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The Triple System HR 7272
Udry, S.; Griffin, R. F.; Tokovinin, A. A. +2 more
A combined spectroscopic-interferometric orbit is computed for the primary component of the visual binary star HR 7272 = ADS 12101. The orbital period is 3.55 years; semimajor axis 0.074 arcsec. Radial velocities of both components were determined by correlation techniques; their semi-amplitudes are 6.6 and 8.4 km/s. Because those amplitudes are s…
Analysis of the HST Ultraviolet Spectra for T Tauri Stars: RY Tau and HD115043
Lamzin, S. A.
The ultraviolet spectra of the stars RY Tau and HD115043 from the Hubble Space Telescope are analyzed. RY Tau belongs to the classical T Tauri stars, while HD115043 is a young (t ~ 3 x 10^8 years), chromospherically active star. The most intense emission lines were identified, and their fluxes were measured. Low-resolution spectra of RY Tau and HD…
Analysis of HST Ultraviolet Spectra for T Tauri Stars: RU Lup
Lamzin, S. A.
The ultraviolet spectra of the star RU Lup obtained with the Hubble Space Telescope are analyzed. Emission lines are identified. The presence of absorption components with a nearly zero residual intensity in the MgII resonance doublet lines is indicative of mass outflow with a velocity V_infty = 300 km/s. These lines also exhibit a broad (1400 km/…
Evolution of the Symbiotic Star AS338 after Its Strong Outburst in 1983
Munari, U.; Mikolajewska, J.; Kolotilov, E. A. +5 more
The photometric UBV observations of AS338 that we began after its outburst in 1983 are presented. They were accompanied by yearly spectroscopic observations and by occasional estimations of the star's infrared JHKL magnitudes. In June 1993, the star's optical spectrum was extended to the ultraviolet via IUE observations of AS338. Collectively, the…
The Orbit of the Nearby Low-Mass Binary Gliese 600
Weigelt, G.; Hofmann, K. -H.; Tokovinin, A. A. +1 more
We have computed a combined spectroscopic-interferometric orbit for the nearby binary Gliese 600 discovered by us. The orbital period is 2.78 years, and the semimajor axis is 100 mas (0.1"). Its M0V components are almost identical and have a mass of 0.5 M_solar. The mass ratio is uncertain because of the low radial-velocity semiamplitude (7 km/s) …
Internal Rotation of the Sun as Inferred from GONG Observations
Gavryusev, V. G.; Gavryuseva, E. A.; di Mauro, M. P.
Helioseismology is a direct and most informative method of studying the structure and dynamics of the Sun. Determining the internal differential rotation of the Sun requires that the frequencies of its eigentones be estimated with a high accuracy, which is possible only on the basis of continuous long-term observations. The longest quasi-continuou…
Tidal Structures of z ~ 1 Galaxies in the Hubble Deep Field
Reshetnikov, V. P.
An analysis of the images of objects in the Northern Hubble Space Telescope Deep Field has revealed twelve galaxies with tidal tails at redshifts from 0.5 to 1.5. The integrated characteristics of the newly discovered tidal structures are found to be similar to those of the tails of local interacting galaxies. The space density of galaxies with ti…
Effects of a Micrometeorite Stream on the Accuracy of Astrometric Measurements by Scanning Space-Borne Instruments
Mikisha, A. M.; Rykhlova, L. V.; Smirnov, M. A.
The effect of micrometeorite impacts upon the surface of a spacecraft on the accuracy of astrometric measurements made by scanning with instruments onboard the spacecraft is considered. This effect is shown to be marginal for HIPPARCOS measurements. However, disregarding this kind of effect for all the currently projected spacecraft may result in …