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1.
N. O. Miller 《Solar System Research》2011,45(4):342-353
The work studies the Chandler component of polar motion, obtained from variations in the Pulkovo latitude over 170 years (1840–2009).
To extend the time series of variations in the Pulkovo latitude back into the past until 1840, we used the first Pulkov observations
on the basis of the Reynolds transit instrument in the prime vertical and on the basis of large vertical Ertel circle. We
employed different methods of analysis of nonstationary time series, such as wavelet analysis, methods of bandpass filtering,
singular spectral analysis, and Fourier and Hilbert transforms. Changes in the Pulkovo latitude from 1904–2006, as inferred
from ZTF-135 observations and as calculated from international data, were compared. It was shown that time changes in the
amplitude and phase of Chandler polar motion can be studied based on long-term observation time series of latitude at a single
observatory, even if these observation records have gaps. We were the first to study the changes in the Chandler wobble for
that long time series of variations in the Pulkovo latitude with the help of different methods. The long observation record
and the methods of analysis of nonstationary time series had allowed us to identify two similar structures, both well apparent
during the periods of 1845–1925 and 1925–2005 in the time variations of phase and amplitude. The presence of this structure
indicates that low-frequency regularities may be present in the Chandler polar motion, and one of the manifestations of this
may be the well known feature in the region of 1925. The superimposed epoch method was used to estimate the period of variations
in the amplitude with a simultaneous change of phase of this oscillation, which was found to be 80 years. In addition, advantages
of singular spectral analysis for studying the long-period time series with involved structure are demonstrated. 相似文献
2.
T. P. Kiseleva I. S. Izmailov O. A. Kalinichenko T. A. Vasilieva 《Solar System Research》2010,44(1):60-67
The results of the reduction, investigation, and comparison of the photographic observations of the major Saturnian satellites
and CCD observations with an ST6 CCD camera obtained at the 264nch Pulkovo refractor in 1995–2007 are presented. A comparison
of the observational results with the TASS 1.7 theory of motion of the Saturnian satellites has served as the basis for investigating
and comparing the series of observations. The period-averaged (O-C) residuals and observational errors have been calculated.
A comparison of the series of CCD and photographic observations has shown the same external accuracy of the observations at
a higher internal accuracy of the CCD observations than that of the photographic ones. A comparison of the Pulkovo results
with those of other authors has shown them to be close in accuracy. The accuracy of the theory has been estimated by comparing
simultaneous (on the same night) CCD and photographic observations. The errors of the observations and the theory have been
found from this comparison to be the following: 0.081“ and 0.067” for the observations and 0.077“ and 0.115” for the theory
(inxandy, respectively). An analysis of the dependence of (O-C)x,y for three satellites (the sixth, seventh, and eighth) on the satellite positions in Saturn-centered orbits has revealed systemat
ic deviations for the seventh satellite in both coordinates. The positions of Saturn have been determined from satellite observations
without measuring its images on photographic plates with accuracies of 0.121“ and 0.105” in right ascension and declination,
respectively. 相似文献
3.
4.
A. A. Korsun’ 《Kinematics and Physics of Celestial Bodies》2016,32(2):100-103
The aim of this article is to draw attention to the priority of the well-known astronomer and geophysicist, member of the Academy of Sciences of Ukraine A.Ya. Orlov (1880–1954) in the determination of the following parameters describing the secular motion of the earth’s poles: speed (4 mas/year) and direction (69° west). These results (1954) are based on the astronomical observations from 1900 to 1950 with zenith telescopes at international latitude stations. Orlov is well known in the world astronomical community as the founder of the Poltava Gravimetric Observatory, the Main Astronomical Observatory, and the national research school of global geodynamics. However, his pioneering work on secular polar motion is little known worldwide. At present, Orlov’s estimates for secular polar motion have been verified by century-long observations (1900–2012) obtained with different telescopes at many observatories worldwide and by different, both astronomical and space-based, methods (LLS, VLBI, GNSS, etc.). 相似文献
5.
Results from an analysis of a forty year series of photographic observations of the binary star 61 Cyg on the 26 inch refractor
at the Pulkovo Observatory are presented. The orbit is constructed and the sum of the masses of the components is determined
from the relative positions of the components. A study of the individual motions of the components of 61 Cyg relative to the
surrounding stars yields their mass ratio and the masses of the main and secondary components, 0.74 and 0.46 solar masses,
respectively. The relative motion of the components is found to have a fluctuating component with a period of 6.5 years which
may be caused, in particular, by the presence in the system of a dark, low-mass companion.
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Translated from Astrofizika, Vol. 49, No. 3, pp. 453–465 (August 2006). 相似文献
6.
The spectrophotometric temperatures of five Mira-type variable stars are determined using observations in the Pulkovo spectrophotometric
data base in the range from 320–1080 nm. All the resulting temperatures are below the effective temperatures of stars in the
corresponding subclasses. Near the brightness maximum, the temperatures are found to be lower with increasing separation in
time from the maximum.
__________
Translated from Astrofizika, Vol. 50, No. 3, pp. 415–426 (August 2007). 相似文献
7.
Astrometric CCD observations of 1123 stars with large proper motions (μ > 300 mas yr−1) from the LSPM (I/298) catalog in the declination zone +30°–+70° have been carried out with the Pulkovo normal astrograph
since 2006. The observational program includes mostly stars that previously have not entered into high-accuracy projects to
determine the proper motions. Our studies are aimed at determining new proper motions of fast stars in the HCRF/UCAC3 system
and searching for stars with invisible companions in the immediate Galactic neighborhoods of the Sun. Having analyzed about
10 000 CCD frames, we have obtained the equatorial coordinates of 414 program stars in the HCRF/UCAC3 system at an accuracy
level of 10–50 mas and determined their new proper motions. To derive the proper motions, we have used the data from several
star catalogs and surveys (M2000, CMC14, 2MASS, SDSS) as early epochs. The epoch differences range from 5 to 13 years (on
average, about 10 years); the mean accuracy of the derived proper motions is 4–5 mas yr−1. For 70 stars, we have revealed significant differences between the derived proper motions and those from the LSPM and I/306A
catalogs (these proper motions characterize the mean motion of the photocenter in 50 years or more). Apart from systematic
errors, these differences can result from the existence of invisible components of the program stars. 相似文献
8.
E. A. Grosheva 《Astrophysics》2006,49(3):397-404
The visual binary star ADS 15571 has been observed with the 26″ refractor at Pulkovo since 1960. Periodic perturbations in
the relative motion of the components are studied in this paper. The visible motion of the component B was resolved into orbital
motion of the barycenter relative to component A and an elliptical motion of the photocenter relative to the barycenter. The
visible ellipse of the photocenter motion is used to determine the elements of the orbit by the direct geometric method of
A. A. Kiselev and estimate the perturbing mass. The minimum mass of the invisible companion is 0.62 M⊙.
__________
Translated from Astrofizika, Vol. 49, No. 3, pp. 467–474 (August 2006). 相似文献
9.
A series of daytime observations of the Sun and major planets are obtained at the mountain astronomical station of the Pulkovo
Observatory using the Ertel-Struve meridian instruments. A series of declinations of Solar System bodies and major planets
includes 4057 positions and that of right ascensions of Solar System bodies comprising 2057 positions. Based on the joint
processing of observations of the Sun, Mercury, Venus, and Mars obtained with the Ertel-Struve vertical circle and large transit
instrument, the orientation elements of the DE200/LE200 dynamic coordinate system, namely, a correction for the right ascensions
of FK5 stars ΔA = +0.127″ ± 0.033″, a correction for declinations of FK5 stars ΔD = +0.056″ ± 0.011″, a correction for the ecliptic inclination Δɛ = −0.044″ ± 0.012″, and a correction for the average longitude
of the Sun ΔL = −0.083″±0.035″, are determined with respect to the stellar coordinate system. 相似文献
10.
I. S. Izmailov M. L. Khovricheva M. Yu. Khovrichev O. V. Kiyaeva E. V. Khrutskaya L. G. Romanenko E. A. Grosheva K. L. Maslennikov O. A. Kalinichenko 《Astronomy Letters》2010,36(5):349-354
We present the results of 3489 astrometric observations for 361 visual double stars performed in 2003–2007 with the 26-inch
refractor of the Pulkovo Observatory. The angular separations between the components (ρ) and the position angles (θ) are given. The errors in these quantities are, on average, 0″.009 for ρ and 0°.40/ρ for θ, where ρ is the separation in arcseconds. 相似文献
11.
E. Y. Aleshkina V. V. Kupriyanov A. V. Devyatkin I. A. Vereshchagina V. Yu. Slesarenko V. N. L’vov S. D. Tsekmeyster 《Solar System Research》2011,45(1):34-42
Near real time astrometric and photometric observations of the asteroid 2008 TC3, discovered 19 hours before it fell to Earth
in the area of northern Sudan, were conducted on the night of October 6–7, 2008, using an automated telescope ZA-320M of the
Pulkovo Observatory. In the interval of 4 h, 270 observations in the integral band of the telescope were performed, which
was about one-third of all global observations of the asteroid. Based on the analysis of all cases, physical parameters of
the asteroid were assessed. The estimates of the absolute magnitude of the asteroid (M
V = 30.6 ± 0.4 μm), its size (4.8 ± 0.8 m), and weight (131 ± 5 t) were obtained. A frequency analysis of the observational
series was conducted, which helped to detect the periodicity in the brightness variation of the asteroid. The elements of
the heliocentric orbit of the asteroid were refined. The trajectory of the asteroid, taking into account the atmospheric drag
and nonsphericity of the Earth, was simulated. 相似文献
12.
R. P. Kane 《Solar physics》2008,249(2):355-367
The 12-month running means of the conventional sunspot number Rz, the sunspot group numbers (SGN) and the frequency of occurrence of Coronal Mass Ejections (CMEs) were examined for cycle
23 (1996 – 2006). For the whole disc, the SGN and Rz plots were almost identical. Hence, SGN could be used as a proxy for Rz, for which latitude data are not available. SGN values were used for 5° latitude belts 0° – 5°, 5° – 10°, 10° – 15°, 15° – 20°,
20° – 25°, 25° – 30° and > 30°, separately in each hemisphere north and south. Roughly, from latitudes 25° – 30° N to 20° – 25°
N, the peaks seem to have occurred later for lower latitudes, from latitudes 20° – 25° N to 15° – 20° N, the peaks are stagnant or occur slightly earlier, and then from latitudes 15° – 20° N to 0° – 5° N, the peaks seem to have occurred again later for lower latitudes. Thus, some latitudinal migration is suggested, clearly in the northern hemisphere, not very clearly
in the southern hemisphere, first to the equator in 1998, stagnant or slightly poleward in 1999, and then to the equator again
from 2000 onwards, the latter reminiscent of the Maunder butterfly diagrams. Similar plots for CME occurrence frequency also
showed multiple peaks (two or three) in almost all latitude belts, but the peaks were almost simultaneous at all latitudes,
indicating no latitudinal migration. For similar latitude belts, SGN and CME plots were dissimilar in almost all latitude
belts except 10° – 20° S. The CME plots had in general more peaks than the SGN plots, and the peaks of SGN often did not match
with those of CME. In the CME data, it was noticed that whereas the values declined from 2002 to 2003, there was no further
decline during 2003 – 2006 as one would have expected to occur during the declining phase of sunspots, where 2007 is almost
a year of sunspot minimum. An inquiry at GSFC-NASA revealed that the person who creates the preliminary list was changed in
2004 and the new person picks out more weak CMEs. Thus a subjectivity (overestimates after 2002) seems to be involved and
hence, values obtained before and during 2002 are not directly comparable to values recorded after 2002, except for CMEs with
widths exceeding 60°. 相似文献
13.
14.
Some results of the photographic observations of double stars with 65 cm refractor of Pulkovo observatory are presented. We use the apparent motion parameters (AMP) method which allows to determine the orbits and to carry out the dynamical investigation of wide binaries on the basis of a short arc of their orbital motion. We have determined more than 40 orbits for wide pairs and also the sum of masses and in some cases—the mass-ratio of components. The references to our works and the basic results of observations are contained in Kisselev et al. [2004. Catalogue of relative positions of visual double stars made on the observations with 26″ refractor of Pulkovo observatory. Strassbourg, I/297]. We apply two ways of revealing the hidden mass of our stars, namely: revealing of possible perturbations from comparison of observational and calculated positions using differences O-C (for instance, perturbations in the orbital motion of ADS 15571) and also by means of comparison of the sum of the masses obtained by us and the sum of the masses obtained by means of the mass-luminosity relation. An excess of masses of about 1-3 solar masses is detected for binaries: ADS 497, ADS 8450 and ADS 10329 by means of last method.The estimations of the masses for some binaries are discussed. Also we justify the necessity of precise parallaxes and relative radial velocities of stars, which could be measured by space telescopes such as the GAIA as the additional parameters for determination of orbits of binaries. 相似文献
15.
We have analysed the observations of Solar Ca+K daily plage area for the period 1951-1977 to find evidence for the existence of short period (around 12–13 days) variation
in the data. We divided the data in three groups—two corresponding to 10–20‡N and 10–20‡S latitude belts, and one corresponding
to the total plage area—and used the power spectrum and autocorrelation techniques for the analysis. Both the techniques clearly
show the 27-day periodicity due to solar rotation modulation in all the sets. A 12–13 day periodicity is seen in only 3, out
of a total of 57 data sets when autocorrelation technique is used. A generally weak peak around 12–13 days is, however, seen
in the power spectrum of all the data sets. The relative power in the 12–13 day peak is found to be significantly higher in
those three data sets where the autocorrelation also shows this periodicity. On these two epochs the sunspot area distribution
showed the existence of two distinct active longitudes separated by about 140–170 degrees. This seems to be the cause for
the existence of a periodicity around 12–13 days in the autocorrelation and enhancement in the relative power of the 12–13
days peak in the power spectrum of these two epochs 相似文献
16.
O. S. Gopasyuk 《Kinematics and Physics of Celestial Bodies》2010,26(5):242-248
Torsional oscillations of seven single spots are studied based on the observations of the longitudinal magnetic field and
the field of radial velocities in the photospheric Fe I λ 525.3 nm line. The periods of umbra and penumbra oscillations are
2.2–7.1 and 3.3–7.7 days, respectively. The spots at a greater solar latitude are characterized by a longer period of oscillations
and a smaller axial strength of the magnetic field. The periods of umbra and penumbra oscillations increase with an increase
in the period and amplitude of the sunspot umbra oscillations. The obtained results can point to a unitary mechanism of torsional
oscillations of umbra and penumbra of single spots and a connection of these oscillations with the differential rotation of
the Sun. 相似文献
17.
Sanjay Kumar S. Priyadarshi S. Gopi Krishna A. K. Singh 《Astrophysics and Space Science》2012,339(1):165-178
The paper is based on the ionospheric variations in terms of vertical total electron content (VTEC) for the low solar activity
period from May 2007 to April 2009 based on the analysis of dual frequency signals from the Global Positioning System (GPS)
satellites recorded at ground stations Varanasi (Geographic latitude 25°16′ N, Longitude 82°59′ E), situated near the equatorial
ionization anomaly crest and other two International GNSS Service (IGS) stations Hyderabad (Geographic latitude 17°20′ N,
longitude 78°30′ E) and Bangalore (Geographic latitude 12°58′ N, longitude 77°33′ E) in India. We describe the diurnal and
seasonal variations of total electron content (TEC), and the effects of a space weather related event i.e. a geomagnetic storm
on TEC. The mean diurnal variation during different seasons is brought out. It is found that TEC at all the three stations
is maximum during equinoctial months (March, April, September and October), and minimum during the winter months (November,
December, January and February), while obtaining intermediate values during summer months (May, June, July and August). TEC
shows a semi-annual variation. TEC variation during geomagnetic quiet as well as disturbed days of each month and hence for
each season from May 2007 to April 2008 at Varanasi is examined and is found to be more during disturbed period compared to
that in the quiet period. Monthly, seasonal and annual variability of GPS-TEC has been compared with those derived from International
Reference Ionosphere (IRI)-2007 with three different options of topside electron density, NeQuick, IRI01-corr and IRI 2001.
A good agreement is found between the GPS-TEC and IRI model TEC at all the three stations. 相似文献
18.
We applied special data-processing algorithms to the study of long-period oscillations of the magnetic-field strength and
the line-of-sight velocity in sunspots. The oscillations were investigated with two independent groups of data. First, we
used an eight-hour-long series of solar spectrograms, obtained with the solar telescope at the Pulkovo Observatory. We simultaneously
measured Doppler shifts of six spectral lines, formed at different heights in the atmosphere. Second, we had a long time series
of full-disk magnetograms (10 – 34 hour) from SOHO/MDI for the line-of-sight magnetic-field component. Both ground- and space-based
observations revealed long-period modes of oscillations (40 – 45, 60 – 80, and 160 – 180 minutes) in the power spectrum of
the sunspots and surrounding magnetic structures. With the SOHO/MDI data, one can study the longer periodicities. We obtained
two new significant periods (> 3σ) in the power spectra of sunspots: around 250 and 480 minutes. The power of the oscillations in the lower frequencies is
always higher than in the higher ones. The amplitude of the long-period magnetic-field modes shows magnitudes of about 200 – 250 G.
The amplitude of the line-of-sight velocity periodicities is about 60 – 110 m s−1. The absence of low-frequency oscillations in the telluric line proves their solar nature. Moreover, the absence of low-frequency
oscillations of the line-of-sight velocity in the quiet photosphere (free of magnetic elements) proves their direct connection
to magnetic structures. Long-period modes of oscillation observed in magnetic elements surrounding the sunspot are spread
over the meso-granulation scales (10″ – 12″), while the sunspot itself oscillates as a whole. The amplitude of the long-period
mode of the line-of-sight velocity in a sunspot decreases rapidly with height: these oscillations are clearly visible in the
spectral lines originating at heights of approximately 200 km and fade away in lines originating at 500 km. We found a new
interesting property: the low-frequency oscillations of a sunspot are strongly reduced when there is a steady temporal trend
(strengthening or weakening) of the sunspot’s magnetic field. Another important result is that the frequency of long-period
oscillations evidently depends on the sunspot’s magnetic-field strength. 相似文献
19.
Heikki Nevanlinna 《Solar physics》2004,224(1-2):395-405
We have compiled archived geomagnetic observations from the Helsinki magnetic observatory as well as visual sightings of auroral
occurrence in Finland. The magnetic database comprises about 2 000 000 observations of H- and D-components measured during 1844–1909 with time resolution of 10 min to 1 h. In addition, magnetic observations carried out
in the First and Second Polar Years in Finland have been recompiled. Magnetic activity indices (three-hour K-and daily Ak-figures) have been derived from the magnetic observations. Comparisons between the Finnish indices and simultaneous global
aa-index (starting in 1868) show a good mutual correlation. The Helsinki activity index series can be used as a (pseudo) extension
of the aa-index series for about two solar cycles 1844d –1868. On the annual level the correlation coefficient is about 0.9 during
the overlapped time interval 1868–1897. The auroral database consists of about 20 000 single observations observed in Finland
since the year 1748. The database of visual auroras has been completed by auroral occurrence (AO) index data derived from
the Finnish all-sky camera recordings during 1973 –1997 at several sites in Lapland. The AO-index reveals both spatial and
temporal variations of auroras from diurnal to solar cycle time scales in different space weather conditions. 相似文献
20.
The evolution of a large-amplitude disturbance at cloud level in Jupiter's 24° N jet stream in 1990 is used to constrain the vertical structure of a realistic atmospheric model down to the 6 bar pressure level. We use the EPIC model (Dowling et al., 1998, The explicit planetary isentropic-coordinate (EPIC) atmospheric model, Icarus 132, 221-238) to perform long-term, three-dimensional, nonlinear simulations with a series of systematic variations in vertical structure and find that the details of the 1990 disturbance combine with the characteristics of the 24° N jet, the fastest on Jupiter, to yield a tight constraint on the solution space. The most important free parameters are the vertical dependence of the zonal-wind profile, and the thermal structure, below the cloud tops (p>0.7 bar) at the jet's central latitude. The temporal evolution of the disturbed cloud patterns, which spans more than 2 years, can be reproduced if the jet peak reaches ∼180 ms−1 at the cloud level and increases to ∼210 ms−1 at 1 bar and up to ∼240 ms−1 at 6 bar; the observations were not reproduced for other configurations investigated. This trend is consistent with that measured by the Galileo Probe at 7° N; the implication is that this jovian jet extends well below the solar radiation penetration level situated near the 2 bar level. 相似文献