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1.
We present the analysis of the photometric and spectroscopic data obtained for comet C/2010 X1 (Elenin) when it was at a distance of 2.92 AU from the Sun. The observations were made at the prime focus of the 6-m BTA telescope with the SCORPIO focal reducer. The magnitude of the comet, measured in the R c -band with an 9?? aperture radius amounted to 16?8 ± 0?1. The computed dust production rate was estimated to be about 6 kg/s. The cometary coma manifested the emissions in the (0?C0) band of the CN molecule violet system, and a number of emission band heads of the C3 molecule. The gas production rate of the molecules is determined using the Haser model and amounts to 1.41 × 1024 and 4.20 × 1023 molecules per second for CN and C3, respectively. The ratio of gas production rates log[Q(C3)/Q(CN)] is equal to ?0.85, which is close to the mean value, determined for a significant number of comets. A normalized gradient of the cometary dust reflectivity, calculated for the 4430?C6840 ? spectral range amounts to 14.3 ± 1.2%. 相似文献
2.
A. V. Ivanova V. L. Afanasiev P. P. Korsun A. R. Baranskii M. V. Andreev V. A. Ponomarenko 《Solar System Research》2012,46(4):313-319
The results of the photometric observations of comet 29P/Schwassmann-Wachmann 1 are analyzed. The comet demonstrates substantial activity at heliocentric distances larger than 5 AU, i.e., outside the water ice sublimation zone. The CCD images of the comet were obtained in wideband R filters at the 6-meter telescope of the Special Astrophysical Observatory of the Russian Academy of Sciences (SAO RAS) and at the 2-meter Zeiss-2000 telescope of the Peak Terskol Observatory. The processing of the images with special digital filters allowed the active structures (jets) to be distinguished in the dust coma of the comet. With the cross-correlation method, the rotation period of the cometary nucleus was determined as 12.1 ± 1.2 and 11.7 ± 1.5 days for the observations taken in December 2008, and February 2009, respectively. The probable causes of the difference in the estimates of the rotation period of the cometary nucleus obtained by different authors are discussed. 相似文献
3.
We investigated comets active at large heliocentric distances using observations obtained at the 6-m BTA telescope (SAO RAS, Russia). Long-slit and photometric modes of the focal reducer SCORPIO were used. Two of the comets, 29P/Schwassmann-Wachmann 1 (SW1) and C/2002 VQ94 (LINEAR) were observed to be emission rich. Detection of CO+ and N+2 emissions in the comae of these comets is evidence that they were formed in the outer regions of the Solar System or in a pre-solar interstellar cloud in a low temperature environment with T?25 K. The ratio of N+2/CO+ is equal to 0.011 and 0.027 for SW1 and LINEAR, respectively. Comet LINEAR is the most distant object in the Solar System (7.332 AU) for which CO+ and N+2 are measured. The photometric maximum of the isolated CO+ coma in Comet LINEAR is shifted by 1.4 arcsec (7.44×103 km) relative to the photometric maximum of the dust coma. This shift deviates from the sunward direction by 63 degrees. 相似文献
4.
G. S. Kurbasova A. A. Korsun’ M. N. Rybalova 《Bulletin of the Crimean Astrophysical Observatory》2009,105(1):140-146
The view of the Earth’s polar motion as a completely deterministic process has been called into question in the past decades, because no long-term prediction can be made. At the same time, no fundamental restrictions currently exist in the problem of a long-term prediction of the Earth’s rotation. Determining the boundaries of predictability is related to identifying the regime of the Earth’s polar motion. IERS data for the period 1962–2007 have been used to study the regime of the Earth’s polar motion. Analysis of the plots of polhodes reveals peculiarities in the variations of the pole’s coordinates X and Y in certain intervals along the time axis. The data in the interval from 2003 to 2006 have been analyzed in greatest detail: a model for the Chandler and annual oscillations has been constructed and relations between the parameters of these oscillations have been determined; the shift of the instantaneous pole on the phase plane and the Poincare plane has been investigated. As a result, we have found features inherent in chaotic motion (intermittency) and calculated the period (32 years) of the possible repetitions of such anomalies, as confirmed by our analysis of the plots of polhodes. The intervals where the peculiarities in the motion of the Earth’s instantaneous pole manifest themselves are compared with the intervals of the inflections on the plots of variations in the length of the day (LOD). 相似文献
5.
The paper presents the results of dynamic simulation for the dust tail formation of comet C/1995 O1 (Hale-Bopp). To simulate
the dust tail, the trajectories of 2 × 106 dust particles were traced. The sizes, ejection moments, outflow directions and velocities of the dust particles were defined
by the Monte Carlo algorithm. The obtained three-dimensional tail was projected on the sky plane to compare it with the observed
images. The brightness distribution in the comet tail was fitted to similar model parameters for three different dates. According
to our model experiments, the observed tails could be formed by particles with sizes from 0.3 to 8.0 μm, ejection velocities
from 0.155 to 0.670 km/s, and power index of the exponential size distribution from −3.6 to −3.7. It is shown that the inclusion
of the particles fragmentation processes leads to a noticeable improvement of the simulation results. 相似文献
6.
P. P. Korsun 《Astronomische Nachrichten》1995,316(4):255-260
Spectroscopic observations of Comet P/Brorsen-Metcalf were made on August 9–13, 1989. Spatial profiles extracted from long-slit spectra were analyzed to determine the lifetimes of C3 and NH2 radicals and their parents, as well as the tailward acceleration of these radicals. In our investigations we used a Monte Carlo model. The average lifetime for C3 has been found to be 6.3 × 104 s and that for the parent of C3 to 6 × 103 s. The spatial profiles of C3 were almost symmetric and we need only 0.1 cm s−2 as the tailward acceleration. According to our simulations, C3H4 (allene) can be considered as the parent for C3. We obtained the average value 7.6 × 104 s for the lifetime of NH2 and 1.1 × 104 s for the lifetime of the NH2 parent. The tailward acceleration of NH2 was not more than 0.1 cm s−2. This result does not exceed the latest theoretical calculations of NH2 and NH3 lifetimes by a factor of 1.4. So, NH3 may be considered as a parent for NH2 in the atmosphere of P/Brorsen-Metcalf. 相似文献
7.
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
8.
We investigated three comets, which are active at large heliocentric distances, using observations obtained at the 6-m BTA telescope (SAO RAS, Russia) in the photometric mode of the focal reducer SCORPIO. The three comets, 29P/Schwassmann-Wachmann 1, C/2003 WT42 (LINEAR), and C/2002 VQ94 (LINEAR), were observed after their perihelion passages at heliocentric distances between 5.5 and 7.08 AU. The dust production rates in terms of Afρ was measured for these comets. Using the retrieved values, an average dust production rate was derived under different model assumptions. A tentative calculation of the total mass loss of the comet nucleus within a certain observation period was executed. We calculated the corresponding thickness of the depleted uppermost layer where high-volatile ices completely sublimated. The results obtained in our study strongly support the idea that the observed activity of Comet SW1 requires a permanent demolition of the upper surface layers. 相似文献
9.
10.
To explain the distinct transversal striae observed in the tail of comet C/2006 P1 (McNaught) near the perihelion, a dynamic
model for the formation of the dust tail of the comet has been developed. It is supposed that, on the surface of the nucleus,
there are three local active domains of the increased outflow of the material. Formation of the striated features is caused
by different rates of material outflow from the active areas depending on which side of the rotating nucleus, illuminated
or shadowed, these areas are located. It has been found that the period of the axial rotation of the comet is 21 h. 相似文献