2012年主要流星雨

标签:
流星雨杂谈 |
分类: 天文天象资料 |
主要流星雨月相参考http://tianxiangyubao.happymm.cn/script/forum/view.asp?article_id=783476
1.Quadrantids (QUA)1月4日15时20分象限仪座流星雨极大(通常120颗,但有时可能会有60到200颗,不过今年受月光较强)
由IMCCE提供的流星体轨道数据图2012
Active: December 28 — January 12;
Maximum: January 4, 07h20m UT (λ⊙ =
283.16°); ZHR = 120 (can vary ∼ 60—200); Radiant: α = 230°, δ = +49°; Radiant drift: see Table 6; V∞ = 41 km/s; r = 2.1 at maximum, but variable; TFC: α = 242°, δ = +75° and α = 198°, δ = +40° (β > 40° N). IFC: before 0h local time α = 150°, δ = +70°; after 0h local time α = 180°, δ = +40° and α = 240°, δ = +70° (β > 40° N). |
http://www.imo.net/galleries/calendar/img/QUA.jpg
Waxing gibbous moonset for the predicted Quadrantid maximum leaves several dark-sky hours for visual observing before morning twilight begins from northern hemisphere sites this year. From many such places, the shower's radiant is circumpolar, in northern Boötes, first attaining a useful elevation after local midnight, improving steadily later, making this a reasonably favourable return. Observing sites from eastern North America east to the extreme west of Europe should be best-placed to record what happens, if the maximum time above is correct.
Modelling the stream is difficult. While the
graph shown in HMO p. 129, based on computations by Jérémie
Vaubaillon, seemed to suggest enhanced rates could happen between
roughly 01h to 10h UT on January 4, his recent results do not
support this. The λ⊙ = 283.16° maximum timing is based on the
best-observed return of the shower ever analysed, from IMO data
collected in 1992, as confirmed by radio results in most years
since 1996. The peak itself is normally short-lived, and can be
easily missed in just a few hours of poor northern-winter weather,
which may be why the ZHR level apparently fluctuates from year to
year. However, some genuine variability is probably present too. An
added level of complexity comes from the fact mass-sorting of
particles across the meteoroid stream may make fainter objects
(radio and telescopic meteors) reach maximum up to 14 hours before
the brighter (visual and photographic) ones, so observers should be
alert throughout the shower. A few years since 2000 seem to have
produced a, primarily radio, maximum following the main visual one
by some 9—12 hours. Visual confirmation of any repeat of such
behaviour would be welcomed. QUA activity tends to be very low more
than a day or so from the peak, and past observations have
suggested the radiant is diffuse away from the maximum too,
contracting notably during the peak itself, perhaps because of this
lower activity then. Imaging observations would be welcomed to help
investigate this topic, along with telescopic results.
2.Lyrids (LYR)4月22日13时30分天琴座流星雨极大(通常18颗,但有可能90颗,要看运气了)
Active: April 16—25; Maximum:
April 22, 05h30m UT (λ⊙ = 32.32°), but may vary — see text; ZHR = 18 (can be variable, up to 90); Radiant: α = 271°, δ = +34°; Radiant drift: see Table 6; V∞ = 49 km/s; r = 2.1; TFC: α = 262°, δ = +16° and α = 282°, δ = +19° (β > 10° S). |
http://www.imo.net/galleries/calendar/img/LYR.jpg
The λ⊙ = 32.32° timing given above is the 'ideal' maximum found in IMO results from 1988—2000. However, the maximum time was variable from year to year between λ⊙ = 32.0°—32.45° (equivalent to 2012 April 21, 21h30m to April 22, 08h30m UT). Activity was variable too. A peak at the ideal time produced the highest ZHRs, ∼ 23, while the further the peak happened from this, the lower the ZHRs were, down to ∼ 14. (The last very high maximum was in 1982, when a shortlived ZHR of 90 was recorded.) The mean peak ZHR was 18 over the thirteen years examined.
While generally thought of as having a short,
quite sharp, maximum, this investigation showed the shower's peak
length was inconstant. Using the Full-Width-Half-Maximum time (the
period ZHRs were above half the peak level), a variation between
14.8 to 61.7 hours was detected (mean 32.1 hours). The best rates
are normally achieved for just a few hours even so. The analysis
also confirmed that occasionally, as their highest rates occurred,
the Lyrids produced a brief increase in fainter meteors. Lyrids are
best viewed from the northern hemisphere, but are visible from many
sites north and south of the equator. As the radiant rises during
the night, watches can be carried out usefully after about
22h30m local time from mid-northern sites, but only
well after midnight from the mid-southern hemisphere. New Moon on
April 21 makes this year perfect for Lyrid maximum observing, and
if the ideal peak time recurs, it should be best-seen from sites
across much of North America, particularly the eastern half.
Remember, other maximum times are perfectly possible!
3.π-Puppids (PPU)船尾座π流星雨(今年极大值在4月23日18时30分,极大值流量在40颗左右每小时)
Active: April 15—28; Maximum:
April 23, 10h30m UT (λ⊙ = 33.5°); ZHR = periodic, up to around 40; Radiant: α = 110°, δ = –45°; Radiant drift: see Table 6; V∞ = 18 km/s; r = 2.0; TFC: α = 135°, δ = –55° and α = 105°, δ = –25° (β < 20° N). |
http://www.imo.net/galleries/calendar/img/PPU.jpg
Activity has only been detected from this source since 1972, with notable, short-lived, shower maxima of around 40 meteors per hour in 1977 and 1982, both years when its parent comet, 26P/Grigg-Skjellerup was at perihelion. Before 1982, little activity had been seen at other times, but in 1983, a ZHR of ∼ 13 was reported, perhaps suggesting material has begun to spread further along the comet's orbit, as theory predicts. Comet Grigg-Skjellerup's most recent perihelion in 2008 March produced nothing meteorically significant that April, but lunar circumstances in 2008 were poor, and faint-meteor activity (which was predicted as likely in advance) could have been missed. There were no predictions for activity in 2012 when this Calendar was prepared. The π–Puppids are best-seen from the southern hemisphere, with useful observations mainly practical there before midnight, as the radiant is very low to setting after 01h local time. April's new Moon creates perfect viewing circumstances this year.
Covering whatever happens is important, even if that is to report no obvious activity, as past datasets on the shower have typically been very patchy. So far, visual and radio data have been collected on the shower, but the slow, sometimes bright nature of the meteors makes them ideal subjects for imaging too. No telescopic or video data have been reported in any detail as yet.
4.June Boötids (JBO)6月27日11时六月牧夫座流星雨极大,变化0到100颗每小时之间,看运气
Active: June 22 — July 2;
Maximum: June 27, 03h UT (λ⊙ =
95.7°), but see text; ZHR = variable, 0—100+; Radiant: α = 224°, δ = +48°; Radiant drift: see Table 6; V∞ = 18 km/s; r = 2.2; TFC: α = 156°, δ = +64° and α = 289°, δ = +67° (β = 25°—60° N). |
http://www.imo.net/galleries/calendar/img/JBO.jpg
This source was reinstated on the Working List after its unexpected return of 1998, when ZHRs of 50—100+ were visible for more than half a day. Another outburst of similar length, but with ZHRs of ∼ 20—50 was observed on 2004 June 23, a date before definite activity had previously been recorded from this shower.
Consequently, the shower's start date was altered to try to ensure future activity so early is caught, and we encourage all observers to routinely monitor throughout the proposed activity period, in case of fresh outbursts. However, the 2010 return was disappointing. ZHRs of ∼ 20—50 were anticipated for June 23—24, but detected ZHRs then were less than 10, and not all experienced observers confirmed even these. Prior to 1998, only three more probable returns had been detected, in 1916, 1921 and 1927, and with no significant reports between 1928 and 1997, it seemed likely these meteoroids no longer encountered Earth. The dynamics of the stream were poorly understood, although recent theoretical modelling has improved our comprehension. The shower's parent, Comet 7P/Pons-Winnecke, has an orbit that now lies around 0.24 astronomical units outside the Earth's at its closest approach. Its most recent perihelion passage was in 2008 September. Clearly, the 1998 and 2004 returns resulted from material shed by the comet in the past which now lies on slightly different orbits to the comet itself. Dust trails laid down at various perihelion returns during the 19th century seem to have been responsible for the last two main outbursts. No predictions for activity are in-force for 2012, but conditions for checking are very favourable from the mid-northern latitudes where the radiant is best-seen (indeed it is usefully-observable almost all night from here), with only a waning crescent Moon on June 27. The prolonged — in some places continuous — twilight will cause difficulties, however. VID has suggested some June Boötids may be visible in most years around June 20—25, but with activity largely negligible except near λ⊙ = 92° (2012 June 23), radiating from an area about ten degrees south of the visual one found in 1998 and 2004, close to α α = 216°, δ = +38°.
5.Perseids (PER)英仙座流星雨(8月12日20时到22时30分最大100颗,月光较小)
Active: July 17 — August 24;
Maximum: August 12, 12h to
14h30m UT (λ⊙ = 140.0°—140.1°), but see text; ZHR =
100; Radiant: α = 48°, δ = +58°; Radiant drift: see Table 6; V∞ = 59 km/s; r = 2.2; TFC: α = 19°, δ = +38° and α = 348°, δ = +74° before 2h local time; α = 43°, δ = +38° and α = 73°, δ = +66° after 2h local time (β > 20° N); IFC: α = 300°, δ = +40°, α = 0°, δ = +20° or α = 240°, δ = +70° (β > 20° N). |
http://www.imo.net/galleries/calendar/img/PER.jpg
The Perseids produced strong activity from an unexpected primary maximum throughout the 1990s, associated with the perihelion passage of their parent comet, 109P/Swift-Tuttle, in 1992. The comet's orbital period is about 130 years. Further enhanced activity ahead of the usual maximum was last seen in 2004. Recent IMO observations (see HMO p. 145) found the timing of the mean or "traditional" broad maximum varied between λ⊙ ∼ 139.8° to 140.3°, equivalent to 2012 August 12, 07h to 19h30m UT. No additional peaks are anticipated this year, but this does not guarantee what will occur!
Although the Moon is a waning crescent, three
days after last quarter on August 12, it will rise from
mid-northern locations around local midnight to one a.m. Its
brightness and relative proximity to the Perseid radiant should be
considered more of a nuisance than a deterrent, even so. Such
mid-northern latitudes are the more favoured for Perseid observing,
as from here, the shower's radiant is usefully observable from
22h—23h local time onwards, gaining altitude throughout
the night. The near-nodal part of the "traditional" maximum
interval would be best-viewed from eastern Asia east to far western
North America (with increasing moonlight for places further east in
this zone), assuming it happens as expected. All forms of observing
can be carried out on the shower, though unfortunately, it cannot
be usefully observed from most of the southern hemisphere.
6.Draconids (DRA)(天龙座流星雨,今年也有可能爆发,极大在10月8日19时15分)
Active: October 6—10; Maximum:
October 8, 11h15m UT (λ⊙ = 195.4°), but see text; ZHR = periodic, up to storm levels; Radiant: α = 262°, δ = +54°; Radiant drift: negligible; V∞ = 20 km/s; r = 2.6; TFC: α = 290°, δ = +65° and α = 288°, δ = +39° (β > 30° N). |
http://www.imo.net/galleries/calendar/img/DRA.jpg
The Draconids are primarily a periodic shower
which produced spectacular, brief, meteor storms twice last
century, in 1933 and 1946, and lower rates in several other years
(ZHRs ∼ 20—500+). Most detected showers were in years when the
stream's parent comet, 21P/Giacobini-Zinner, returned to
perihelion, as it should next in 2012 February. Its orbital period
is currently about 6.6 years. The 2011 potentially strong return
was still to come when this text was written, but in 2005 October,
the comet's previous perihelion year, a largely unexpected outburst
happened near the nodal crossing time, around λ⊙ = 195.40°—195.44°,
probably due to material shed in 1946. Visual ZHRs were ∼ 35,
though radar detections suggested a much higher estimated rate,
closer to ∼ 150. Outlying maximum times from the recent past have
spanned from λ⊙ = 195.075° (in 1998; EZHRs ∼ 700), equivalent to
2012 October 8, 03h20m UT, through
the nodal passage time above, to λ⊙ = 195.63°—195.76° (a minor
outburst in 1999, not a perihelion-return year; ZHRs ∼ 10–20),
equating to 2012 October 8, 16h50m to
20h00m UT. No predictions of unusual activity are
in-force this October, but observers should be alert just in case.
Last quarter Moon on October 8 makes this quite a favourable year,
as the Moon rises in late evening for the many northern hemisphere
locations from where the Draconid radiant is circumpolar. The
radiant is at its highest during the first half of the night, and
Draconid meteors are exceptionally slow-moving.
7.Leonids (LEO)(狮子座流星雨极不稳定,今年极大值在17日17时30分极大只有15颗每小时,但有可能更大,如果你运气好,还可以看见真正的流星雨)
Active: November 6—30; Maximum:
November 17, 09h30m UT (nodal crossing at λ⊙ = 235.27°), but see below; ZHR = 15?; Radiant: α = 152°, δ = +22°; Radiant drift: see Table 6; V∞ = 71 km/s; r = 2.5; TFC: α = 140°, δ = +35° and α = 129°, δ = +6° (β > 35° N); or α = 156°, δ = −3° and α = 129°, δ = +6° (β < 35° N). IFC: α = 120°, δ = +40° before 0h local time (β > 40° N); α = 120°, δ = +20° before 4h local time and α = 160°, δ = 0° after 4h local time (β > 0° N); α = 120°, δ = +10° before 0h local time and α = 160°, δ = −10° (β < 0° N). |
http://www.imo.net/galleries/calendar/img/LEO.jpg
The most recent perihelion passage of the Leonids' parent comet, 55P/Tempel-Tuttle, in 1998 may be nearly 15 years ago now, but the shower's activity has continued to be fascinatingly variable from year to year recently. This year seems unlikely to produce enhanced rates, but there may be more than one peak. Apart from the nodal timing above, Mikhail Maslov has suggested that there could be a peak with ZHRs of ∼ 5—10 at 21h UT on November 17, followed by another increase to ZHRs of ∼ 10—15, probably of below-average brightness meteors, on November 20, at ∼ 06h UT (the latter due to the 1400 AD dust-trail).
ZHRs for the nodal peak are liable to be "normal", so probably about 15±5. November's waxing Moon is excellent news for either date, as it will set before or soon after the time the Leonid radiant first becomes usefully-observable, by local midnight or so north of the equator, afterwards for places further south. All observing methods can be employed. While these potential maximum timings do not exclude all others, if they prove correct, the two November 17 ones would be best-detectable from North American, and Middle East to Asian longitudes respectively, while that on November 20 would be similarly available from places between eastern North America east to extreme western North African longitudes.
8.α-Monocerotids (AMO)麒麟座α流星雨(11月21日17时55分极大,极大值一般到5颗,今年可能爆发到400颗每小时)
Active: November 15—25; Maximum:
November 21, 09h55m UT (λ⊙ = 239.32°); ZHR = variable, usually ∼ 5,
but may produce outbursts to ∼ 400+; Radiant: α = 117°, δ = +1°; Radiant drift: see Table 6; V∞ = 65 km/s; r = 2.4; TFC: α = 115°, δ = +23° and α = 129°, δ = +20° (β > 20° N); or α = 110°, δ = −27° and α = 98°, δ = +6° (β < 20° N). |
http://www.imo.net/galleries/calendar/img/AMO.jpg
The α–Monocerotids gave their most recent brief outburst in 1995 for Europe (the top EZHR, ∼ 420, lasted five minutes, the entire outburst 30 minutes). Recent modelling by Esko Lyytinen has indicated the main AMO trail will not cross the Earth's orbit again until 2017 and 2020. However, the Earth will not be near those points in November, so nothing is likely to happen then. A weak return may occur in November 2019, ahead of the 2020 encounter, depending on how broad the trail may be. The next strong AMO outburst is unlikely before 2043.
Despite this, observers should monitor the AMO
closely in every year possible, in case of unanticipated events.
The brevity of all past outbursts means breaks under clear skies
should be kept to a minimum near the predicted peak. The waxing
gibbous Moon causes few problems for the maximum date this year, as
the shower's radiant is well on view from either hemisphere after
about 23h local time, with moonset
around 00h—01h (later further north). If correct, the peak
timing would fall well for sites across North America.
9.Phoenicids (PHO)12月6日11时45分凤凰座流星雨极大,通常几乎没有,但是也有可能爆发到100,那就要看运气了
Active: November 28 — December 9;
Maximum: December 6, 03h45m UT (λ⊙ =
254.25°); ZHR = variable, usually none, but may reach 100; Radiant: α = 18°, δ = −53°; Radiant drift: see Table 6; V∞ = 18 km/s; r = 2.8; TFC: α = 040°, δ = −39° and α = 065°, δ = −62° (β < 10° N). |
http://www.imo.net/galleries/calendar/img/PHO.jpg
Only one impressive Phoenicid return has been
reported so far, that of its discovery in 1956, when the EZHR was
probably ∼ 100, possibly with several peaks spread over a few
hours. Three other potential, if uncertain, bursts of lower
activity have been claimed. Reliable IMO data has shown recent
activity to have been virtually nonexistent. This may be a periodic
shower however, and more observations of it are needed by all
methods. From the southern hemisphere (only), the Phoenicid radiant
culminates at dusk, remaining well on view for most of the night.
Last quarter Moon rises soon after midnight, leaving the first half
of the night with dark skies for observers on December 6. As the
predicted possible 2011 return was still to come when this was
written, any activity then may help refine the shower’s parameters
given here. No predictions of activity are in-force for 2012.
Phoenicids are extremely slow meteors.
10.Geminids (GEM)(双子座流星雨,每年最值得看的最稳定的流星雨,昨年受月光影响,今年将完全不会,理论期望值每半分钟1颗流星,今年最大值在12月14日7时30分,欧洲观测最佳,中国也不错哟!)
Active: December 4—17; Maximum:
December 13, 23h30m UT (λ⊙ = 262.2°); ZHR = 120; Radiant: α = 112°, δ = +33°; Radiant drift: see Table 6; V∞ = 35 km/s; r = 2.6; TFC: α = 87°, δ = +20° and α = 135°, δ = +49° before 23h local time, α = 87°, δ = +20° and α = 129°, δ = +20° after 23h local time (β > 40° N); α = 120°, δ = −3° and α = 84°, δ = +10° (β < 40° N). IFC: α = 150°, δ = +20° and α = 60°, δ = +40° (β > 20° N); α = 135°, δ = -5° and α = 80°, δ = 0° (β < 20° N). |
http://www.imo.net/galleries/calendar/img/GEM.jpg
One of the finest, and probably the most
reliable, of the major annual showers presently observable, whose
peak this year falls perfectly for new Moon. Well north of the
equator, the radiant rises about sunset, reaching a usable
elevation from the local evening hours onwards. In the southern
hemisphere, the radiant appears only around local midnight or so.
It culminates near 02h. Even from
more southerly sites, this is a splendid stream of often bright,
medium-speed meteors, a rewarding event for all observers, whatever
method they employ. The peak has shown slight signs of variability
in its rates and timing in recent years, with the more
reliably-reported maxima during the past two decades (HMO, p. 171)
all having occurred within λ⊙ = 261.5° to 262.4°, 2012 December 13,
07h to December 14,
04h UT. Near-peak rates usually
persist for almost a day, so much of the world has the chance to
enjoy something of the Geminids’ best. Some mass-sorting within the
stream means fainter telescopic meteors should be most abundant
almost a day ahead of the visual maximum, with telescopic results
indicating such meteors radiate from an elongated region, perhaps
with three sub-centres. Further results on this topic would be
useful.
11.Ursids (URS)(小熊座流星雨,每年最后出场的算比较大的流星雨,今年极大值在12月22日16时极大值只有10颗每小时,偶尔也可能会有50颗,又要靠运气行事了)
Active: December 17—26; Maximum:
December 22, 08h UT (λ⊙ = 270.7°),
but see below; ZHR = 10 (occasionally variable up to 50); Radiant: α = 217°, δ = +76°; Radiant drift: see Table 6; V∞ = 33 km/s; r = 3.0; TFC: α = 348°, δ = +75° and α = 131°, δ = +66° (β > 40° N); α = 063°, δ = +84° and α = 156°, δ = +64° (β 30° to 40° N). |
http://www.imo.net/galleries/calendar/2011/urs.png
A very poorly-observed northern hemisphere
shower, but one which has produced at least two major outbursts in
the past 70 years, in 1945 and 1986. Several lesser rate
enhancements have been reported as well, most recently from
2006–2008 inclusive which were probably influenced by the relative
proximity of the shower's parent comet, 8P/Tuttle, at perihelion in
January 2008. Other events could have been easily missed. Jérémie
Vaubaillon suggests there could be another peak this year, around
03h01m UT on December 22, with ZHRs of ∼ 15. The Ursid
radiant is circumpolar from most northern sites (thus fails to rise
for most southern ones), though it culminates after daybreak, and
is highest in the sky later in the night. The waxing gibbous Moon
at the maximum will set by roughly two a.m. from mid northern
sites, so this return is not unfavourable. The ∼ 03h timing would be best-seen from European
longitudes with no Moon, while the ∼ 08h peak would be good for eastern North America
similarly
更多流星雨2012
想要了解更多可以查由法国计算的流星雨体轨道图http://tianxiangyubao.happymm.cn/script/forum/view.asp?article_id=783435
以及爱尔兰阿马山天文台提供的数据图http://tianxiangyubao.happymm.cn/script/forum/view.asp?article_id=785737
有关2012年流星雨的更多信息:
4. 2012年南半球主要流星雨(由新西兰皇家天文学会提供)仅作参考
7. 2012年流星雨撮要(香港天文学会)
8. 2012年流星雨月相撮要 (香港天文学会)