Redetermination of the helium abundances in HII regions in Blue Compact Dwarf Galaxies     

V. V. Holovatyi  B. Ya. Melekh 《Astronomy Reports》2005,49(9):671-677

The He/H abundances in HII regions in Blue Compact Dwarf Galaxies are redetermined using the new recombination coefficients of Benjamin et al. The electron number density n _e in the He⁺ region, optical depth τ₃₈₈₉ in the HeI λ3889 Å line, and coefficient of underlying stellar absorption a_HeI are determined using the self-consistent method of Olive and Skillman. The primordial helium abundance and its enrichment are found using the helium abundances obtained in this paper and heavy-element abundances from our recent paper I: Y _p = 0.244 ± 0.004 and dY/dZ = 8.8 ± 4.6.  相似文献   

Determination of the chemical composition in HII regions of Blue Compact Dwarf Galaxies using an optimized photoionization modeling method     

V. V. Holovatyi  B. Ya. Melekh 《Astronomy Reports》2005,49(8):595-603

Optimized photoionization models of selected HII regions in Blue Compact Dwarf Galaxies are calculated with the aim of determining their chemical composition. The stability of the optimized-photoionization calculations and means of deriving the most accurate chemical abundances are checked. Initialization of the free physical parameters using different data sets, deviations from spherical geometry, and the introduction of gas-density fluctuations in an HII region do not affect the accuracy of the derived chemical compositions. The chemical abundances found for 12 HII regions using the optimized-photoionization models are used to derive the primordial helium abundance Y _p and its enrichment dY/dZ. The obtained values of Y _p and dY/dZ are close to values found previously using ionization-correction factors.  相似文献   

Evolutionary status of the spectral variable BD + 48°1220 = IRAS 05040+4820     

V. G. Klochkova  E. L. Chentsov  N. S. Tavolzhanskaya  V. E. Panchuk 《Astronomy Reports》2007,51(8):642-674

Based on high-resolution observations (R = 60 000 and 75 000), we have studied the optical spectral variability of the star BD + 48°1220, identified with the IR source IRAS 05040+4820. We have measured the equivalent widths of numerous absorption lines of neutral atoms and ions at wavelengths from 4500 Å to 6760 Å, as well as the corresponding radial velocities. We use model atmospheres to determine the effective temperature T _eff = 7900 K, surface gravity log g = 0.0, microturbulence velocity ξ _t = 6.0, and the abundances for 16 elements. The star’s metallicity differs little from the solar value: [Fe/H] = ?0.10 dex. The main peculiarity of the chemical composition of the star is a large helium excess, derived from the Hel λ 5876 Å absorption, [He/H] = +1.04, and the equally large oxygen excess, [O/Fe] = +0.72 dex. The carbon excess is small, [C/Fe] = +0.09 dex, and the ratio [C/O] < 1. We obtained an altered relation for the light-metal abundances: [Na/Fe] = +0.87 dex with [Mg/Fe] = ?0.31 dex. The barium abundance is low, [Ba/Fe] = ?0.84 dex. It is concluded that the selective separation of elements onto dust grains of the envelope is probably efficient. The radial velocity of the star measured from photospheric absorption lines over three years of observations varies in the interval V _⊙ = ?(7–15) km/s. Time-variable differential line shifts have been revealed. The entire set of available data (the luminosity M _v ≈ ?5 ^m , velocity V _lsr ≈ ?20 km/s, metallicity [Fe/H] = ?0.10, and peculiarities of the optical spectrum and chemical composition) confirms the status of BD + 48°1220 as a post-AGB star with He and O excesses belonging to the Galactic disk.  相似文献   

The gas emission spectrum in a star-forming region in the BCD galaxy VII Zw 403 (UGC 6456)     

V. P. Arkhipova  T. A. Lozinskaya  A. V. Moiseev  O. V. Egorov 《Astronomy Reports》2007,51(11):871-881

Observations with the 6-m telescope of the Special Astrophysical Observatory obtained with the MPFS panoramic spectrograph and a slit spectrograph with the SCORPIO focal reducer are used to analyze the emission spectrum of the ionized gas in a star-forming region in the BCD galaxy VII Zw 403. We present images of the galaxy’s central region in Hα, Hβ, [SII], and [OIII], together with maps of the relative [OIII]/Hβ and [SII]/Hα intensities. We have determined the parameters of the gas in bright ionized supershells, and estimated the relative abundances of oxygen, nitrogen, and sulfur; a low relative N/O abundance was detected.  相似文献   

Abundances of carbon,nitrogen, oxygen,and other elements in the atmospheres of the giants 15 ori and 22 <Emphasis Type="Italic">ɛ</Emphasis> sex     

T. M. Rachkovskaya 《Astronomy Reports》2008,52(1):53-60

We have used high-resolution spectra to study the giants 15 Ori and 22 ? Sex. The effective temperature T _eff = 7060 K, gravity log g = 3.16, and microturbulence velocity ξ _t = 3.5 km/s were determined for 15 Ori, with T _eff = 7350 K and log g = 3.90 for 22 ? Sex (the microturbulence velocity for 22 ? Sex was assumed to be ξ _t = 2.7 km/s). We estimated the abundances of C, N, O, Na, Si, Ca, Fe, and Ba (N and Ba, for 15 Ori only). The abundances of carbon, iron, and oxygen in 22 ? Sex are higher than the solar values by +0.31 dex, +0.33 dex, and +0.18 dex, respectively, while the calcium abundance is ?0.19 dex below the solar level. For 15 Ori, we find a slight carbon excess (+0.19 dex), a slight nitrogen deficiency (?0.13 dex), and a considerable deficiency of silicon (?0.42 dex). The abundances of the remaining elements in both stars are near-solar. We find no substantial differences between the abundances derived for 15 Ori and 22 ? Sex and the results of earlier studies of giants by both ourselves and Erspamer and North. A comparison of the atmospheric elemental abundances of giants and δ Scuti stars indicates that the abundances of some lighter elements (oxygen, sodium, silicon, and possibly nitrogen) are somewhat lower for δ Scuti stars than for A-F giants. We determined the masses, radii, luminosities, and ages for 15 Ori and 22 ? Sex.  相似文献   

Peculiarities of α-element abundances in Galactic open clusters     

V. A. Marsakov  M. L. Gozha  V. V. Koval’  L. V. Shpigel’ 《Astronomy Reports》2016,60(1):43-60

A catalog compiling the parameters of 346 open clusters, including their metallicities, positions, ages, and velocities has been composed. The elements of the Galactic orbits for 272 of the clusters have been calculated. Spectroscopic determinations of the relative abundances, [el/Fe], for 14 elements synthesized in various nuclear processes averaged over data from 109 publications are presented for 90 clusters. The compiled data indicate that the relative abundances of primary α elements (oxygen and magnesium) exhibit different dependences on metallicity, age, Galactocentric distance, and the elements of the Galactic orbits in clusters with high, elongated orbits satisfying the criterion (Z_max² + 4e²)^1/2 > 0.40 and in field stars of the Galactic thin disk (Z_max is the maximum distance of the orbit from the Galactic plane in kiloparsec and e is the eccentricity of the Galactic orbit). Since no systematic effects distorting the relative abundances of the studied elements in these clusters have been found, these difference suggest real differences between clusters with high, elongated orbits and field stars. In particular, this supports the earlier conclusion, based on an analysis of the elements of the Galactic orbits, that some clusters formed as a result of interactions between high-velocity,metal-poor clouds and the interstellar mediumof theGalactic thin disk. On average, clusters with high, elongated orbits and metallicities [Fe/H] < -0.1 display lower relative abundances of the primary a elements than do field stars. The low [O, Mg/Fe] ratios of these clusters can be understood if the high-velocity clouds that gave rise to them were formed of interstellar material from regions where the star-formation rate and/or the masses of Type II supernovae were lower than near the Galactic plane. It is also shown that, on average, the relative abundances of the primary a elements are higher in relatively metal-rich clusters with high, elongated orbits than in field stars. This can be understood if clusters with [Fe/H] > -0.1 formed as a result of interactions between metal-rich clouds with intermediate velocities and the interstellar medium of the Galactic disk; such clouds could form from returning gas in a so-called “Galactic fountain.”  相似文献   

Peculiarities of the abundances of neutron-capture elements in Galactic open clusters     

V. A. Marsakov  M. L. Gozha  V. V. Koval’  L. V. Shpigel’ 《Astronomy Reports》2016,60(1):61-72

The properties of the relative abundances of rapid and slow neutron-capture elements are studied using a catalog containing spectroscopic abundance determinations for 14 elements produced in various nuclear-synthesis processes for 90 open clusters. The catalog also contains the positions, ages, velocities, and elements of the Galactic orbits of the clusters. The relative abundances of both r-elements (Eu) and s-elements (Y, Ba, La, and Ce) in clusters with high, elongated orbits and in field stars of the Galactic thin disk display different dependences on metallicity, age, Galactocentric distance, and the elements of the Galactic orbits, supporting the view that these objects have different natures. In young clusters, not only barium, but also the three other studied s-elements display significantly higher relative abundances than field stars of the same metallicity. The relative abundances of Eu are lower in highmetallicity clusters ([Fe/H] > -0.1) with high, elongated orbits than in field giants, on average, while the [Eu/Fe] ratios in lower-metallicity clusters are the same as those in field stars, on average, although with a large scatter. The metallicity dependence of the [O, Mg/Eu] ratios in clusters with high, elongated orbits and in field stars are substantially different. These and other described properties of the Eu abundances, together with the properties of the abundances of primary a-elements, can be understood in a natural way if clusters with high, elongated orbits with different metallicities formed as a result of interactions of two types of high-velocity clouds with the interstellar medium of the Galactic disk: low-metallicity highvelocity clouds that formed from “primordial” gas, and high-metallicity clouds with intermediate velocities that formed in “Galactic fountains.”  相似文献   

Abundances of carbon,nitrogen, oxygen,and other elements in the atmospheres of the giants 25 Mon and HR 7389     

T. M. Rachkovskaya 《Astronomy Reports》2005,49(9):714-723

An analysis of high-resolution CCD spectra of the giant 25 Mon, which shows signs of metallicity, and the normal giant HR 7389 is presented. The derived effective temperatures, gravitational accelerations, and microturbulence velocities are T_eff = 6700 K, log g = 3.24, and ξ _t = 3.1 km/s for 25 Mon and T_eff = 6630 K, log g = 3.71, and ξ _t = 2.6 km/s for HR 7389. The abundances (log ε) of nine elements are determined: carbon, nitrogen, oxygen, sodium, silicon, calcium, iron, nickel, and barium. The derived excess carbon abundances are 0.23 dex for 25 Mon and 0.16 dex for HR 7389. 25 Mon displays a modest (0.08 dex) oxygen excess, with the oxygen excess for HR 7389 being somewhat higher (0.15 dex). The nitrogen abundance is probably no lower than the solar value for both stars. The abundances of iron, sodium, calcium (for HR 7389), barium, and nickel exceed the solar values by 0.22–0.40 dex for both stars. The highest excess (0.62 dex) is exhibited by the calcium abundance for 25 Mon. Silicon displays a nearly solar abundance in both stars—small deficits of ?0.03 dex and ?0.07 dex for 25 Mon and HR 7389, respectively. No fundamental differences in the elemental abundances were found in the atmospheres of 25 Mon and HR 7389. Based on their T_eff and log g values, as well as theoretical calculations, A. Claret estimated the masses, radii, luminosities, and ages of 25 Mon (M/M_⊙ = 2.45, log(R/R_⊙) = 0.79, log(L/L_⊙) = 1.85, t = 5.3 × 10⁸ yr) and HR 7389 (M/M_⊙ = 2.36, log(R/R_⊙) = 0.50, log(L/L_⊙) = 1.24, t = 4.6 × 10⁸ yr), and also of the stars 20 Peg (M/M_⊙ = 2.36, log(R/R_⊙) = 0.73, log(L/L_⊙) = 1.79, t = 4.9 × 10⁸ yr) and 30 LMi (M/M_⊙ = 2.47, log(R/R_⊙) = 0.73, log(L/L_⊙) = 1.88, t = 4.8 × 10⁸ yr) studied by the author earlier.  相似文献   

Helium and argon isotopes in lower crustal xenoliths from the belomorian mobile belt     

V. R. Vetrin  I. L. Kamenskii  S. V. Ikorskii 《Petrology》2007,15(3):302-313

The isotopic systematics of noble gases (He and Ar) were studied in Neoarchean and Paleoproterozoic lower crustal xenoliths from the Belomorian mobile belt. The xenolith suite is dominated by garnet granulites (Grt + Cpx + Pl ± Opx ± Qtz ± Kfs ± Phl ± Hbl) and two-pyroxene or garnet pyroxenites (Cpx + Pl ± Grt ± Opx ± Hbl ± Qtz). The xenoliths and the host Devonian ultramafic lamprophyres forming diatremes and explosion dikes contain fluid with similar He and Ar isotopic compositions. It was found that the fluid was trapped by the rocks and xenolith minerals approximately simultaneously with the formation of the lamprophyres. This conclusion is based on the identical K-Ar ages of the majority of xenoliths and ultramafic lamprophyres. When the xenoliths were transported toward the surface by high-temperature ultrabasic melts, the noble gases occurring in them were partly (Ar) or completely (He) lost. The melts were contaminated by meteoric waters during their emplacement in the upper crust, which resulted in that the Ar isotopic composition of lamprophyres approached the composition of atmospheric Ar. The fluid phase that was liberated during melt crystallization severely affected the xenoliths, diminishing the difference between the isotope compositions of He and Ar in the xenoliths and ultramafic lamprophyres. The He isotope composition includes an admixture of mantle ³He, which is suggested by the high measured ³He concentrations, exceeding the calculated values, and high ³He/³⁶Ar ratios in the xenoliths and their host lamprophyres. The fraction of the mantle component in the fluid trapped by the xenoliths was estimated as ～20%.  相似文献   

First findings of dinocysts in the upper Oligocene Turtas formation in Southern Tyumen oblast (West Siberia)     

O. B. Kuzmina  B. N. Shurygin 《Doklady Earth Sciences》2016,467(2):341-345

A new occurrence of dinocysts Pseudokomewuia in continental Cenosoic (Oligocene–Miocene) rocks of the West Siberian plain is identified. A complex of palynomorphs with dominant microphytoplankton (dinocysts) was found for the first time in the lacustrine-marsh sediments of the south of Tyumen oblast. The variable composition of the complex with Pseudokomewuia aff. laevigata He and Pseudokomewuia aff. granulata He species is traced upward through the section. The layers that correspond to the maximum abundance of Pseudokomewuia (akme) are distinguished and correlated with sections studied previously, which are located in the Barabinsk lithofacial region. Sediments with dinocysts are compared with sediments of the same age from North America, Northern Europe, and Southern China.  相似文献   

The galactic constants and rotation curve from molecular-gas observations     

V. S. Avedisova 《Astronomy Reports》2005,49(6):435-445

We obtained the photometric distances and radial velocities for the molecular gas for 270 star-forming regions and estimated the distance to the Galactic center from ten tangent points to be R₀ = 8.01 ± 0.44 kpc. Estimates of R₀ derived over the last decade are summarized and discussed; the average value is R₀ = 7.80 ± 0.33 kpc. We analyze deviations from axial symmetry of the gas motion around the Galactic center in the solar neighborhood. Assuming a flat rotation curve, we obtain Θ₀ ～ 200 km/s for the circular velocity of the Sun from regions beyond the Perseus arm. We used these Galactic constants to construct the Galactic rotation curve. This rotation curve is flat along virtually its total extent from the central bar to the periphery. The velocity jump in the corotation region of the central bar in the first quadrant is 20 km/s. We present analytical formulas for the rotation curves of the Northern and Southern hemispheres of the Galaxy for R₀ = 8.0 kpc and Θ₀ = 200 km/s.  相似文献   

Atmospheric chemical composition of the halo star HD 221170 from a synthetic-spectrum analysis     

V. F. Gopka  A. V. Yushchenko  T. V. Mishenina  Chulhee Kim  F. A. Musaev  A. V. Bondar’ 《Astronomy Reports》2004,48(7):577-587

The atmospheric abundances of 30 chemical elements in the halo star HD 221170 are analyzed by fitting synthetic spectra to observed spectra (i) with a resolution of 60 000 and signal-to-noise ratios of about 200 taken with the 1.93-m telescope of the Observatoire de Haute Provence and (ii) with a resolution of 35 000 and signal-to-noise ratios of more than 100 taken with the 2-m telescope of the Terskol Peak Observatory. The derived parameters of the stellar atmosphere are T_eff=4475 K, log g=1.0, [Fe/H]=?2.03, V_micro=1.7 km/s, and V_macro=4 km/s. The parameters T_eff, log g, [Fe/H], and V_micro can be determined by analyzing the variations of the rms error of the mean iron abundance derived using different model atmospheres. The chemical composition of the star’s atmosphere is analyzed. The abundances of a total of 35 elements in HD 221170 have been derived in this paper and in previous studies. Overall, the abundances of elements lighter than praseodymium are consistent with the elemental abundances in the atmospheres of stars with similar metal deficits. Copper and manganese are underabundant by ?2.9 and ?2.6 dex, respectively, relative to the Sun (when the analysis includes the effects of hyperfine structure). Heavy r-process elements (starting from praseodymium) are overabundant compared to iron-group elements. This can be explained by an enrichment in r-process elements of the material from which the star was formed.  相似文献   

The chemical composition of galactic planetary nebulae: Optimization photoionization modeling     

V. V. Holovatyy  B. Ya. Melekh  N. V. Havrylova 《Astronomy Reports》2008,52(4):327-334

Optimization photoionization models are computed for nine planetary nebulae with various metallicities with the aim of determining their chemical compositions. The algorithm used to compute the models is based on identifying best-fit values of the physical parameters of the nebulae by minimizing the χ² residual for fits to the observed spectra of these objects. The reliability of the results is investigated. The abundances of He, C, N, O, Ne, Si, S, and Ar are derived, as well as the physical characteristics of the nebulae. The Y -Z dependences (where Y and Z are the mass abundances of helium and heavy elements, respectively) are analyzed for the planetary nebulae together with HII regions in blue compact dwarf galaxies. The primordial helium abundance, Y _p = 0.2479 ± 0.0014, and dY/dZ = 2.99 ± 0.32 are determined, and found to be close to the corresponding values obtained using ionization correction factors.  相似文献   

Infrared Morphology of Regions of Ionized Hydrogen     

A. P. Topchieva  D. S. Wiebe  M. S. Kirsanova  V. V. Krushinskii 《Astronomy Reports》2017,61(12):1015-1030

A search for infrared ring nebulae associated with regions of ionized hydrogen has been carried out. The New GPS Very Large Array survey at 20 cm forms the basis of the search, together with observations obtained with the Spitzer Space Telescope at 8 and 24 μm and the Herschel Space Telescope at 70 μm. Objects having ring-like morphologies at 8 μm and displaying extended emission at 20 cm were selected visually. Emission at 24 μm having the form of an inner ring or central peak is also observed in the selected objects. A catalog of 99 ring nebulae whose shapes at 8 and 70 μm are well approximated by ellipses has been compiled. The catalog contains 32 objects whose shapes are close to circular (eccentricities of the fitted ellipses at 8 μm no greater than 0.6, angular radius exceeding 20″). These objects are promising for comparisons with the results of one-dimensional hydrodynamical simulations of expanding regions of ionized hydrogen.  相似文献   

Radial pulsations of helium stars and a model for BX CIR     

Yu. A. Fadeev  M. F. Novikova 《Astronomy Reports》2003,47(1):68-74

The results of hydrodynamical calculations of radially pulsating helium stars with masses 0.5M_⊙≤M≤0.9M_⊙, bolometric luminosities 600L_⊙≤5×10³L_⊙, and effective temperatures 1.5×10⁴ K≤T_eff≤3.5×10⁴ K are presented. The pulsation instability of these stars is due to the effects of ionization of iron-group elements in layers with temperatures T～2×10⁵ K. The calculations were carried out using opacities for the relative mass abundances of hydrogen and heavy elements X=0 and Z=0.01, 0.015, and 0.02. Approximate formulas for the pulsation constant Q over the entire range of pulsation instability of the hot helium stars in terms of the mass M, radius R, effective temperature T_eff, and heavy-element abundance Z are derived. The instability of BX Cir to radial pulsations with the observed period Π=0.1066 d occurs only for a mass M≥0.55M_⊙, effective temperature T_eff≥23000 K, and heavy-element abundance Z≥0.015. The allowed mass of BX Cir is in the range 0.55M_⊙≤M≤0.8M_⊙, which corresponds to luminosities 800L_⊙≤M≤1400L_⊙ and mean radii 1.7R_⊙?R?2.1R_⊙.  相似文献   

Measurements of the scattering of pulsar radio emission     

A. D. Kuz’min  B. Ya. Losovskii  K. A. Lapaev 《Astronomy Reports》2007,51(8):615-623

Measurements of the broadening of pulsar pulses by scattering in the interstellar medium are presented for a complete sample of 100 pulsars with Galactic longitudes from 6° to 311° and distances to three kiloparsec. The dependences of the scattering on the dispersion measure (τ _sc(DM) ∝ DM^α), frequency (τ _sc(v) ∝ v ^?γ ), Galactic longitude, and distance to the pulsar are analyzed. The dependence of the scattering on the dispersion measure in the near-solar neighbourhood can be represented by the power law τ _sc(DM) ∝ DM^2.2±0.1). Measurements at the low frequencies 111, 60, and 40 MHz and literature data are used to derive the frequency dependence of the scattering (τ _sc(v) ∝ V ^?γ ) over a wide frequency interval (covering a range of less than 10: 1) with no fewer than five frequencies. The index for the frequency dependence, γ = 4.1 ± 0.3, corresponds to a normal distribution for inhomogeneities in the turbulence in the scattering medium. Based on an analysis of the dependence of the scattering on the distance to the pulsar and on Galactic longitude, on average, the turbulence level C _n ² is the same in all directions and at all distances out to about three kpc, testifying to the statistical homogeneity of the turbulence of the scattering medium in the near-solar region of the Galaxy.  相似文献   

Analysis of magnetic activity of the rapidly rotating stars He 373 and AP 225     

A. I. Kolbin  V. V. Tsymbal 《Astronomy Reports》2017,61(6):521-532

Spectroscopic and photometric data for the two rapidly rotating members of the α Persei cluster He 373 and AP 225 are analyzed. Improved estimates have been obtained for the projected equatorial rotation velocities: v sin i = 164 km/s for He 323 and v sin i = 129 km/s for AP 225. Multi-band photometric mapping is used to map the spot distributions on the surfaces of the two stars. The fractional spotted areas S and mean temperature difference ΔT between the unspotted photosphere and the spots are estimated (S = 7% and ΔT = 1000 K for He 373; S = 9% and ΔT = 800 K for AP 225). The H _α line profiles of both stars have variable emission components whose widths are used to deduce the presence of extended regions of emission reaching the corotation radius.  相似文献   

The mass of the black hole in the X-ray binary LMC X-1     

M. K. Abubekerov  E. A. Antokhina  N. Yu. Gostev  A. M. Cherepashchuk  V. V. Shimansky 《Astronomy Reports》2016,60(12):1029-1034

A dynamical estimate of the mass of the black hole in the LMC X-1 binary system is obtained in the framework of a Roche model for the optical star, based on fitting of the He I 4471 Å and He II 4200 Å absorption lines assuming LTE. The mass of the black hole derived from the radial-velocity curve for the He II 4200 Å line is m_x = 10.55 M_⊙, close to the value found earlier based on a model with two point bodies [1].  相似文献   

Masses of the visual components and black holes in X-ray novae: Effects of proximity of the components     

V. S. Petrov  E. A. Antokhina  A. M. Cherepashchuk 《Astronomy Reports》2017,61(5):377-386

It is shown that the approximation of the complex, tidally distorted shape of a star as a circular disc with local line profiles and a linear limb-darkening law, which is usually applied when deriving equatorial stellar rotation velocities from line profiles, leads to overestimation of the equatorial velocity V _rot sin i and underestimation of the component mass ratio q = M _x /M _v . A formula enabling correction of the effect of these simplifying assumptions on the shape of a star is used to re-determine the mass ratios q and the masses of the black holes M _x and visual components M _v in low-mass X-ray binary systems containing black holes. Taking into account the tidal–rotational distortion of the stellar shape can significantly increase the mass ratios q = M _x /M _v , reducing M _v , while M _x changes only slightly. The resulting distribution of M _v attains its maximum near M _v ? 0.35M _⊙, in disagreement with the results of population synthesis computations realizing standard models for Galactic X-ray novae with black holes. Possible ways to overcome this inconsistency are discussed. The derived distribution of M _x also differs strongly from the mass distribution for massive stars in the Galaxy.  相似文献   

Galactic parameters derived from open-cluster data     

T. P. Gerasimenko 《Astronomy Reports》2004,48(2):103-107

The components U₀ and V₀ of the solar motion and the Oort constant A₀ are determined using the data of a homogeneous open-cluster catalog with corrected distance moduli. The results are based on a sample of 146 open clusters with known radial velocities located in the Galactic plane (b<7°) within 4 kpc of the Sun. The solar Galactocentric distance R₀ is determined using two kinematic methods. The following results are obtained: A₀=17.0±0.9 km/s kpc, U₀=10.5±1.0 km/s, V₀=11.5±1.1 km/s, R₀=8.3±0.3 pc.  相似文献