma.We then derive an analytic expression for the distortion to the equilibrium spectrum due to Compton scattering by hot electrons. On the basis of the observational data we conclude that a period of the existence of neutral hydrogen is inescapable in the hot model of the universe. It is concluded that any injection of energy att>10¹⁰ sec (red shiftz<10⁵) give the distortions of the equilibrium spectrum.

     

Reddening map around α Orionis

uvby photometry has been done for early-type stars in the surroundings of the shell star Ori. The reddening maps show the presence of irregularly distributed absorbing material.Paper presented at the 11th European Regional Astronomical Meetings of the IAU on New Windows to the Universe, held 3–8 July, 1989, Tenerife, Canary Islands, Spain.     

Le développement du potentiel dans le cas d'une densité analytique

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.

---

. , , , .

     

К теории кривых Блеска сверхновых звезд

, . . . (10R ) ( 10 000R ). NGC 5457, NGC 6946 NGC 5236. , , II I . . . , . . 10⁵⁰÷10⁵² , .