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1.
Photoelectric observations of FW Monocerotis inU,B, andV filters have been discussed. The depths of the primary minimum inU BV colours are 2 . m 63, 2 . m 17 and 1 . m 76, respectively. No variation in the period has been found and its revised value is 3 . d 8735868.  相似文献   

2.
Photoelectric observations of WX Eridani inB andV filters have been discussed. The maximum magnitudes of the system areB=9 m .70 andV=9 m .46. TheB-V colours of the components are 0 m .16 and 0 m .80 for the primary and the secondary, respectively, while their spectral types are A5+K0. The period has been found to be constant and its revised value is 0d.823 270 76.  相似文献   

3.
Differences in magnitudes between the components of 874 double stars have been derived from visual estimates on several series of multi-exposure photographic plates. The plates were obtained with long focus refractors primarily for the purpose of determining the relative positions of double stars according to the well-known Hertzsprung method. Except for binaries with magnitude differences less than half a magnitude, plates were taken with objective gratings limiting the effective magnitude differences between the components to half a magnitude. Similar to what has been done in variable star work, it was found possible to estimate the magnitude difference to the nearest tenth from this material by visual inspection, using a seven power eyepiece. The internal mean error of a single estimate of a magnitude is ±0 m .064, while the external mean error of a single value in the catalogue based upon an average of three independent determinations is ±0 m .054. Comparisons with other photometric series of this type have been made. In particular the photoelectric series by Eggen (1963, 1966) and by Johnson (1953) show close agreements, with no systematic differences. The results will appear inPubl. U.S. Naval Obs., 2nd Series,18, Pt. V.  相似文献   

4.
The RS CVn-type eclipsing binary AR Lac has been observed in two colours,B andV, in 1978 and 1979. Several times of minima have been obtained during the observations and the new light elements have been calculated. The orbital period of the system was found to be decreasing with an amount of 14.6 s century–1.The light curves of the system obtained inB andV show a significant wave-like distortion outside eclipses. The amplitudes of the wave-like distortion inB andV are about 0 . m 09 and 0 . m 10 in 1978, and, 0 . m 12 and 0 . m 13 in 1979, respectively. The minima of the wave-like distortion have shifted with an amount of 0 . p 40 in one year, thus indicating the migration period of the wave-like distortion is about 2.5 yr.A noticeable variation of light during the totality of primary minimum has also been observed. This variation can be attributed to the distortion wave which has been moving towards decreasing phases.  相似文献   

5.
Photometric data inuvbyß system from 3713 stars is used to map the distribution of colour excesses up to 500 parsec from the Sun, producing diagrams for a series of layers aligned with the galactic plane. Individual clouds are detected, with a mean diameter of 6 parsecs, while cloud complexes have a mean diameter of 100 pc. From the maps it seems that the interstellar medium near the Sun presents regions of non-negligible extinction, while the Sun itself is enbedded in a diffuse cloud, or slightly off its border. The large scatter in the distribution ofE(b-) is confirmed, with a mean extinction ofA v=0 . m 38 up to 500 pc.  相似文献   

6.
B andV observations of the suspected variable BV 690 = NSV 04298 are reported. The star shows light variations with a period of ld.2400 and with amplitudes of 0m.27, 0m.36 and 0m.11 inV, B, andB-V respectively. The light curves show steeper rise than decline, and there is evidence for the presence of a bump in the descending branch around the phase of 0.35. From considerations of the period, spectral type, presence of the bump and high tangential velocity we conclude that BV 690 belongs to the BL Herculis class of Typen Cepheids  相似文献   

7.
The RS CVn-type eclipsing binary SZ Psc was observed in two coloursB andV, in 1981. The rate of change of the period was calculated using two different least-squares procedures. The amplitudes of the light variations at outside eclipses are 0 . m 181 and 0 . m 213 inB andV colours, respectively. The light curves of the system have been solved using a new approximation. The radius of the cooler component is only 82% of its Roche-radius and the system is detached one.  相似文献   

8.
Photometric observations of primary minimum inU, B, andV filters have been discussed. The amplitude of variation in all the three filters is 0 m .66. We do not find variations in the period and its revised value is 1d.0047115.  相似文献   

9.
Recurrent power series methods are particularly applicable to problems in celestial mechanics since the Taylor coefficients may be expressed by recurrence relations. However, as the number of Taylor coefficients increases as is often necessary because of accuracy requirements, the computing time grows prohibitively large. In order to avoid this unfavorable situation, Dr E. Fehlberg introduced in 1960 Runge-Kutta methods that use the firstm Taylor coefficients obtained by recursive relations, or some other technique.Optimalm-fold Runge-Kutta methods are introduced. Embedded methods of order (m+3)[m+4] and (m+4)[m+5] are presented which have coefficients that produce minimum local truncation errors for the higher order pair of solutions of the method, as well as providing a near maximum absolute stability region. It is emphasized that the methods are formulated such that the higher order pair of solutions is to be utilized. These optimal methods are compared to the existingm-fold methods for several test problems. The numerical comparisons show that the optimal methods are more efficient. It is stressed that these optimal methods are particularly efficient whenm is small.  相似文献   

10.
Power spectra of the 1979 solar differential observations (Bos, 1982) have been analyzed for evidence of intermediate-degreef-modes. A set of 19 intermediate-degreef-mode multiplets has been identified and classified based on more than 300 classified modes of oscillation. The angular degree of the multiplets ranges from 18 to 36. Them=0 eigenfrequency spectrum, measured with an accuracy of typically 0.01–0.02 Hz, was found to be on the average 10 Hz greater than that predicted by the standard solar model of Saio (1982). Rotational splitting effects up to fifth order inm were obtained. The multiplet fine structure that is linear inm was found to be consistent with the internal rotation curve obtained by Hillet al. (1986a). The multiplet fine structure that is described by terms that are cubic and fifth order inm were found to be consistent with the differential rotation curve of Hillet al. (1986b). The probability that this set of 19 Zeeman-like frequency patterns were obtained from a set of peaks randomly distributed in frequency was estimated to be 10–9. The effectiveness of the mode detection and classification program in this work has been established in part by observing the horizontal spatial properties of thef-mode eigenfunctions. One consequence obtained from the study of the horizontal spatial properties of the modes is the estimate, obtained observationally, of the number of correct mode identifications: these results indicate that 73±6% of the 374 modes are correctly classified.SCLERA is an acronym for Santa Catalina Laboratory for Experimental Relativity by Astrometry, a facility operated by the University of Arizona.  相似文献   

11.
Chandrasekhar's (1933) paper on rotational distortion of polytropes contained a perturbation term in the potential which was linear inv, the rotation parameter. The same paper, and subsequent papers by various authors, developed an analytic expression for the boundary also linear inv. The latter expression is equivalent to a two term Taylor series about the unperturbed boundary, and is in error by 12% near critical rotation, for a polytropic index 3.0. The boundary can be located directly from the functions representing density, potential, and the potential gradient. The boundary error by this procedure is 0.2% near critical rotation.  相似文献   

12.
Photometric observation of HR 1099 inV andB obtained on 18 nights between January and March 1977 is presented. The amplitude of the asymmetric light curve is found to be 0m.10±0m.004 both inV andB. On three occasions—namely, JD 2443164. 17, JD 2443176. 14 and JD 2443177.12—the star brightened by 0m.05. Four H spectrograms at 42 Å mm–1 dispersion were obtained during October–November 1978. The profile and equivalent width of H of 14 November, 1978 suggest a probable major outburst.Analysis of all available photometry shows that (1) the amplitude and shape of the light curve change in a few orbital periods, (2) the phase of the minimum light migrated towards decreasing orbital phase during the interval JD 2442720 to JD 2443000 and from JD 2443200, there is almost a linear increase of the phase of the minimum light and (3) the phase of the light minimum sometimes shows to and fro behaviour suggesting the migration of the wave is not taking place smoothly.  相似文献   

13.
As a preparation step to compute Jacobian elliptic functions efficiently, we created a fast method to calculate the complete elliptic integral of the first and second kinds, K(m) and E(m), for the standard domain of the elliptic parameter, 0 < m < 1. For the case 0 < m < 0.9, the method utilizes 10 pairs of approximate polynomials of the order of 9–19 obtained by truncating Taylor series expansions of the integrals. Otherwise, the associate integrals, K(1 − m) and E(1 − m), are first computed by a pair of the approximate polynomials and then transformed to K(m) and E(m) by means of Jacobi’s nome, q, and Legendre’s identity relation. In average, the new method runs more-than-twice faster than the existing methods including Cody’s Chebyshev polynomial approximation of Hastings type and Innes’ formulation based on q-series expansions. Next, we invented a fast procedure to compute simultaneously three Jacobian elliptic functions, sn(u|m), cn(u|m), and dn(u|m), by repeated usage of the double argument formulae starting from the Maclaurin series expansions with respect to the elliptic argument, u, after its domain is reduced to the standard range, 0 ≤ u < K(m)/4, with the help of the new method to compute K(m). The new procedure is 25–70% faster than the methods based on the Gauss transformation such as Bulirsch’s algorithm, sncndn, quoted in the Numerical Recipes even if the acceleration of computation of K(m) is not taken into account.  相似文献   

14.
DifferentialUBV observations, carried out in 1990 observing season, of a small amplitude (0 . m 15 inV andB) W UMa system LS Del = HD 199497 are presented. Wavelength-dependent light variations from cycle to cycle indicate that the system is in a very active phase, probably due to magnetic flare activity or mass transfer in the system. An analysis of the minima times indicate a probable secular increase of the photometric period which requires a mass transfer from less massive to more massive component. If this is true then the reverse-algol model by Liuet al. (1988) for this system would not be valid.  相似文献   

15.
Sinusoidal variations in bothV - andB-bands were detected in some flare stars of the UV Ceti type outside of flares. This detection has confirmed the light variation detection in Johnson'sV -band in EV Lac at quiet-state luminosity by Pettersen (1980) with a cyclic period equals about 4 . d 378 and an amplitude of about 0 . m 07. An interpretation of these short cyclic periods is that they are due to intensity modulations from a photospheric spot group as a result of stellar equatorial rotations. A short period of 14 days with an amplitude of 0 . m 099 was detected inB-band in AD Leo. For the two flare stars, BD+55° 1823 and DO Cep in bothV- andB-bands, cyclic periods of more than 3 days and less than 17 days with amplitudes more than 0 . m 090 and less than 0 . m 250 have been registered. A significant contribution has been found in the flare star EV Lac in bothV- andB-bands at its quiescent-state luminosity where the detected cyclic periods are agreed with that which was detected by Pettersen (1980) in the same flare star in Johnson'sV-band, about 4 days. Furthermore, we found the same cyclic period in the colour index,B - V (about 4 days) which strengthens starspot phenomenon. This colour index period could not be detected by Pettersen (1980).  相似文献   

16.
Light curves have been constructed for a number of model astroids as represented by three series of triaxial ellipsoids (one almost prolate, one almost oblate and one in between). The light curves have maximumpossible amplitudes (m) ranging from 0m.1 to 1.0. The case m=0m.7 is illustrated in some detail. Quite complicated patterns of motion are shown at times to lead to simplelooking light curves for the prolate models. It is argued that models of this latter type are likely to be over-represented in any sampling of asteroidal light curves because of simple selection effects.  相似文献   

17.
Experiments based on multi-source radio occultation measurements of the circumsolar plasma at R∼4.0−70R S were carried out during 1997 – 2008 to locate the inner boundary of the solar-wind transonic transition region, R in. The data obtained were used to correlate the solar-wind stream structure and magnetic fields on the source surface (R=2.5R S) in the solar corona. The method of the investigation is based on the analysis of the dependence R in=F(|B R|) in the correlation diagrams, where R in is the inner boundary of the solar-wind transition region and |B R| is the intensity of the magnetic field at the source surface. On such diagrams, the solar wind is resolved into discrete branches, streams of different types. The analysis of the stream types using a continuous series of data from 1997 to 2008 allowed us to propose a physical criterion for delimiting the epochs in the current activity cycle.  相似文献   

18.
A quantitative definition of limiting magnitude for stellar photographs is proposed, together with a method of measurement employing a Racine prism. Limiting magnitudes inU, B andV for the Isaac Newton telescope at Herstmonceux derived from a total of 72 prime focus photographs are presented and the results correlated with the size of the photographed image. The limiting magnitude for an extrapolated value of the seeing of 1 isB=22m.0, in good agreement with a value obtained by scaling the limiting magnitudes of the 200 inch telescope.  相似文献   

19.
The aim of the present paper is to deduce relations between the integral transformsA 2m, B2m,andF 1,2 of the light curves of eclipsing binary systems. The integral transformsA 2m, B2m,andF 1,2 have been related to one another by means of finite or rapidly converging infinite summations obtained by integrations of the series expansions of trigonometric functions.  相似文献   

20.
A new type of approximation is proposed to evaluate Fourier series with a great many terms. It combines Fourier series and Chebychev polynomials to represent time series over a finite time interval. On one side, the high frequencies are approximate multiples of a basic frequency to represent short periodic terms; on the other side, the slowly variable functions of the time, on a given interval, which contain terms with long periods, are approximated by Chebychev polynomials. Application is made in case of the Lunar Theory ELP which contains about 30 000 trigonometric terms. The computing time necessary to evaluate coordinates is very much reduced when we give to series the intermediary representation inF-T form, as compared to a direct substitution of the time in the arguments.One shows also on a numerical example, that the Fourier-Chebychev approximation smoothly degrades outside its range of representation.Bureau des Longitudes. Equipe de Recherche Associée au CNRS  相似文献   

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