Instructions for authors

正Research in Astronomy and Astrophysics publishes original research papers and reviews on all branches of astronomy and astrophysics.Reviews are by invitation only.Important new results that require rapid publication can be submitted as a Letter(Letters must be restricted in length     

Relativistic transformation between y and TCG for Mars missions under IAU Resolutions

Considering the fact that the general theory of relativity has become an in- extricable part of deep space missions, we investigate the relativistic transformation between the proper time of an onboard clock τ and the Geocentric Coordinate Time （TCG） for Mars missions. By connecting τ with this local timescale associated with the Earth, we extend previous works which focus on the transformation between τ and the Barycentric Coordinate Time （TCB）. （TCB is the global coordinate time for the whole solar system.） For practical convenience, the relation between τ and TCG is recast to directly depend on quantities which can be read from ephemerides. We find that the difference between τ and TCG can reach the level of about 0.2 seconds in a year. To distinguish various sources in the transformation, we numerically calculate the contributions caused by the Sun, eight planets, three large asteroids and the space- craft. It is found that if the threshold of 1 microsecond is adopted, this transformation must include effects due to the Sun, Venus, the Moon, Mars, Jupiter, Saturn and the velocities of the spacecraft and Earth.     

The New Doppler Shift-and-Range Positioning Algorithm for the Global Navigation Satellite System

Under some circumstances in using the Global Navigation Satellite System （GNSS）, since navigation signals from the satellites are blocked a receiver cannot simultaneously track four or more satellites to estimate its 3-dimensional （3D） coordinates and clock bias. This paper proposes a Doppler Shift-and-Range （DS-R） positioning algorithm with which pseudoranges and Doppler shifts are simultaneously measured. The measurement results are used as inputs to four equations in the algorithm, and the 3D position can be estimated from the equations. Through this approach the algorithm can achieve real-time 3D positioning. By synthesizing multi-frequency observational results and adopting a new method of jointly using code-carrier phases, this algorithm expectably has accuracies similar to those of the standard approach of point positioning.     

星星为什么会眨眼？

“一闪一闪亮晶晶,满天都是小星星”是我们再熟悉不过的童谣了,夜晚仰望星空看繁星闪烁,有没有在脑海中飘过这个问题：小星星们为什么会一闪一闪“眨眼睛”呢？     

中国的时间文化

中国传统文化的一个核心内容是历法,《尚书尧典》中云:"历象日月星辰,敬授人时。"它是指用日、月、星等天文现象来描述、认识时间。在古代天文学中,中国传统天文主要做的就是历法,历经朝代更迭,共制定了102部历法。清朝最后颁行的历法名为《时宪历》,从字义上看就是以时为法,可见历法在中国传统社会中的重要。     

火星上的水来自何处

毫无疑问 ,火星上现在的温度非常低 ,气候无比干燥 ,大气很稀薄。而这种状态在星球表面起码保留了不少于数十亿年 ,但是否总是这样 ?地质学家在火星表层的结构中 ,看到了曾经存在过巨大的河流和湖泊的痕迹 ,并找到了河岸和整个大地被侵蚀的证据 ,但是气候学家没有发现水活动机制所需的温度。以TLSegura和KZahnle为首的科罗拉多州立大学和埃孟斯研究中心的工作人员提出了自己的观点。他们认为 ,巨大陨石的降落导致大量地下冰的融化并引起了短时的洪水 ,并留下了今日所看到的痕迹。作者提出了存在着由于天体降落而产生的 2 5个巨大陨石坑的…     

《天文研究与技术》征稿简章

1.《天文研究与技术》是中国科学院国家天文台主办的学术性刊物。本刊主要登载天文学及相关学科的观测研究、实测技术和方法、专题述评等方面的学术论文以及有关天文新发现的研究快讯。欢迎广大天文和相关学科的科技工作者投稿。     

高能中微子和极高能宇宙线起源天体的理论研究

极高能宇宙线一般指来自地外的能量高于1018电子伏特(eV)的高能质子与原子核,其起源的研究一直是高能天体物理和粒子天体物理领域的热点问题.近年随着一些大型探测器(如Pierre Auger天文台)的运行,极高能宇宙线的研究取得很大进展.然而由于极高能宇宙线事例相对较少及其在从源到地球传播过程中的复杂性(如与宇宙微波背景辐射以及磁场的作用),需要通过观测这些宇宙线在强子反应中产生的次级粒子(如中微子)来获得其起源的额外信息.最近,位于南极的IceCube中微子天文台探测到了54个能量分布在60TeV{3PeV内的中微子事例,开启了高能中微子天文学的新时代.在本文中,我们研究了高能中微子、极高能宇宙线的天体物理起源以及它们之间可能的联系.