共查询到20条相似文献，搜索用时 21 毫秒
1.
Kelsey D. Hargrove Michael S. Kelley Humberto Campins Javier Licandro Josh Emery 《Icarus》2012,221(1):453-455
We find a clear diversity in the 3 μm and 10 μm features of three Cybele asteroids: (107) Camilla, (121) Hermione, and (65) Cybele. (121) Hermione exhibits a “check-like” 3 μm feature, which may be attributed to OH-dominated minerals and (107) Camilla shows a rounded “bowl” like feature closer to that of (65) Cybele, which may be attributed to H2O-dominated minerals. The 10 μm features of these three asteroids are also different from each other. 相似文献
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D. Giaretta 《Astrophysics and Space Science》1979,63(2):379-387
Calculations by Penstonet al. (1969) of the mass distribution of interstellar clouds are reexamined in the light of Hobbs's data on the relationship between N(Caii) and N(H). The mass spectrum is calculated using two different sets of simple assumptions. Two possible explanations of the quadratic dependence of N(Ki) on N(H) are briefly examined. 相似文献
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R.P. Kane 《Planetary and Space Science》2010,58(3):392-400
In cycle 23 for geomagnetic storms of ?Dst(min) >50 nT, the plot of ?Dst(min) versus ?Bz(min) for the low ?Bz(min) range 0–10 nT showed erratic variation in Dst(min), (correlation 0.19). Even for ?Bz(min) range 10–20 nT, ?Dst(min) values had considerable scatter (correlation 0.57). For ?Bz(min).>20 nT, the relationship was good (correlation 0.82). For the whole range ?Bz(min) 0–50 nT, the correlation was high (0.88). Thus, if ?Bz(min) is very large (～20 nT), large ?Dst(min) occurs but in a wide range of 100–500 nT. 相似文献
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H. Scholl 《Celestial Mechanics and Dynamical Astronomy》1971,4(2):250-252
An analysis of the observations of the minor planets (153) Hilda, (279) Thule and (334) Chicago yields the following values for the reciprocal mass of Jupiter: (153) Hilda 1047.378±0.019, (279) Thule 1047.347±0.023, (334) Chicago 1047.325±0.010. A possible error in the mass of Saturn that might affect these results is discussed.Presented at IAU Colloquium No. 9, The IAU System of Astronomical Constants, Heidelberg, Germany, August 12–14, 1970. 相似文献
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R. Wachter J. Schou M. C. Rabello-Soares J. W. Miles T. L. Duvall Jr. R. I. Bush 《Solar physics》2012,275(1-2):261-284
We describe the imaging quality of the Helioseismic and Magnetic Imager (HMI) onboard the Solar Dynamics Observatory (SDO) as measured during the ground calibration of the instrument. We describe the calibration techniques and report our results for the final configuration of HMI. We present the distortion, modulation transfer function, stray light, image shifts introduced by moving parts of the instrument, best focus, field curvature, and the relative alignment of the two cameras. We investigate the gain and linearity of the cameras, and present the measured flat field. 相似文献
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Results of the first polarimetric observations of Centaurs (5145) Pholus and (10199) Chariklo, and new observations of (2060) Chiron are presented together with the estimates of their absolute magnitudes. Observations were carried out at the 8 m ESO Very Large Telescope in 2007-2008. They revealed noticeable negative polarization in the phase-angle range 0.5-4.4° with a minimum varying from −1% to −2.1% in the R band. All three objects show diverse polarization phase-angle behaviour, each distinctly different from that of transneptunian objects. We found evidence of surface heterogeneity for Chariklo while Chiron and Pholus appear to have rather homogeneous surfaces. Polarization phase behaviours of Chiron and Pholus are significantly different from any other Solar System bodies studied so far. A shift of negative polarization minima toward small phase angles seems to be a characteristic feature of polarization properties of Centaurs. Presence of a small amount of water frost on a dark surface is considered as one of the possible ways to explain these properties. 相似文献
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J. Schou J. M. Borrero A. A. Norton S. Tomczyk D. Elmore G. L. Card 《Solar physics》2012,275(1-2):327-355
As part of the overall ground-based calibration of the Helioseismic and Magnetic Imager (HMI) instrument an extensive set of polarimetric calibrations were performed. This paper describes the polarimetric design of the instrument, the test setup, the polarimetric model, the tests performed, and some results. It is demonstrated that HMI achieves an accuracy of 1% or better on the crosstalks between Q, U, and V and that our model can reproduce the intensities in our calibration sequences to about 0.4%. The amount of depolarization is negligible when the instrument is operated as intended which, combined with the flexibility of the polarimeter design, means that the polarimetric efficiency is excellent. 相似文献
8.
Three selected asteroids, numbered 58, 360 and405, were observed during 2000at Yunnan Observatory, China. Thenew lightcurves are presented inthis paper. The synodic period of (58)Concordia is estimated as 9.90 ± 0.01hfor the first time. The synodic period of (405) Thia derived from ourobservation is 9.96 ± 0.01h, which is slightly different from the previousresult. For 360, we obtained the synodic period of 6.18 ± 0.02h which isconsistent with previous values. Additionally, the BV and UB-colourindexes for the three asteriods were also determined. 相似文献
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It is pointed out that the relation between the Sun's geocentric diameter and the so-called drift time observed on the Earth's surface does not depend on topocentric data (distance, declination, parallax, refraction), but only on the geocentric values of distance, declination, and variation of right ascension. 相似文献
10.
GERHARD SCHMIDT 《Meteoritics & planetary science》1997,32(6):761-767
Abstract— Seven large (10 g) impact melt rock samples from boreholes from the Boltysh impact crater (Ukraine) and six samples from the East Clearwater crater (Canada) were analyzed for Os, Ir, Ru, Rh, Pd, Re and Au by the nickel sulfide technique in combination with neutron activation. Earlier analyses of Clearwater East impact melt rocks have shown that they are strongly enriched in Ir, Os, Pd and Re. In this work, I confirm earlier findings and demonstrate similarly high enrichments of Rh and Ru. The average Os/Ir, Ru/Ir, Pd/Ir, Rh/Ir and Ru/Rh ratios of the melt rock samples from Clearwater East are CI-chondritic and yield an average Ir content of 25.2 ± 6.5 ng/g relative to an average upper crust concentration of 0.03 ± 0.02 ng/g Ir. The amount of meteoritic component corresponds to 4 to 7% of a nominal CI component for Clearwater East. The impact melt rock samples from a bore hole from Boltysh are low in Ir with an average of 0.2 ± 0.1 ng/g. The CI-normalized abundances increase from the refractory to the more volatile siderophile elements (Os < Ir < Ru < Rh ～ Pd ～ Au ～ Ni ～ Co). Because of the low Ir anomaly and uncertainties in making corrections (correlations are weak) for indigenous siderophile elements, no clear projectile assignment can be made. 相似文献
11.
P.T. Timbie G.S. Tucker P.A.R. Ade S. Ali E. Bierman E.F. Bunn C. Calderon A.C. Gault P.O. Hyland B.G. Keating J. Kim A. Korotkov S.S. Malu P. Mauskopf J.A. Murphy C. O&#x;Sullivan L. Piccirillo B.D. Wandelt 《New Astronomy Reviews》2006,50(11-12):999
We provide an overview of a mission concept study underway for the Einstein Inflation Probe (EIP). Our study investigates the advantages and tradeoffs of using an interferometer (EPIC) for the mission. We also report on the status of the millimeter-wave bolometric interferometer (MBI), a ground-based pathfinder optimized for degree-scale CMB polarization measurements at 90 GHz. 相似文献
12.
《天文和天体物理学研究(英文版)》2016,(11)
By introducing the Dirac δ-function and Pauli exclusion principle in the presence of superstrong magnetic fields(SMFs), we investigate the influence of SMFs on beta decay and the change rates of electron fraction(CREF) of nuclides~(56)Fe,~(62)Ni,~(64)Ni and~(68)Ni in magnetars, which are powered by magnetic field energy. We find that the magnetic fields have a great influence on the beta decay rates, and the beta decay rates can decrease by more than six orders of magnitude in the presence of SMFs. The CREF also decreases by more than seven orders of magnitude in the presence of SMFs. 相似文献
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