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1.
High-resolution optical spectroscopy of the V2324 Cyg variable star associated with the IR source IRAS 20572+4919 is performed for the first time. More than 200 absorption features (mostly Fe II, Ti II, Cr II, Y II, Ba II, and Y II) are identified in the wavelength interval from 4549 to 7880 Å. The spectral type and rotation velocity of the star are found to be F0 III and V sin i = 69 km/s, respectively. Neutral-hydrogen and NaI D lines have complex P Cyg-type profiles. Neither systematic trend of radial velocity Vr with line depth Ro nor temporal variability of Vr have been found. We found that the value for the average heliocentric radial velocity is Vr = ?16.8 ± 0.6 km/s. The radial velocities inferred from the cores of the absorption components of the Hβ and NaI wind lines vary from ?140 to ?225 km/s (and the expansion velocities of the corresponding layers, from about 120 to 210 km/s). The maximum expansion velocity is found for the blue component of the split Hα absorption: 450 km/s for December 12, 1995. The method of model atmospheres is used to determine the following parameters of the star: effective temperature T eff = 7500 K, surface gravity log g = 2.0, microturbulence velocity ξ t = 6.0 km/s, and metallicity, which is equal to the solar value. The main peculiarity of the chemical composition of the star is the overabundance of lithium and sodium. The results cast some doubt on the classification of V2324 Cyg as a post-AGB star.  相似文献   

2.
We present the results of the reduction of our photometric and spectroscopic observations for the eclipsing binary SZ Cam performed with the telescopes at the Astronomical Observatory of the Ural Federal University and the Special Astrophysical Observatory of the Russian Academy of Sciences in 1996–2014. Based on an 11-year-long photometric monitoring of SZ Cam, we have obtained new elements of its photometric orbit and parameters of its components. We have detected low-amplitude periodic light variations in SZ Cam that are possibly related to the ellipsoidal shape of the components of the spectroscopic binary third body. Based on published data and our new spectroscopy, we have found new values for the mass ratio, q = 0.72 ± 0.01, and parameters of the radial velocity curves of the components, V 0 = ?3.6 ± 1.7 km s?1, K 1 = 190.2 ± 1.9 km s?1, and K 2 = 263.0 ± 2.4 km s?1. The component masses have been estimated to be M 1 = 16.1 M ⊙ and M 2 = 11.6 M ⊙. We have obtained new light elements and parameters of the radial velocity curves for the third body, V 0 3b = 4.2 ± 0.6 km s?1 and K 1 3b = 26.6 ± 0.8 km s?1. We have improved the period of the relative orbit of SZ Cam and the third body, P orb = 55.6 ± 1.5 yr.  相似文献   

3.
Based on published data, we have collected information about Galactic maser sources with measured distances. In particular, 44 Galactic maser sources located in star-forming regions have trigonometric parallaxes, proper motions, and radial velocities. In addition, ten more radio sources with incomplete information are known, but their parallaxes have been measured with a high accuracy. For all 54 sources, we have calculated the corrections for the well-known Lutz-Kelker bias. Based on a sample of 44 sources, we have refined the parameters of the Galactic rotation curve. Thus, at R 0 = 8kpc, the peculiar velocity components for the Sun are (U ⊙, V ⊙, W ⊙) = (7.5, 17.6, 8.4) ± (1.2, 1.2, 1.2) km s?1 and the angular velocity components are ω 0 = ?28.7 ± 0.5 km s?1 kpc?1, ω 0′ = +4.17 ± 0.10 km s?1 kpc?2, and ω0″ = ?0.87 ± 0.06 km s?1 kpc?3. The corresponding Oort constants are A = 16.7 ± 0.6 km s?1 kpc?1 and B = ?12.0 ± 1.0 km s?1 kpc?1; the circular rotation velocity of the solar neighborhood around the Galactic center is V 0 = 230 ± 16 km s?1. We have found that the corrections for the Lutz-Kelker bias affect the determination of the angular velocity ω 0 most strongly; their effect on the remaining parameters is statistically insignificant. Within themodel of a two-armed spiral pattern, we have determined the pattern pitch angle $i = - 6_.^ \circ 5$ and the phase of the Sun in the spiral wave χ 0 = 150°.  相似文献   

4.
We report a catalog of 509 pairs identified among 10403 nearby galaxies with line-of-sight velocities V LG < 3500 km/s. We selected binary systems in accordance with two criteria (“bounding” and “temporal”), which require the physical pair of galaxies to have negative total energy and its components to be located inside the zero-velocity surface. We assume that individual galaxy masses are proportional to their total K-band luminosities, M = L K × 6M ⊙/L ⊙. The catalog gives the magnitudes and morphological types of galaxies and also the projected (orbital) masses and pair isolation indices. The component line-of-sight velocity differences and projected distances of the binary systems considered have power-law distributions with the median values of 35 km/s and 123 kpc, respectively. The median mass-to-K-band luminosity ratio is equal to 11M ⊙/L ⊙, and its uncertainty is mostly due to the errors of measured velocities. Our sample of binary systems has a typical density contrast of δρ/ρ c ～ 500 and a median crossing time of about 3.5 Gyr. We point out the substantial fraction of binary systems consisting of late-type dwarf galaxies, where the luminosities of both components are lower than that of the Small Magellanic Cloud. The median projected distance for 41 such pairs is only 30 kpc, and the median difference of their line-ofsight velocities is equal to 14 km/s which is smaller than the typical error for radial-velocity (30 km/s). This specific population of gas-rich dwarf binary galaxies such as I Zw 18 may be at the stage immediately before merging of its components. Such objects, which are usually lost in flux-limited (and not distance-limited) samples deserve a thorough study in the HI radio line with high spatial and velocity resolution.  相似文献   

5.
The paper presents the results of spectroscopic research of the high-mass X-ray binary IGRJ17544-2619 optical component that were carried out with the RTT-150. The analysis of a long series of spectroscopic observations of the optical star of IGRJ17544-2619 system in 2007–2011 was carried out. Orbital parameters of the system were obtained: γ-velocity of 47 km/s, semiamplitude of radial velocity curve K = 30.5 km/s, eccentricity e = 0.44, longitude of the periastron ω = 142°, and an orbital period of the system of 12.17 days. The lower limit of the compact object mass was found to be equal to M = 2.82M ⊙.  相似文献   

6.
We present the results of our spectroscopic observations of the eclipsing binary SZ Cam performed with the 1-m (Zeiss-1000) and 6-m (BTA) telescopes at the Special Astrophysical Observatory of the Russian Academy of Sciences in 2000 and 2003. Based on our results and published data, we have calculated new values for the component mass ratio, q = 0.72 ± 0.02, the radial velocity of SZ Cam relative to the Solar system barycenter, V 0 =?10.6 ± 2.0 km s?1, and the semi-amplitudes of the radial velocity curves for both components, K 1 = 192.0 ± 2.6 and K 2 = 266.4 ± 2.5 km s?1. The orbital semimajor axes and masses of the components have been determined: α1 = 10.4R ⊙, α2 = 14.5R ⊙, M 1 = 16.7M ⊙, M 2 = 12.0M ⊙. New light elements and parameters of the radial velocity curve for the third body have been obtained. The mass of the secondary component of the third body M 2 3b is discussed. Its lower limit is estimated to be M 2 3b = 1.4M ⊙.  相似文献   

7.
This paper is the first of a series considering the properties of distribution of nearby galaxies in the low density regions. Among 7596 galaxies with radial velocities V LG < 3500 km/s, absolute magnitudes M K < ?18?4, and Galactic latitudes |b| > 15° there are 3168 field galaxies (i.e. 42%) that do not belong to pairs, groups or clusters in the Local universe. Applying to this sample the percolation method with a radius of r 0 = 2.8Mpc, we found 226 diffuse agglomerates with n ?? 4 number of members. The structures of eight most populated objects among them (n ?? 25) are discussed. These non-virialized agglomerates are characterized by amedian dispersion of radial velocities of about 170 km/s, the linear size of around 6 Mpc, integral K-band luminosity of 3 × 1011 L ??, and a formal virial-mass-to-luminosity ratio of about 700M ??/L ??. The mean density contrast for the considered agglomerates is only $\left\langle {\Delta n/\bar n} \right\rangle $ ?? 5, and their crossing time is about 30?C40 Gyr.  相似文献   

8.
The results of analyzing variations in the line-of-sight (LOS) velocities in the solar loop at photospheric and chromospheric levels in the region of emerging magnetic flux for the evolving active region NOAA 11024 are reported. The analysis combines the data of multiwave spectropolarimetric observations that were carried out on July 4, 2009, (Tenerife, Spain) using THEMIS solar telescope and the data obtained with GOES, SOHO, and STEREO cosmic satellites. A complex sequence of active events has been studied: formation of the Ellerman bomb, B1 X-ray microflare, and four chromospheric surges that were formed as a result of magnetic reconnection caused by new emerging magnetic flux. The Ellerman bomb was formed in the vicinity of a growing pore. Variations in the velocity V LOS of the EB had an oscillation character for chromosphere and photosphere. Before the microflare, the average velocities of the upward and downward plasma fluxes in one leg of the magnetic loop were nearly the same—26 km/s. During the microflare, the velocity V LOS of the ascending and descending flows increased up to ?33 and 50 km/s, respectively. Variations in line-of-sight velocity of a plasma in the second leg of the magnetic loop correlated well with variations of V LOS in the region of microflare, but they occurred 1.5 minutes later. During the time of observations, four chromospheric ejections of matter were formed and three of them occurred in the region of Ellerman’s bomb formation. Sharp variations in the soft X-ray intensity occurred during these ejections. At photospheric level, variations in the line-of-sight velocity of plasma in the legs of the loop occurred in the opposite direction. In the region of the first leg, velocity V LOS diminished from ?1.8 to ?0.4 km/s, while the velocity increased from ?0.6 to ?2.6 km/s in the region of the second leg.  相似文献   

9.
To study the peculiarities of the Galactic spiral density wave, we have analyzed the space velocities of Galactic Cepheids with propermotions from the Hipparcos catalog and line-of-sight velocities from various sources. First, based on the entire sample of 185 stars and taking R 0 = 8 kpc, we have found the components of the peculiar solar velocity (u ⊙, v ⊙) = (7.6, 11.6) ± (0.8, 1.1) km s?1, the angular velocity of Galactic rotation Ω0 = 27.5 ± 0.5 km s?1 kpc?1 and its derivatives Ω′0 = ?4.12 ± 0.10 km s?1 kpc?2 and Ω″0 = 0.85 ± 0.07 km s?1 kpc?3, the amplitudes of the velocity perturbations in the spiral density wave f R = ?6.8 ± 0.7 and f θ = 3.3 ± 0.5 km s?1, the pitch angle of a two-armed spiral pattern (m = 2) i = ?4.6° ± 0.1° (which corresponds to a wavelength λ = 2.0 ± 0.1 kpc), and the phase of the Sun in the spiral density wave χ⊙ = ?193° ± 5°. The phase χ⊙ has been found to change noticeably with the mean age of the sample. Having analyzed these phase shifts, we have determined the mean value of the angular velocity difference Ω p ? Ω, which depends significantly on the calibrations used to estimate the individual ages of Cepheids. When estimating the ages of Cepheids based on Efremov’s calibration, we have found |Ω p ? Ω0| = 10 ± 1stat ± 3syst km s?1 kpc?1. The ratio of the radial component of the gravitational force produced by the spiral arms to the total gravitational force of the Galaxy has been estimated to be f r0 = 0.04 ± 0.01.  相似文献   

10.
Polarization observations of the H2O maser emission at 1.35 cm from the active region Orion KL were carried out at epoch 2011.7 on the Svetloe-Zelenchukskaya radio interferometer. The observational data have been processed on the correlator of the QUASAR network. Fragments of the structure have been identified; the line velocities and profile widths and the emission polarization have been determined. The component at the radial velocity V = 7.0 km s?1 has been taken as a reference one. Its effective size in the Gaussian approximation is 1.5 mas, the axial ratio is Major/Minor = 3.3, and the orientation is PA = 11°. The component V = 7.6 km s?1 corresponds to a bipolar outflow with an effective size of 6.2 mas, the axial ratio is Major/Minor = 5.3, and the orientation ?32°. The bipolar outflow is 10 mas away from the reference feature in the direction of 173°. The longitudinal velocity components of the NW and SE parts of the bipolar outflow in the local standard of rest are +0.15 and ?0.15 km s?1, respectively. The degrees of polarization of the emission from the reference feature (7.0 km s?1) and the bipolar outflow are m = 39 and 52%, respectively. The difference in polarization orientations of both components ?? ?? does not exceed 3°.  相似文献   

11.
Profiles of the UV semiforbidden lines of C III and Si III of RW Aur have been obtained with the HST/STIS. The C III profile shows two high velocity components at v = ± 170 km s?1 and a central one. The Si III profile is very broad (FWHM = 293 km s?1) and the high velocity components are unresolved. It is shown that the high velocity components are most probably produced in a rotating belt alike the detected in other sources of bipolar outflows. A radius between 2.7 R * and the corotation radius (6.1 R *) is derived and a log T e (K) ?4.7 and log n e(cm ?3) = 11.6 are estimated. The belt is clumpy and the most likely source of heating is local X-rays radiation, probably associated with the release of magnetic energy.  相似文献   

12.
Based on published sources, we have created a kinematic database on 220 massive (> 10 M ⊙) young Galactic star systems located within ≤3 kpc of the Sun. Out of them, ≈100 objects are spectroscopic binary and multiple star systems whose components are massive OB stars; the remaining objects are massive Hipparcos B stars with parallax errors of no more than 10%. Based on the entire sample, we have constructed the Galactic rotation curve, determined the circular rotation velocity of the solar neighborhood around the Galactic center at R 0 = 8kpc, V 0 = 259±16 km s?1, and obtained the following spiral density wave parameters: the amplitudes of the radial and azimuthal velocity perturbations f R = ?10.8 ± 1.2 km s?1 and f θ = 7.9 ± 1.3 km s?1, respectively; the pitch angle for a two-armed spiral pattern i = ?6.0° ± 0.4°, with the wavelength of the spiral density wave near the Sun being λ = 2.6 ± 0.2 kpc; and the radial phase of the Sun in χ ⊙ = ?120° ± 4°. We show that such peculiarities of the Gould Belt as the local expansion of the system, the velocity ellipsoid vertex deviation, and the significant additional rotation can be explained in terms of the density wave theory. All these effects decrease noticeably once the influence of the spiral density wave on the velocities of nearby stars has been taken into account. The influence of Gould Belt stars on the Galactic parameter estimates has also been revealed. Eliminating them from the kinematic equations has led to the following new values of the spiral density wave parameters: f θ = 2.9 ± 2.1 km s?1 and χ ⊙ = ?104° ± 6°.  相似文献   

13.
Polarization measurements of the H2O maser emission from the active region in Orion KL were carried out at epoch 2011?C2012 on the Svetloe-Zelenchukskaya radio interferometer. The bipolar outflow structure and polarized emission parameters have been determined. The emission from the components at v = 7.6 and 7.0 km s?1 dominates in the line profile; the relative contribution of the former component has increased. The velocity of the bipolar outflow ejector region is almost equal to that of the local standard of rest v LSR = 7.65 km s?1, while the velocity of the remote component is v = 7.0 km s?1. The emission from the bipolar outflow is observed at a distance up to 11 mas from the ejector. Its diameter does not exceed 0.3 mas. The outflow orientation in the plane of the sky is ?37°. The outflow velocity components along the line of sight differ by ??v = 0.3 km s?1. The polarization levels of the bipolar outflow and the remote component reach m = 62 and 39%, respectively.  相似文献   

14.
The statistical parallax technique is applied to a sample of 262 RRab Lyrae variables with published photoelectric photometry, metallicities, and radial velocities and with measured absolute proper motions. Hipparcos, PPM, NPM, and the Four-Million Star Catalog (Volchkov et al. 1992) were used as the sources of proper motions; the proper motions from the last three catalogs were reduced to the Hipparcos system. We determine parameters of the velocity distribution for halo [(U 0, V 0, W 0) = (?9±12, ?214 ±10, ? 10, ?16±7) km s ?1 and (σ U , σ V , σ W ) = (164±11, 105±7, 95±7) km s ?1] and thick-disk [(U 0, V 0, W 0) = (?16±8, ?41±7, ?18±5) km s ?1], and [(σ U , σ V , σ W ) = (53±9, 42±8, 26±5) km s ?1] RR Lyrae, as well as the intensity-averaged absolute magnitude for RR Lyrae of these populations: 〈M V 〉 = 0.77 ± 0.10 and 〈M V 〉 = +1.11 ± 0.25 for the halo and thickdisk objects, respectively. The metallicity dependence of the absolute magnitude of RR Lyrae is analyzed (〈M V 〉 = (0.76 ± 0.12) + (0.26 ± 0.26) · ([Fe/H]+1.6)=1.17+0.26 · [Fe/H]). Our results are in satisfactory agreement with the ?M V ?(RR)?[Fe/H]relation from Carney et al. (1992) (〈M V 〉(RR)=1.01+0.15·[Fe/H]) obtained by Baade-Wesselink's method. They provide evidence for a short distance scale: the LMC distance modulus and the distance to the Galactic center are 18.22±0.11 and 7.4±0.5 kpc, respectively. The zero point of the distance scale and the kinematic parameters of the RR Lyrae populations are shown to be virtually independent of the source of absolute proper motions used and of whether they are reduced to the Hipparcos system or not.  相似文献   

15.
We measured the radial velocity of the star θ1 Ori D from IUE spectra and used published observations. Based on these data, we determined the period of its radial-velocity variations, P=20.2675±0.0010 days, constructed the phase radial-velocity curve, and solved it by least squares. The spectroscopic orbital elements were found to be the following: the epoch of periastron passage Ep=JD 2430826.6±0.1, the system's center-of-mass velocity /Gg=32.4±1.0 km s?1, K=14.3±1.5 km s?1, Ω=3.3±0.1 rad, e=0.68±0.09, a1 sin i = 3 × 1010 km, and f1 = 0.0025M⊙. Twice the period, P=40.528±0.002 days, is also consistent with the observations.  相似文献   

16.
Based on the Ogorodnikov-Milne model, we analyze the proper motions of 95 633 red giant clump (RGC) stars from the Tycho-2 Catalogue. The following Oort constants have been found: A = 15.9 ± 0.2 km s?1 kpc?1 and B = ?12.0±0.2 km s?1 kpc?1. Using 3632 RGC stars with known proper motions, radial velocities, and photometric distances, we show that, apart from the star centroid velocity components relative to the Sun, only the model parameters that describe the stellar motions in the XY plane differ significantly from zero. We have studied the contraction (a negative K effect) of the system of RGC stars as a function of their heliocentric distance and elevation above the Galactic plane. For a sample of distant (500–1000 pc) RGC stars located near the Galactic plane (|z| < 200 pc) with an average distance of d = 0.7 kpc, the contraction velocity is shown to be Kd = ?3.5 ±0.9 km s?1; a noticeable vertex deviation, l xy = 9 · o 1 ± 0 · o 5, is also observed for them. For stars located well above the Galactic plane (|z| ≥200 pc), these effects are less pronounced, Kd = ?1.7 ± 0.5 km s?1 and l xy = 4 · o 9 ± 0 · o 6. Using RGC stars, we have found a rotation around the Galactic X axis directed toward the Galactic center with an angular velocity of ?2.5 ± 0.3 km s?1 kpc?1, which we associate with the warp of the Galactic stellar-gaseous disk.  相似文献   

17.
The results of quasi-simultaneous spectroscopic and photometric observations of a W UMatype eclipsing variable star AM Leo are presented. The observations were carried out with a 1.2-m telescope equipped with a high-resolution echelle spectrometer, and a telescope-reflector (D = 0.45m) of the Kourovka Astronomical Observatory of Ural Federal University. New values of semi-amplitudes of the radial velocity curves of the components, K1 = 109.6kms?1 and K2 = 252.4kms?1 and the systemic radial velocity V0 =-9.3 kms?1 are obtained, comparable to the data published in the literature. The semi-amplitude of the radial velocity curve of a more massive component K1 and the mass ratio of the components q = 0.412 appeared to be slightly smaller than the values obtained by other authors. An assumption wasmade that a possible reason of this is the presence of hot and/or cold spots on the surface of the components, shifting the effective center of brightness of the visible disk of the component with respect to its center of mass position. It was shown that the AM Leo light curve variations on the time scales of one and more days, registered within the photometric part of the study may be described by the choice of appropriate model of the spot structure.  相似文献   

18.
The T Tauri variable V1331 Cyg is characterized by an intensive emission spectrum, by signatures of a high rate of mass loss, and also by presence of a circular reflection nebula. According to these characteristics, the star can be considered as a possible pre-FUor star. Up to the present the photospheric spectrum of the star has not been recorded. In this work we analyze the high-resolution spectra of V1331 Cyg that were obtained by G.H. Herbig with the HIRES spectrograph at the Keck-1 telescope in 2004 and 2007. For the first time the numerous photospheric lines of the star have been detected and the spectral class has been estimated, viz., G7-K0 IV. It is revealed that the projection of the rotation velocity is lower than the width of instrumental profile (vsini < 6 km/s); this means that the angle between the stellar axis of rotation and the line of sight is small. The radial velocity of the star derived from the photospheric lines is RV = ?15.0 ± 0.3 km/s. The difference in radial velocities for 2004 and 2007 is lower than the measurement error. The photospheric spectrum is veiled considerably, but the amount of veiling is not the same in different lines. This depends on the line strength in the template spectrum of the G7 IV star: in the weakest lines (EW = 5–10 mÅ in the template spectrum) VF ≈ 1 and it increases up to 4–5 in stronger lines. The Hα and Hβ lines demonstrate classical P Cyg profiles, which testifies to an intensive wind with a maximal velocity of about 400 km/s. In addition, the emission lines of Fe II, Mg I and K I and of several other elements are accompanied by a narrow blue-shifted absorption at ?150...?250 km/s. The emission spectrum of V1331 Cyg is rich in the narrow (FWHM = 30–50 km/s) lines of neutral and ionized metals showing the excitation temperature T exc = 3800 ± 300 K. The stellar mass M* ≈ 2.8M ⊙ and radius R* ≈ 5R ⊙ are estimated.  相似文献   

19.
Currently available data on the field of velocities V r , V l , V b for open star clusters are used to perform a kinematic analysis of various samples that differ by heliocentric distance, age, and membership in individual structures (the Orion, Carina-Sagittarius, and Perseus arms). Based on 375 clusters located within 5 kpc of the Sun with ages up to 1 Gyr, we have determined the Galactic rotation parameters ω 0 = ?26.0 ± 0.3 km s?1 kpc?1, ω′0 = 4.18 ± 0.17 km s?1 kpc?2, ω″0 = ?0.45 ± 0.06 km s?1 kpc?3, the system contraction parameter K = ?2.4 ± 0.1 km s?1 kpc?1, and the parameters of the kinematic center R 0 = 7.4 ± 0.3 kpc and l 0 = 0° ± 1°. The Galactocentric distance R 0 in the model used has been found to depend significantly on the sample age. Thus, for example, it is 9.5 ± 0.7 and 5.6 ± 0.3 kpc for the samples of young (≤50 Myr) and old (>50 Myr) clusters, respectively. Our study of the kinematics of young open star clusters in various spiral arms has shown that the kinematic parameters are similar to the parameters obtained from the entire sample for the Carina-Sagittarius and Perseus arms and differ significantly from them for the Orion arm. The contraction effect is shown to be typical of star clusters with various ages. It is most pronounced for clusters with a mean age of ≈100 Myr, with the contraction velocity being Kr = ?4.3 ± 1.0 km s?1.  相似文献   

20.
A sample of classical Cepheids with known distances and line-of-sight velocities has been supplemented with proper motions from the Gaia DR1 catalogue. Based on the velocities of 260 stars, we have found the components of the peculiar solar velocity vector (U, V, W)⊙ = (7.90, 11.73, 7.39) ± (0.65, 0.77, 0.62) km s?1 and the following parameters of the Galactic rotation curve: Ω0 = 28.84 ± 0.33 km s?1 kpc?1, Ω′0 = ?4.05 ± 0.10 km s?1 kpc?2, and Ω″0 = 0.805 ± 0.067 km s?1 kpc?3 for the adopted solar Galactocentric distance R 0 = 8 kpc; the linear rotation velocity of the local standard of rest is V 0 = 231 ± 6 km s?1.  相似文献   

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