http://www.asyura2.com/11/jisin17/msg/545.html
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元々、氷と塵の塊で、小さくて軽いものだから、10回くらい太陽に接近すれば分解、消滅するのだが、Eleninは早くも今回の接近で壊れたらしい。
破片が地球に衝突する可能性も、ほとんど無さそうだ
http://ameblo.jp/xrekix/
エリニン彗星 消滅？
2011年9月11日 ＜エレニン彗星が太陽に最接近する日＞
2011年9月26日〜３０日 ＜3点が一直線に並ぶ日＞
2011年10月17日〜２０日＜エレニン彗星が地球に最接近する日＞
2011年11月23日〜２６日＜3点が一直線に並ぶ日＞
2012年12月28日〜３１日＜3点が一直線に並ぶ日＞
2014年1月2日 ＜3点が一直線に並ぶ日＞
ーーーーーーーーーーーーーーーーーーーーーーーーーーーー
2010年２月２７日 - 3点が一直線に並んだ日~6.042AU ? チリEQ, 8.8
2010 年９月４日- 3点が一直線に並んだ日~6.258AU ? ニュージーランド EQ, 7.1
2011 年３月１１日- 3点が一直線に並んだ日~2.155AU ? 日本EQ/Tsunami, 9.0
http://www.asyura2.com/11/jisin17/msg/476.html#c56
Comet Elenin Self-Destructs
Whenever astronomers discover a comet headed inbound toward a close encounter the Sun, there's always buzz among observers about how bright it might get. That was certainly the case last December, when Comet Elenin (C/2010 X1) made its debut. Many hoped it would become easily visible to the unaided eye as it rounded perihelion nine months later.
By April, that initial enthusiasm had waned a bit, as it became clear that Comet Elenin was small and intrinsically faint.
The keys to its peak visibility were the closeness it would eventually have to the Sun on September 10th (0.48 astronomical unit, about 45 million miles) and to Earth in mid-October (0.23 a.u.). In fact, amateur observations through July and early August suggested that this interloper might even be ahead of schedule, brightness-wise. The hearts of comet observers everywhere raced a little faster.
Comet Elenin in decline
Here's how Comet Elenin (C/2010 X1) looked on the evening of August 27, 2011. Observing from Chatelaine in southeast Australia, Michael Mattiazzo combined 15 10-second exposures taken through an 11-inch telescope. The edge-on 13th-magnitude galaxy NGC 4348 is at lower right.
Michael Mattiazzo
Now all bets are off. Within the past week the comet's brightness has declined by 50%, dropping a half magnitude between August 19th and 20th, according to Australian observer Michael Mattiazzo. (The comet's current location in western Virgo makes it virtually unobservable from northern latitudes.)
Worse, images show Comet Elenin's bright core becoming elongated and diffuse ― the telltale signs that its icy nucleus has either broken in two or disintegrated altogether.
One veteran comet-watcher who's not surprised is John Bortle. Four months ago, based on Elenin's performance to that point, he cautioned, "The comet may be intrinsically a bit too faint to even survive perihelion passage." And his words have proved prescient, as the fading continues (estimates are near 9th magnitude) and there's speculation that this object or its remnants might not be around much longer.
I guess all those pseudoscientific bloggers who predicted planet-altering encounters with a cosmic visitor bright enough to be seen in broad daylight will just have to find something else to worry about.
Posted by Kelly Beatty, August 30, 2011
related content: Celestial events
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