SOHO探测器发现两颗新的短周期彗星

资料来自SOHO彗星主页http://uap-www.nrl.navy.mil/sungrazer


A new short period comet!
On September 18, Rainer Kracht (the famous SOHO comet hunter), found a small non-group object (SOHO-1532) in the LASCO C2 images. His initial reaction was that this object looked like it could be related to C/2004 X7 (SOHO), and his initial computations indicated it to be so. However, not stopping there, he pursued the idea that rather than being related to C/2004 X7, SOHO-1532 was in fact identical to it, implying an orbital period of approximately 3.8yrs. If true, this would mean that is should also have passed through the LASCO C2 camera in 2001. And sure enough, there was C/2001 D1 (SOHO), which was in the right place at the right time... but with completely the wrong orbital elements. However, such is the nature of the SOHO comet measurements, the observations recorded for many of these objects lead to highly ambiguous and uncertain orbital solutions. In the case of C/2001 D1, Rainer was able to identify a whole new set of images of the comet that were missed back in 2001. So armed with new observations, Dr Brian Marsden was able to officially confirm the link, and SOHO had it second short-period comet! (The  being about one year ago.)


Another new short period comet!
On September 24, while working on the previous comet (above), it occurred to Rainer that maybe there were other short-period comets in the SOHO archive that had just been overlooked due to the uncertain orbital solutions for the comets. Sure enough, it did not take him too long to find one! In his own words:

"The second trio needed a bit of luck and much patience. I had looked many times at the orbital elements of the non-group comets, but could not identify any possible pair (or trio).
After I had found the first trio, I looked again at my list of non-group comets and searched for low inclination, low q comets with short observational arcs. I found C/1999 X3, C/2004 E2 and C/2008 K10. The comparison of the apparent pathes looked terrible, but they were rather evently spaced indicating a orbital period of just over 4 years. The short observed arcs (0.11, 0.12, 0.16 days) meant that the orbits were not determined very well. So I continued the work.
I tried C/1999 X3 = C/2004 E2 with no success. I tried C/1999 X3 = C/2008 K10 with no success. I stopped the work on this trio.
I knew that I should also try C/2004 E2 = C/2008 K10. When I did this some hours later, all fell into one place."

Thus, Rainer was able to link the SOHO comets C/1999 X3, C/2004 E2 and C/2008 K10, finding SOHO's third confirmed short period comet, with a 4.22yr orbit around the Sun!

As a final point of interest about these short-period objects, there is a potential relation between them. Both of the above are in " 1:3 resonance orbits" with Jupiter, which makes them somewhat similar to a collective group of objects known as Alinda asteroids. However, the orbital eccentricity of the SOHO-discovered objects is really too high to make them Alindas, but it is theorized that with enough orbital evolution, their eccentricities could increase sufficiently to pass them close to (or into) the Sun.

So does that mean that these are asteroids and not comets? The problem there is in the definition of what exactly is an asteroid and a comet, and we have already seen that SOHO has already started to blur that line...

...能翻译一下么，很吃力啊

中国彗星与流星资讯网http://cmcn.y234.cn/也有相关报道

德国著名SOHO彗星猎手Rainer Kracht在2008年9月18日发现了一颗SOHO非族彗星，他意识到这可能是C/2004 X7 (SOHO)的回归，随后的计算表明它间隔3.8年回归一次，C/2001 D1(SOHO) 正好在预测的时间和位置上，随后不久Brian Marsden 教授确认了他的发现。这是一年以后发现的第2颗短周期彗星（第一颗由我国爱好者周波发现它的第三次回归）。

        9月24日,在进行以上工作的时候,Rainer Kracht意识到可能还有其他的彗星具有这样的情况,于是很快,他把C/1999 X3, C/2004 E2 和C/2008 K10联系到了一起,这是一颗具有4.22年的周期彗星。然而，随后的计算表明，它与Alinda 小行星具有相似的轨道，这使人想到它可能不是一颗彗星，而是一颗小行星（这将是SOHO探测器发现的第一颗小行星，呵呵）。

[ 本帖最后由 七月流火2 于 2008-10-3 13:00 编辑 ]

通过分析SOHO探测卫星拍摄的照片而发现的彗星一般称为SOHO彗星。
SOHO（Solar & Heliospheric Observatory）计划是由欧洲空间局（ESA）和美国宇航局（NASA）联合开展的合作项目，主要参与国有美、法、德、英等国。SOHO探测器上包括有LASCO(Large Angle and Spectrometric Coronagraph)、EIT(Extreme ultraviolet Imaging Telescope)、SWAN(Solar Wind Anisotropies)等12种主要观测设备，可以有效地对太阳本体、周边甚至是整个太阳系范围内的活动实施观测。自1995年12月投入运行以来，在太阳活动及太阳系空间环境等方面取得了不少成果。
由于SOHO所拍摄的图片是国际共享的，所以除了专业工作者外，天文爱好者们也可以及时获得并分析图片上的信息。1999年8月1日，澳大利亚的天文爱好者T.Lovejoy在SOHO图片网站LASCO系列图片中连续发现了SOHO-74、SOHO-75两颗彗星，开创了一个业余天文与互联网结合的崭新领域。从此，很多的天文爱好者不断加入到了SOHO彗星发现的行列，竞争也越来越激烈，竟然把专家们都纷纷挤出了发现擂台。（2000年专家只发现了少数几颗，2001年只发现了1颗，而业余爱好者每年都发现上百颗，显示了业余爱好者在这一领域的巨大热情和强劲实力！）。可以这样说，SOHO彗星的搜寻，是传统的目视寻彗和网络时代高科技技术高度结合的体现。

以上引自百度知道~

原来百度也有这方面的内容