09年imo年历之狮子座流星雨

Hall-Bopp

Leonids (LEO)
       
Active:         November 10-21
Maximum:         November 17 15h10m UT
        (nodal crossing at λo = 235°27) but see below
ZHR =         100+?
Radiant:         α = 152° δ = +22°
Radiant drift:         see Table 6
v∞ =         71 km/s; r = 2.9
TFC:         α = 140° δ = +35° and α = 129° δ = +06° (β > 35° N) or
        α = 156° δ = -03° and α = 129° δ = +06° (β < 35° N)
IFC:         α = 120° δ = +40° before 0h local time (β > 40° N);\p
        α = 120° δ = +20° before 4h local time and α = 160° δ = 00° after 4h (β > 0° N)
        α = 120° δ = +10° before 0h local time and α = 160° δ = -10° (β < 0° N)

The most recent perihelion passage of the Leonids' parent comet, 55P/Tempel-Tuttle, in 1998 may be more than a decade ago now, but the shower's activity has continued to be fascinatingly variable from year to year. This year may produce another enhanced return, with ZHRs predicted to peak at 100+ according to independent theoretical work by David Asher, Esko Lyytinen & Marku Nissinen, Mikhail Maslov, and Jérémie Vaubaillon. Trails laid down by the comet in 1466 and 1533 are expected to be the chief contributors to whatever happens, with peaks on November 17, due at sometime from about 20h40m to 22h UT then. Esko & Marku's work suggests the 1466 trail may produce heightened rates generally, with ZHRs above 20, from about 6h30m UT on November 17 till 0h30m UT on November 18, and likely above ~ 40 from ~ 16h-23h UT on November 17. This increased ZHR level will probably combine with that from the 1533 trail to push ZHRs up perhaps towards 120 at some stage between 21h-22h UT on the 17th. Mikhail suggested ZHRs should peak in that hour too, with ZHRs of ~ 130-140, but Jérémie's modelling implied the chance of a possible meteor storm, with ZHR peaks around 21h44m (ZHRs ~ 950+) and 21h51m UT (~ 600) combining to give a rate perhaps in the 1000-1500 range briefly. Other submaxima with lower rates are possible too, around November 17, 7h26m (ZHRs ~ 200+), 9h (~ 25-30), November 18, 0h04m (~ 15) and 19h UT (~ 10-15, faint meteors), according to some of these same researchers. The nodal crossing time listed above is another possible peak, based on previous non-enhanced returns, though its ZHR is likely to be a more modest 10-20.
Clearly, the evening to early morning UT hours of November 17/18 are likely to be of greatest observer interest. Luckily, new Moon on November 16 ensures perfectly dark skies for covering whatever events happen (remembering that there are no guarantees in meteor work!). As the Leonid radiant rises usefully only around local midnight (or indeed afterwards south of the equator), the 21h-22h UT apparently critical interval will fall best chiefly for sites across Asia, from the extreme east of Europe eastwards to Japan and places at similar longitudes, but with the possibility of some unusual activity at almost any stage from ~ 6h-24h UT on November 17, only European and African longitudes look set to miss out. Even here, radio coverage of the shower will be possible for part of that time. Of course, other possible maxima are not excluded (look out for updates nearer the time), and observers should be alert as often as conditions allow throughout the shower, in case something unexpected happens. All observing techniques can be usefully employed.
好久没发过帖子了

七月流火2

ZHR =         100+?
值得观测

bian

what's the meaning of ''15h10m UT''

恕我无知，谢谢！

bian

是极大持续的时间吗？

Hall-Bopp

是格林威治时间15点10分，也就是北京时间23点10分。像天津这里狮子座刚冒个头

阿球泡泡

是值得观赏。

meteorobs

感谢天津复兴中学高一年级组的英语李老师帮忙翻译:

狮子座流星群的母彗星“55P/Tempel-Tuttle”于1998年会比此后的10年达到最近一次近日点，但这次流星雨的活动已经每年都会有不同的变化。

今年可能会创造出另一个高点，ZHRs根据预测David Asher, Esko Lyytinen & Marku Nissinen, Mikhail Maslov, and Jérémie Vaubaillon的独立原理理论预测最大峰值会到达100+。

彗星轨迹的确定在1466和1533被认为是最大的贡献，在11月17日达到顶峰，从20h40m到 22h UT。Esko & Marku的成果中表明1466轨道可能提升速率，观测量在20以上

，从大约11月17日的6h30m UT到18日 0h30m UT 并很有肯能达到40以上在11月17日从16到23h UT。这个上升的平均值很大可能结合了1533轨道的数值（from the 1533 trail to push ZHRs up perhaps towards 120 at some stage between 21h-22h UT on the 17th).Mikhail表明观测量最高点在那个小时内也会达到顶点（130-140）。

Jérémie's modelling表明这次流星雨大最大峰值在21h44m和21h51mUT。

据研究另外一个降低的最大值也会在11月17日出现为7h26m (ZHRs ~ 200+), 9h (~ 25-30),在11月18日为0h04m (~ 15) and 19h UT (~ 10-15, faint meteors)。很明显，对观测爱好者来讲，17-18号

夜晚到清晨是最号的观测时间。幸运的是，16号的新月确保了天空的黑暗。在狮子座流星群辐射的有效增加仅仅在南方赤道附近。最佳观测点穿过亚洲，从欧洲的东部向东延伸到日本，

但在11月17日出现异常变化的话，欧洲和非洲可能会错过观测。当然，其他可能出现的数据不会被排除，观测者应该在观测的全程中随时警惕周围的情况，


以防其他没有意料到的情况发生。一切有利观测的仪器都是有必要装备的。

[ 本帖最后由 meteorobs 于 2008-9-30 23:04 编辑 ]