n. (pl. -helia ) 【天、宇】(行星或彗星运行轨道最接近太阳的)近日点 (opp. aphelion); 最高点，极点。
Example Sentences:
1.
The anomalistic year is the time between successive transits of the earth through the perihelion . 近点年是地球连续两次通过近日点之间的时间。
2.
When perigee and perihelion coincide tidal range is at its greatest . 当月球与地球到达它们的近地点和近日点的时间恰好重合时，就会引起最大的潮汐。
3.
A comet is at perihelion when it is closest ( = very close ) to the sun 彗星最接近太阳时，它就是在近日点。
4.
Advance of the perihelion 近日点前移
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Advance of perihelion 近日点前移
6.
Comet giacobini - zinner passed the perihelion on 3 july this year , it is still relatively close to the earth in october . some astronomers predicted that draconids may be worth watching this year Giacobini - zinner彗星今年在7月3日通过近日点，至10月时与地球尚算接近，因此有天文学家认为今年可能会出现较可观的天座流星雨。
7.
Draconid meteor shower , associated with comet 21p giacobini - zinner , is not a major meteor showers throughout the year . it approaches the sun every 6 . 61years . if the earth is near the comet s perihelion during that period , a stronger meteor shower may occur 它的母体是21p giacobini - zinner彗星，每6 . 61年回归一次，若当时地球较接近彗星的近日点，便有可能出现较可观的流星雨。
8.
The numerical computation for the secular variable of the semi - major axis , solar distance at perihelion , orbital periods and longitude of perihelion has been made for fifteen meteor streams by using the solution of gylden - meshcherckii equations 利用g - m型变质量天体轨道根数变化方程的一阶和二阶解对15个流星群轨道半长轴、近日点距离、轨道周期和近日点经度因太阳质量损失造成的每世纪的长期改变效应做了数值计算，并得出计算结果。
9.
The most feature of the orbits of near - earth asteroids ( neas ) is that the semi - major axes of the orbits are nearly equal to that of the earth or the perihelia distances are approximate to or even less than the mean distance between the sun and the earth , thus they could move into inside of the earth ' s orbit , so that they might close approach or even colliside with the earth ( or other planets , such as the venus , the mars , etc . ) 近地小行星轨道的最大特点是其轨道半长径与地球轨道半长径相近，或近日距离接近甚至小于日地平均距离，其运动可深人到地球轨道的内部，这将导致该类小行星与地球（还有金星、火星等）十分靠近甚至发生碰撞。
10.
The asteroids are the most important small bodies in the solarsystem , and they mainly lies in the two locations - a main belt between the mars ' s orbit and the jupiter ' s and the near - earth space . the most feature of the orbits of near - earth asteroids ( neas ) is that the semi - major axes of the orbits are nearly equal to that of the earth or the perihelia distances are approximate to or even less than the mean distance between the sun and the earth , thus they could move into inside of the earth ' s orbit , so that they might close approach or even colliside with the earth ( or other planets , such as the venus , the mars , etc . ) . the characteristic brings about some difficulties in the numerical research during their orbital evolution , which leads to the failure of the normalization technique in the general removal impact singularities of celestial mechanics methods and the symplectic algorithm which is successfully applied to the investigation in quality . by comparing the computation effects of several common numerical methods ( including symplectic algorithm ) , and considering the nature of the movement of the small bodies , the corresponding treatments are provided here to improve the reliability of the computation 小行星是太阳系最重要的一类小天体，主要分布在两个区域；火星和木星轨道之间的一条主带和近地空间.近地小行星轨道的最大特点是其轨道半长径与地球轨道半长径相近，或近日距离接近甚至小于日地平均距离，其运动可深入到地球轨道的内部，这将导致该类小行星与地球(还有金星、火星等)十分靠近甚至发生碰撞.这一特征给其轨道演化数值研究带来一些困难，包括天体力学方法中一般消除碰撞奇点的正规化处理以及对定性研究十分成功的辛算法都将在不同程度上失效.通过对几种常用数值方法(包括辛算法)计算效果的比较，根据小天体运动自身的特性，给出了相应处理措施，从而可提高计算结果的可靠性
