C/2013 A1撞击火星概率分析

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Comet C/2013 A1 (Siding Spring) – a possible collision with Mars
February 25th, 2013 |  Author: Leonid Elenin
L. EleninThere is a chance that the comet C/2013 A1 (Siding Spring), discovered
in the beginning of 2013, might collide with Mars. At the moment, based on the
observation arc of 74 days, the nominal close approach distance between the red
planet and the comet might be as little as 0.00073 AU, that is approximately
109,200 km! Distance to Mars’ natural satellite Deimos will be smaller by 6000
km, making it 103,000 km. On the 19th October 2014, the comet might reach
apparent magnitude of -8…-8.5, as seen from Mars! Perhaps it will be possible to
accuire high-resolution images from the Mars Reconnaissance Orbiter (MRO).
Since C/2013 A1 is a hyperbolic comet and moves in a retrograde orbit, its
velocity with respect to the planet will be very high, approximately 56 km/s.
With the current estimate of the absolute magnitude of the nucleus M2 = 10.3,
which might indicate the diameter up to 50 km, the energy of impact might reach
the equivalent of staggering 2×10¹º megatonnes! This kind of event can leave a
crater 500 km across and 2 km deep. Such an event would overshadow even the
famous bombardment of Jupiter by the disintegrated comet Shoemaker–Levy 9 in
July 1994, which by some estimates was originally 15 km in diameter.
All that is said above is based on the current measurements, and will of course
be refined as more data comes in. In any case, even now we can say that the
close approach will happen. The current orbit uncertainty allows for a collision
scenario, but the possibility of this is small. Astronomers keep watching this
interesting comet, and I will keep you up to date with the news.
Nominal orbital elements were taken from JPL NASA website, calculations were
done in Mercury package.
Translated by Maksim Kakitsev.

2013年发现的第一颗彗星就瞄着火星去了……火星上真有智慧生命的话，一定会有所行动~~要没有动静就说明以前就没有，或者刚刚没有……，也可能刚有，就变没有了……{:soso_e120:}

曾潇 发表于 2013-2-27 13:01

                               
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2013年发现的第一颗彗星就瞄着火星去了……火星上真有智慧生命的话，一定会有所行动~~要没有动静就说明以前 ...

也可以本来没有，彗星一去就有了

火星人會移民地球嗎?

如果撞击兴许是好事。 {:soso_e100:}

如果真的撞上了，对火星车有影响不？火星车也许能拍到世界末日的照片了

vwuvwu 发表于 2013-2-27 13:33

                               
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也可以本来没有，彗星一去就有了

能扛得住相撞时的温度的东西估计活在太阳上吧

曾潇 发表于 2013-2-27 15:52

                               
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能扛得住相撞时的温度的东西估计活在太阳上吧

坠落地球的陨石中就发现过氨基酸，是能组成生物体蛋白质的，同样的事情发生在火星或许会有机会发展出生命，如果那个彗星有的话。

期待

10万公里估计撞不上，火星的小行星撞击率要比地球低50倍以上。

转：

@Pachacoti-交阯越人
結合來自Kitt Peak新的觀測數據，Aldo Vitagliano計算發現C/2013 A1撞擊火星概率進一步上升，達約0.3%！！

Close approach to Mars. Up-to-date analysis
March 2nd, 2013 |  Author: Leonid Elenin
After adding the recent measurements, taken by Tomas Vorobjov at Kitt Peak Observatory (March 1, 2013), the distance of closest approach increased to 0.00047 AU (70 500 km). CA time is October 19, 2014, 19:09:24.48 UT. I think what we can fairly accurately estimate these parameters, before the temporary pause in the observations of this comet, due to it’s low elongation. Thanks to Tomas!

If anyone have recent measurements of this comet, I will appreciate if you will send it to me. TIA!

转：
小龙哈勃: 重要更新：MPC两个小时前公布了泛星项目早至发现前2个月的数据，JPL在几分钟前火速更新了轨道根数。最小距离仍然是显眼的0，而中值比起之前减小了一半，只有5万公里了。简单的估计表明撞击概率仍然维持在千分之一这个量级，我回头也玩玩蒙特卡洛试试。