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ＰＯ９７型ＧＰＳ／Ｂ码解调器把ＧＰＳ技术融入Ｂ码设备中,用于自动定时定位和精密时间同步。该设备的ＧＰＳ时码接口解出ＧＰＳ时间信号,并同步所有的时标信号和时间码信号。主要介绍了该接口的硬件和软件的实现过程。 相似文献
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基于对9颗类太阳色球活动恒星高信噪比的高色散光谱观测, 测量了这些恒星锂线(入 = 6707.8 A'')的等值宽度, 计算了这些恒星表层锂元素丰度. 通过研究这些类太阳色球活动恒星锂丰度和X射线光度之间的关系, 发现X射线光度 强的类太阳色球活动恒星锂丰度值大于X射线较弱的恒星. 也就是说活动性较强的类太阳色球活动恒星其锂丰度较高, 活动性较弱的类太阳色球活动恒星其锂丰度较低. 考虑到主序的类太阳恒星锂元素和恒星自转速度随着恒星年龄的增加逐渐减少, 以及随着类太阳色球活动恒星自转速度的减小, 色球活动又逐渐变弱. 因此类似于锂丰度, 类太阳色球活动恒星自转速度的大小和恒星的 活动水平也同样可以表明恒星的年龄. 相似文献
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太阳的视运动和时间系统(一) 总被引：1，自引：0，他引：1
上一次,我们讲到恒星的时角随时间均匀增大,地球每自转一周,时角就会变化24h,所以说测量恒星的时角变化可以作为计量时间的一种方式。恒星的时角每增加24h的时间为一个恒星日;恒星日又可划分为恒星小时,恒星分和恒星秒等。恒星时大小上等于春分点的时角。然而恒星时和恒星日并不是我们日常所使用的时间单位。 相似文献
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恒星形成于分子云环境中。近30多年的观测研究使得天文学家对小质量恒星的形成有了相对明确的认识：小质量恒星通过坍缩、吸积和外向流的路标而形成。至于大质量恒星，其形成过程还存在着许多不确定因素，现有的观测证据表明：大质量恒星也可能通过坍缩、吸积和外向流的路标来形成，但也不排除在星团中通过中小质量恒星聚合而成的因素。大质量恒星形成与致密电离氢区(UCHII)成协较好，而与大质量恒星形成区成协的分子云环境中，既有大质量恒星也有小质量恒星形成。综述了恒星形成各个阶段的观测结果和研究现状以及成协的天体物理环境情况。未来的观测和研究重点在于，大质量恒星形成以及星团环境中的恒星形成。 相似文献
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恒星尘埃的实验室研究--实验天体物理学 总被引：1，自引：0，他引：1
原始球粒陨石含有来自恒星的微小固体颗粒(微米级),这些尘埃的同位素组成与太阳系物质截然不同,它们是目前唯一能直接获得的恒星固体样品．已发现的恒星尘埃有金刚石、石墨、碳化硅、刚玉、尖晶石、氮化物、和硅酸盐等,它们的母体恒星包括红巨星,AGB恒星、新星和超新星．对恒星尘埃的研究,使得更深入地了解星系的化学演化历史、恒星内部的核反应和湍流机制、恒星大气中尘埃的形成、星际介质物理现象等．恒星尘埃把天体物理领域延伸到了微观世界,它有机地结合了地球化学实验技术和天体物理理论,开辟了一门崭新的天文学分支实验天体物理学． 相似文献
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第一代恒星（星族Ⅲ恒星）标志着宇宙从暗物质时代到现在已知的宇宙的转折点。目前对第一代恒星（星族Ⅲ恒星）的观测结果表明，在银河系中还没有发现零金属丰度的恒星，金属丰度[Fe/H]≤-2.5的恒星极少。由于近几年的BPS巡天，银河系中已知的极端贫金属丰度的恒星数目大大增多。目前，可探测到的极端贫金属星的金属丰度[Fe/H]最低约为－4．1。金属丰度在－4到－3之间的恒星大约有100多颗，这些恒星的运动学特性非常类似于其它晕星。然而还没有发现第一代恒星，或金属丰度[Fe/H]≤-5的恒星。关于第一代恒星的形成过程、初始质量函数以及存在于银河系的什么地方，都还没有任何直接的证据。但第一代恒星确实存在。第一代恒星这个谜一般的实体，向观测和理论天文学家提出了巨大挑战。为探测和预言银河系中的第一代恒星，天文学家提出了许多观测方案和理论模型。对有关第一代恒星在观测和理论研究上的进展进行了综述。 相似文献
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本文根据球状星团所特有的金属丰度特征,利用星族综合方法,探讨了球状星团诸恒星的形成史。研究表明,这些恒星不可能通过恒星形成率和初始质量函数均不随时间变化的单一恒星形成模式产生。原初云通过恒星演化而得到金属丰度污染的过程和多数恒星的形成过程必须分为两个不同的阶段。 球状星团得到金属丰度污染的过程中,若恒星形成具有通常的初始质量函数,则其恒星形成率必须较低,且初始质量函数不能太陡,从而使污染过程中只形成数量较少的低质量恒星,以保证单个球状星团内金属丰度的均匀性。另一种可能性是污染阶段有非常特殊的初始质量函数,只形成大质量的恒星,从而除提供适量污染外不留下任何痕迹。 多数恒星应是在原初云不同部位得到适当污染后通过局域的短暂的爆发性恒星形成(星暴过程)产生。本文进一步探讨了在Fan和Rees球状星团形成模型的框架下,两相介质中温云块相互碰撞造成星暴过程的可能性。 相似文献
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Using the cosmic ray sidereal and anti-sidereal diurnal variations observed underground in London and Hobart during the period 1958–1983, it is demonstrated that: (1) the phase changes of the apparent sidereal diurnal variation observed only in the Northern Hemisphere cannot be attributed to the change of the heliomagnetospheric modulation of galactic cosmic ray anisotropy caused by the polarity reversal of the solar magnetic field, but that they are due to the fluctuation of the spurious sidereal variation produced from the anisotropy responsible for the solar semi-diurnal variation; (2) the spurious sidereal variation can be eliminated from the apparent variation by using the observed anti-sidereal diurnal variation; and (3) after the elimination, the sidereal diurnal variations in the Northern and Southern Hemispheres almost coincide with each other and are stationary throughout the period, regardless of the polarity reversal of the heliomagnetosphere. The origin of the corrected sidereal variation is discussed. 相似文献
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A. Kubičela 《Solar physics》1986,106(2):403-410
Kinematic picture concerning the solar synodic and sidereal rotation axes has been considered in some detail. Large changes in the synodic angular rotation velocity and the position of the synodic rotation pole have been found for some hypothetical cases of out-of-ecliptic intra-Mercurian orbits. The influence of solar differential rotation and variable planetary velocity along the orbit have been taken into account and a continuous set of co-existing synodic poles oscillating around a mean position has been found. The relevant numerical values for the Earth are given and the possibility of detecting the existence of the two rotation axes has been pointed out. 相似文献
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Adding the angular velocity of sidereal solar rotation and the apparent rotational effect of the Earth's revolution vectorially, a new synodic solar rotation vector has been obtained. The sidereal and synodic solar rotation axes (and equators) are separated. Using the known parameters of the Earth's orbital motion, the synodic rotation angular velocity and the inclination of the synodic equator, the corresponding sidereal rotation parameters have been calculated (ω1 = 2.915 × 10#X2212;6 rad s#X2212;1 and i 1 = 6.076). Various linear rotational velocities at the solar globe are briefly described. 相似文献
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We have analyzed the sidereal diurnal variation of cosmic rays, using 620 station-years of neutron monitor data during the period 1958–1979. The sidereal variation averaged over the period for all the stations in the Northern Hemisphere is different from the corresponding variation in the Southern Hemisphere. The difference is statistically significant and can be identified with the spurious sidereal variation produced from the stationary anisotropy of solar origin, responsible for the solar semi-diurnal variation. The variation common to both hemispheres is also exceptionally significant from the statistical point of view and could be regarded as being due to a uni-directional galactic anisotropy. This variation has an amplitude of 0.0204 ± 0.0015% and a phase of 6.8 ± 0.3 h and is clearly different from that ( ～ 0.05%, 0 ～ 3 h) observed in the high rigidity region (500 ～ 104 GV). The physical meaning of the variation is discussed from the standpoint of the heliomagnetospheric modulation of galactic anisotropy. 相似文献
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It is demonstrated that, at high rigidities (50 GV and beyond), all the main features of cosmic-ray anisotropy of solar origin
can be explained in terms of regular particle motion —without diffusion being involved — in the large-scale interplanetary
magnetic field (IMF). A simple model of the IMF is adopted with a corotating warped neutral sheet separating the regions of
alternative polarities; the warped shape is indispensable for obtaining any form of anisotropy. Energy losses occurring along
various computed trajectories are calculated to give the sidereal, solar and antisidereal intensity waves. The reliability
of the variations obtained are checked by changing the parameters of the IMF model. Both the sense and amplitude of the polarity-dependent
sidereal vector are compatible with those established experimentally. Also reproduced are the predictions of corotation in
addition to the 3-hour phase of the semi-diurnal wave. The corotation is found to be near perfect at 50 GV, while it reduces
at 100 GV. The model presented accounts for the change of solar daily vector that was observed in 1969. 相似文献
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The sidereal period of Ceres is refined from 9.075 h to 9.074170±0.000002, making use of recent and historical lightcurves spanning almost 50 years. An observed increase in the amplitude of the lightcurve with solar phase angle is consistent with bright, discrete albedo features contributing a greater fraction of light as the defect of illumination increases. Observations near the same phase angle over this time span show no evidence of changes that would indicate active surface processes. 相似文献
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Data from underground muon telescopes in New Mexico and Bolivia are analyzed in sidereal time and anti-sidereal time to study anisotropies in the rigidity range 20 GV to a few 100s of GV. Using both vertical and North- and South-pointing telescopes in both hemispheres, a latitude range of 70°N–50°S is covered. The distribution of cosmic rays in the inner heliosphere gives rise to a diurnal variation in anti-sidereal time, and also produces a spurious contribution to the anisotropy in sidereal time. It is shown that the anti-sidereal variation is of the P21 type, having opposite phase in the Northern and Southern Hemispheres, and maximum amplitude at mid latitudes. The anti-sidereal data are used to correct the sidereal data, using the Nagashima method (Nagashima, Sakakibara, Fenton and Humble, 1985); the resulting corrected sidereal vectors for Northern Hemisphere telescopes have their sidereal maxima close to 3 h sidereal time, in reasonable agreement with sidereal data at higher energies from small air showers. The Nagashima correction also appears to eliminate effects due to the reversal of the Sun's polar magnetic field which show up in the unconnected sidereal data, and which also remain in corrected data using an alternative correction. 相似文献
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This article presents a comparative analysis of solar activity data, Mt Wilson diameter data, Super-Kamiokande solar neutrino data, and nuclear decay data acquired at the Lomonosov Moscow State University (LMSU). We propose that salient periodicities in all of these datasets may be attributed to r-mode oscillations. Periodicities in the solar activity data and in Super-Kamiokande solar neutrino data may be attributed to r-mode oscillations in the known tachocline, with normalized radius in the range 0.66–0.74, where the sidereal rotation rate is in the range 13.7–14.6 year−1. We propose that periodicities in the Mt Wilson and LMSU data may be attributed to similar r-mode oscillations where the sidereal rotation rate is approximately 12.0 year−1, which we attribute to a hypothetical “inner” tachocline separating a slowly rotating core from the radiative zone. We also discuss the possible role of the Resonant Spin Flavor Precession (RSFP) process, which leads to estimates of the neutrino magnetic moment and of the magnetic field strength in or near the solar core. 相似文献
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V. A. Kotov 《Solar physics》2017,292(6):76
Regular measurements of the general magnetic field of the Sun, performed over about half a century at the Crimean Astrophysical Observatory, the J. Wilcox Solar Observatory, and five other observatories, are considered in detail for the time 1968?–?2016. They include more than twenty-six thousand daily values of the mean line-of-sight field strength of the visible solar hemisphere. On the basis of these values, the equatorial rotation period of the Sun is found to be 26.926(9) d (synodic). It is shown that its half-value coincides within error limits with both the main period of the magnetic four-sector structure, 13.4577(25) d, and the best-commensurate period of the slow motions of the major solar system bodies, 13.479(22) d (sidereal). The probability that the two periods coincide by chance is estimated to be about \(10^{-7}\). The true origin of this odd resonance is unknown. 相似文献
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In the previous paper (Nagashima et al., 1982), we have reported the yearly averaged modulation of galactic cosmic ray anisotropy in the heliomagnetosphere. In the present paper, we analyze the seasonal (annual) dependence of the modulation, using the frequency modulation method. The seasonal variation of the sidereal daily variation produced from the anisotropy is resolved into variations with proper sideband frequencies, such as solar and anti-sidereal variations. These side-band variations are predominant in the rigidity region of 102 ～' 103 GV and show the following characteristics.(1) Being similar to the average sidereal variation, they are strongly dependent on the polarity state (‘positive’ or ‘negative’) of the heliomagnetosphere.(2) The side-band variations with frequencies lower than the sidereal frequency (366 cycle/year) generally predominate over those with higher frequencies. The most predominant variations are produced from the component of the uni-directional anisotropy projected to the Earth's rotation axis and could be observed as the solar and anti-sidereal diurnal variations.(3) If the flat neutral sheet of the heliomagnetosphere is replaced with the wavy neutral sheet, side-band variations in the positive state tend to diminish with the increase of the heliolatitudinal extent of the wavy neutral sheet, while those in the negative state almost retain their magnitude.(4) These variations depend also on the observation periods when the Earth is located either in the “toward” field or in the “away” field. This T-A dependence changes with the transition from the positive state to the negative and increases with the increase of the heliolatitudinal extent of the wavy neutral sheet. The most remarkable T-A dependence is observed in solar diurnal variation arising from the component of the unidirectional anisotropy projected to the Earth's rotation axis and can be used for the determination of the direction of the anisotropy. 相似文献