2014年10月，彗星2013 A1 (Siding Spring) 会非常接近火星

谷歌译文：
2014年10月，彗星2013年A1（丁泉）会做一个非常接近火星美国航空航天局/喷气推进实验室近地天体计划办公室
3月5日2013年

10月19日2013年，2014年，彗星A1（赛丁泉）将通过非常接近火星，几乎可以肯定的星球，并可能更接近30万公里的范围内。我们目前的最佳估计它通过从火星表面约50000公里。这是火星最外层的卫星火卫二或不少于两次地球接近距离2012年DA14 2013年2月15日的2.5倍左右的距离。由于观察范围可定轨还比较短，目前的轨道是相当的不确定性，并作为额外的观测资料都包含在未来的轨道估计的名义接近的距离会改变。目前，火星位于可能的路径为彗星的范围内，我们不能排除这样的可能性，可能会影响火星的彗星。我们目前估计的影响概率是小于600，我们希望未来的观测将使我们能够完全排除了火星的影响。

登录/注册后可看大图

这台计算机图形描述了2013年的彗星A1（赛丁泉）通过内太阳系的轨道。图片来源：NASA / JPL-加州理工学院

虽然目前的日心轨道是双曲线（即，偏心率大于1），轨道是椭圆形的框架内太阳系的重心时表示。超过一百万年的旅程后，这颗彗星是来自我们的太阳系遥远的奥尔特云。它可以完成与短周期彗星的挥发性气体，往往缺乏由于他们经常返回到太阳的附近。

在接近火星的做法，彗星将可能实现零或亮从火星为基础的资产总视星等。所附的图显示了这颗彗星的近似，视大小和它的太阳能电池延伸角度，从火星作为时间的函数。由于彗星的视星等是如此的不确定，亮度曲线被切断的视星等零。然而，这颗彗星可能得到更明亮的零级以上，从火星。从地球，彗星将可能达到肉眼亮度，但它可以照亮视觉8级，从2014年9月中旬在南半球。

登录/注册后可看大图

这说明，准备由Jon Giorgini，显示了明显的总的视星等和太阳能电池延伸角度，从火星的中心

2013年1月3日在澳大利亚赛丁泉天文台罗布·麦克诺特彗星2013年发现了A1赛丁泉。前发现观测的档案位于延长观测时间回到2012年10月4日。
原文：

Comet 2013 A1 (Siding Spring) will make a very close approach to Mars in October 2014NASA/JPL Near-Earth Object Program Office
March 5, 2013

On Oct. 19, 2014, Comet 2013 A1 (Siding Spring) will pass extraordinarily close to Mars, almost certainly within 300,000 km of the planet and possibly much closer. Our current best estimate has it passing about 50,000 km from the surface of Mars. This is about 2.5 times the distance of Mars' outermost satellite Deimos or less than twice the Earth close approach distance of 2012 DA14 on February 15, 2013. Since the observation span available for orbit determination is still relatively short, the current orbit is quite uncertain and the nominal close approach distance will change as additional observations are included in future orbit estimates. Currently, Mars lies directly within the range of possible paths for the comet and we can't exclude the possibility that the comet might impact Mars. Our current estimate for the impact probability is less than one in six hundred and we expect that future observations will allow us to completely rule out a Mars impact.

登录/注册后可看大图

This computer graphic depicts the orbit of comet 2013 A1 (Siding Spring) through the inner solar system. Image credit: NASA/JPL-Caltech

Although the current heliocentric orbit is hyperbolic (i.e., eccentricity greater than one), the orbit is elliptic when expressed in the frame of the solar system's barycenter. After more than a million year journey, this comet is arriving from our solar system's distant Oort cloud. It could be complete with the volatile gases that short period comets often lack due to their frequent returns to the sun's neighborhood.

During the close Mars approach, the comet will likely achieve a total visual magnitude of zero or brighter as seen from Mars-based assets. The attached illustration shows the comet's approximate, apparent visual magnitude and its solar elongation angle as a function of time as seen from Mars. Because the comet's apparent magnitude is so uncertain, the brightness curve was cut off at apparent visual magnitude zero. However, the comet may get brighter than magnitude zero as seen from Mars. From Earth, the comet will not likely reach naked eye brightness but it could brighten to visual magnitude 8 as seen from the southern hemisphere in mid-September 2014.

登录/注册后可看大图

This illustration, prepared by Jon Giorgini, shows the apparent total visual magnitude and solar elongation angle as seen from the center of Mars

Rob McNaught discovered Comet 2013 A1 Siding Spring on January 3, 2013 at Siding Spring Observatory in Australia. Pre-discovery observations located in the archives have extended the observation interval back to Oct. 4, 2012.http://neo.jpl.nasa.gov/news/news179.html

靠。。。本来想让他俩撞上的说……{:soso_e149:}

捕获它！以后登彗旅游{:soso_e120:}