Search for New Parent Bodies of Meteoroid Streams Among Comets. I. Showers of Comets 126P/1996 P1 and 161P/2004 V2 with Radiants on Southern Sky

We deal with theoretical meteoroid streams the parent bodies of which are two Halley-type comets in orbits situated at a relatively large distance from the orbit of Earth: 126P/1996 P1 and 161P/2004 V2. For two perihelion passages of each comet in the far past, we model the theoretical stream and follow its dynamical evolution until the present. We predict the characteristics of potential meteor showers according to the dynamical properties of theoretical particles currently approaching the orbit of the Earth. Our dynamical study reveals that the comet 161P/2004 V2 could have an associated Earth-observable meteor shower, although no significant number of theoretical particles are identified with real, photographic, video, or radar meteors. However, the mean radiant of the shower is predicted on the southern sky (its declination is about −23°) where a relatively low number of real meteors has been detected and, therefore, recorded in the databases used. The shower of 161P has a compact radiant area and a relatively large geocentric velocity of ∼53 km s⁻¹. A significant fraction of particles assumed to be released from comet 126P also cross the Earth’s orbit and, eventually, could be observed as meteors. However, their radiant area is largely dispersed (declination of radiants spans from about +60° to the south pole) and, therefore, mixed with the sporadic meteor background. An identification with real meteors is practically impossible.     

Venus-intercepting meteoroid streams

This study is motivated by the possibility of determining the large-body meteoroid flux at the orbit of Venus. Towards this end, we attempt to estimate the times at which enhanced meteoric activity might be observed in the planet's atmosphere. While a number of meteoroid streams are identified as satisfying common Earth and Venus intercept conditions, it is not clear from the Earth-observed data if these streams contain large-body meteoroids. A subset of the Taurid Complex objects may produce fireball-rich meteor showers on Venus. A total of 11 short-period, periodic comets and 46 near-Earth asteroids approach the orbit of Venus to within 0.1 au, and these objects may have associated meteoroid streams. Comets 27P/Crommelin and 7P/Pons–Winnecke are identified as candidate parents to possible periodic meteor showers at the orbit of Venus.     

The P/Halley Stream: Meteor Showers on Earth, Venus and Mars

We have simulated the formation and evolution of comet 1P/Halley’s meteoroid stream by ejecting particles from the nucleus 5000 years ago and propagating them forward to the present. Our aim is to determine the existence and characteristics of associated meteor showers at Mars and Venus and compare them with 1P/Halley’s two known showers at the Earth. We find that one shower should be present at Venus and two at Mars. The number of meteors in those atmospheres would, in general, be less than that at the Earth. The descending node branch of the Halley stream at Mars exhibits a clumpy structure. We identified at least one of these clumps as particles trapped in the 7:1 mean motion resonance with Jupiter, potentially capable of producing meteor ourbursts of ZHR∼1000 roughly once per century.     

Earth-orbit-approaching comets and their theoretical meteor radiants

Sixteen comets produce recognizable meteor showers that are found in A. F. Cook's (1973, In Evolutionary and Physical Properties of Meteoroids (C. L. Hemenway, P. M. Millman, and A. F. Cook, Eds.), pp. 183–191, U.S. Govt. Printing Office, Washington, D.C.), working list of meteor streams. Of these, five are long period, including one in a parabolic and one in a hyperbolic orbit. The largest Earth-comet orbit miss distance is 0.20 AU for P/Encke and the Northern and Southern Taurids. Using this is an upper limit for meteor showers from comets, all comets which approach the Earth's orbit to within 0.20 AU were extracted from the Catalogue of Cometary Orbits (B. G. Marsden, 1979. 3rd ed., Central Bureau of Astronomical Telegrams, IAU SAO, Cambridge, Mass.). A compilation of such comets is presented by date minimum approach, along with the distance of closest approach and the theoretical geocentric radiants and velocities of possible associated meteor showers. Both pre- and postpperihelion encounters with the Earth's orbit are considered. There are 240 entries for 178 long-period comets, and 36 for 28 short-period comets. It is noted that all short-period comets that have approached the Earth's orbit to within 0.08 AU have produced meteors, except P/Lexell, P/Finlay, P/Denning-Fujikawa, and P/Grigg-Skjellerup. Attention is called to the favorable observing conditions for detecting meteors from P/Grigg-Skjellerup in April 1982, and for the possibility of another great Draconid storm from P/Giacobini-Zinner in October 1985. A comparison is made between observed sporadic meteor rates and the distribution of theoretical radiants throughout the year, from which it is concluded that the currently known comets can account for sporadic meteors. A criterion is developed to test whether or not an observed meteor shower can be associated with a given theoretical radiant. Based on known examples, a qualitative model for comet/meteor relationships is also presented.     

Meteor Showers Associated with the Taurid Complex Asteroids

Recent theoretical and observational work has shown that the asteroids belonging to the Taurid meteoroid complex have a cometary nature. If so, then they might possess related meteoroid streams producing meteor showers in the Earth atmosphere. We studied the orbital evolution of ten numbered Taurid complex asteroids by the Halphen-Goryachev method. It turned out that all of these asteroids are quadruple crossers relative to the Earth's orbit. Therefore their proposed meteoroid streams may in theory each produce four meteor showers. The theoretical orbital elements and geocentric radiants of these showers are determined and compared with the available observational data. The existence of the predicted forty meteor showers of the ten Taurid complex asteroids is confirmed by a search of the published catalogues of observed meteor shower radiants and orbits, and of the archives of the IAU Meteor Data Center (Lund). The existence of meteor showers associated with the Taurid Complex Asteroids confirms that, most likely, these asteroids are extinct comets. This revised version was published online in July 2006 with corrections to the Cover Date.     

PREDICTING MARTIAN AND VENUSIAN METEOR SHOWER ACTIVITY

Based on the number of planet-approaching cometary orbits at Mars and Venus relative to the Earth, there should be ample opportunities for observing meteor activity at those two planets. The ratio of planet-approaching Jupiter family comets (JFCs) at Mars, Earth, and Venus is 4:2:1 indicating that JFC-related outbursts would be more frequent at Mars than the Earth. The relative numbers of planet-approaching Halley-type comets (HTCs) implies that the respective levels of annual meteor activity at those three planets are similar. We identify several instances where near-comet outbursts (Jenniskens, P.: 1995, Astron. Astrophys. 295, 206–235) may occur. A possible double outburst of this type at Venus related to 45P/Honda-Mrkos-Padjusakova may be observable by the ESA Venus Express spacecraft in the summer of 2006. Similarly, the Japanese Planet-C Venus orbiter may observe an outburst related to 27P/Crommelin’s perihelion passage in July 2011. Several additional opportunities exist to observe such outbursts at Mars from 2019 to 2026 associated with comets 38P/Stephan-Oterma, 13P/Olbers and 114P/Wiseman-Skiff.     

Do comets have chondrules and CAIs? Evidence from the Leonid meteors

Abstract— Chondrules, silicate spheres typically 0.1 to 1 mm in diameter, are the most abundant constituents in the most common meteorites falling on Earth, the ordinary chondrites. In addition, many primitive meteorites have calcium‐aluminum‐rich inclusions (CAIs). The question of whether comets have chondrules or CAIs is relevant to understanding what the interior of a comet is like and what a cometary meteorite might be like. In addition, one prominent model for forming chondrules and CAIs, the X‐wind model, predicts their presence in comets, while most other models do not. At present, the best way to search for chondrules and CAIs in comets is through meteor showers derived from comets, in particular, the Leonid meteor shower. Evidence potentially could be found in the overall mass distribution of the shower, in chemical analyses of meteors, or in light curves. There is no evidence for a chondrule abundance in the Leonid meteors similar to that found in chondritic meteorites. There is intriguing evidence for chondrule‐ or CAI‐sized objects in a small fraction of the light curves, but further work is required to generate a definitive test.     

Is 2329 Orthos a dead comet?

Probably most meteor showers have a cometary origin. Investigation of Near-Earth asteroids' orbital evolution to determine whether they have related meteor showers is necessary to determine which asteroids evolved from comets. The results of calculations show that asteroid Orthos' orbit is an octuple Earth-crosser. Therefore, if Orthos has an old meteoroid stream it may produce eight meteor showers observable on the Earth. The existence of four Orthos' Northern meteor showers is confirmed by our search in the published catalogues of meteor radiants and orbits or in the archives of the IAU Meteor Data Center (Lund, Sweden).     

ON THE FUTURE PROSPECTS OF METEOR DETECTIONS (INVITED REVIEW)

The successful application of modern observing techniques for Leonid storm observations show that meteor (shower) detections will have a bright future if the field will pursue difficult but important questions. How to forecast a satellite threatening meteor storm? What happens to the organic matter in meteors and can this be an important source of prebiotic molecules? What range of variations in composition and morphology exists among cometary grains and what does this tell us about the origin of the solar system? What long-period comets approach Earth orbit and can meteoroid streams provide early warning for giant impacts? What are the sources of interstellar and interplanetary grains? Just to mention a few. To answer these questions will need new technologies and facilities, some of which are being developed for other use. This may include NASA’s Stratospheric Observatory For Infrared and sub-millimeter Astronomy (SOFIA). In addition, big-science space missions can drive the field if meteor detections are an integral part. Special events, such as meteor outbursts and the “artificial meteor” from the reentry of sample return capsules from interplanetary space, can mobilize observing and theoretical efforts. These and other future opportunities are briefly discussed.     

Orthos' meteor showers

Probably the majority of meteor showers has a cometary origin. Investigation of Near-Earth asteroids' orbital evolution to determine whether they have related meteor showers are necessary to determine which asteroids evolved from comets. The results of calculations show that asteroid Orthos' orbit is an octuple Earth-crosser. Therefore, if Orthos has an old meteoroid stream it may produce eight meteor showers observable on the Earth. The existence of four Orthos' Northern meteor showers is confirmed by our search in the published catalogues of meteor radiants and orbits or in the archives of the IAU Meteor Data Center (Lund, Sweden).     

Is 2329 Orthos a dead comet?

Probably most meteor showers have a cometary origin. Investigation of Near-Earth asteroids' orbital evolution to determine whether they have related meteor showers is necessary to determine which asteroids evolved from comets. The results of calculations show that asteroid Orthos' orbit is an octuple Earth-crosser. Therefore, if Orthos has an old meteoroid stream it may produce eight meteor showers observable on the Earth. The existence of four Orthos' Northern meteor showers is confirmed by our search in the published catalogues of meteor radiants and orbits or in the archives of the IAU Meteor Data Center (Lund, Sweden).     

Meteoric Activities of the Last Millennium

We have analyzed the meteor records in the chronicles of the east Asian countries, especially the Korean records. Our results show that the seasonal variation of sporadic meteors has persisted at least for the last two millennia. We also observed the prominent showers such as the Perseids and the Leonids, which are formed by Halley-type comets. We obtained the regression rate of nodal points for the Leonids to be approximately 1.52± 0.04 days per century.     

Tempel—Tuttle彗星与近年的狮子座流星雨

对狮子座流雨的历史进行了回顾和讨论，并利用“彗星－地球轨道分离（CEOS）及地球滞后彗星时间（TE－C）”统计图进行分析，发现几乎所有的狮子座流星都位于一个倾斜的方框内，而这倾斜方框械右边界的斜率大约为15m/s，方框的宽度大约为4yr，它表明，33年一度的狮子座流星雨一般不会有超过4年的爆发期，更细致的分析表明，最强的流星暴位于一弯曲的细窄条带，在慧星一次回归期，亮流星的比例将年衰减，这些事实，可以用运动，碎裂，扩散和尘埃彗尾模型进行解释，由15m/s速度得到的流星体尺度大小也与事实相容，并且，这表明与地球相遇的流星体粒子是以有限的速度偏离彗星时间（TE－C）就越长，由此倾斜方框的存在，可以对未来狮子座流星雨进行了预报，表明在1998－2000年期间将有较强的狮子座流星雨，中心在1999年，至于2000年以后，要在100多年以后才会有较强的流星暴，而狮子座流星雨的辉煌期可以说已经过去。     

NEOCAM: The Near Earth Object Chemical Analysis Mission

The prime measurement objective of the Near Earth Object Chemical Analysis Mission (NEOCAM) is to obtain the ultraviolet spectra of meteors entering the terrestrial atmosphere from ∼125 to 300 nm in meteor showers. All of the spectra will be collected using a slitless ultraviolet spectrometer in Earth orbit. Analysis of these spectra will reveal the degree of chemical diversity in the meteors, as observed in a single meteor shower. Such meteors are traceable to a specific parent body and we know exactly when the meteoroids in a particular shower were released from that parent body (Asher, in: Arlt (ed.) Proc. International Meteor Conference, 2000; Lyytinen and van Flandern, Earth Moon Planets 82–83:149–166, 2000). By observing multiple apparitions of meteor showers we can therefore obtain quasi-stratigraphic information on an individual comet or asteroid. We might also be able to measure systematic effects of chemical weathering in meteoroids from specific parent bodies by looking for correlations in the depletions of the more volatile elements as a function of space exposure (Borovička et al., Icarus 174:15–30, 2005). By observing the relation between meteor entry characteristics (such as the rate of deceleration or breakup) and chemistry we can determine if our meteorite collection is deficient in the most volatile-rich samples. Finally, we can obtain a direct measurement of metal deposition into the terrestrial stratosphere that may act to catalyze atmospheric chemical reactions.     

Search for Past Signs of October Ursae Majorids

A new meteroid stream—October Ursa Majorids—was announced by Japanese observers on Oct. 14–16, 2006 (Uehara et al. 2006). Its weak manifestation was detected among coincidental major meteor showers (N/S Taurids, Orionids), as its meteors radiated from a higher placed radiant on the northern sky. We have tried to find out previous displays of the stream throughout available meteor orbits databases, and among ancient celestial phenomena records. Although we got no obvious identification, there are some indications that it could be a meteor shower of cometary origin with weak/irregular activity, mostly overlayed by regular coincidental meteor showers. With a procedure based on D-criterion (Southworth and Hawkins 1963) we found a few records in IAU MDC database of meteor photographic orbits which fulfill common similarity limits, for October Ursae Majorids. However, their real association cannot be established, yet. With respect to the mean orbit of this stream, we suggest for its parent body a long-period comet.     

Young Meteor Swarms Near the Sun: I. Statistical Correlation of Meteors with Families of Short-Perihelion Comets

We examine the hypothesis about the formation of meteor streams near the Sun. Families of short-perihelion orbit comets, many of which pass just a few radii from the solar surface at perihelion and have high dust production efficiencies, are assumed to be candidates for the parent bodies of these meteor streams. Our statistical analysis of orbital and kinematic parameters for short-perihelion meteoric particles recorded at the Earth and comets from the Kreutz family and the Marsden, Kracht, and Meyer groups led us to certain conclusions regarding the proposed hypothesis. We found a correlation between the ecliptic longitude of perihelion for comet and meteor orbits and the perihelion distance. This correlation may be suggestive of either a genetic connection between the objects of these two classes or the result of an as yet unknown mechanism that equally acts on short-perihelion comet and meteor orbits. A reliable conclusion about this genetic connection can be reached for the meteors that belong to the Arietids stream and the Marsden comet group.     

Double station and spectroscopic observations of the Quadrantid meteor shower and the implications for its parent body

Object 2003 EH₁ was recently identified as the parent body of the Quadrantid meteor shower. The origin of this body is still uncertain. We use data on 51 Quadrantid meteors obtained from double-station video observations as an insight on the parent body properties. A data analysis shows that the Quadrantids are similar to other meteor showers of cometary origin in some aspects, but in others to Geminid meteors. Quadrantid meteoroids have partially lost volatile component, but are not depleted to the same extent as Geminid meteoroids. In consideration of the orbital history of 2003 EH₁, these results lead us to the conclusion that the parent body is a dormant comet.     

Benefits of an impact mission to 3200 Phaethon: nature of the extinct comet and artificial meteor shower

The asteroid 3200 Phaethon is suggested as a candidate for direct impact research. The object is considered to be an extinct comet and the parent of the Geminid meteor shower. One could say that this provides a possible argument for a space mission. Based on such a mission, this paper proposes to investigate the nature of the extinct comet and the additional interesting possibility of artificially generated meteor showers.
Dust trail theory can calculate the distribution of a bundle of trails and be used to show in which years artificial meteors would be expected. Results indicate that meteor showers will be seen on Earth about 200 yr after the event, on 2022 April 12.     

Meteor outbursts from long-period comet dust trails

Long-period comets have narrow one-revolution old dust trails that can cause meteor outbursts when encountered by Earth. To facilitate observing campaigns that will characterize and perhaps help find Earth-threatening, long-period comets from their trace of meteoric debris, we use past accounts of outbursts from 14 different showers to calculate the future dust trail positions near Earth’s orbit. We also examine known near-Earth, long-period comets and identify five potential new showers, which can be utilized to learn more about these objects. We demonstrate that it is the one-revolution trail that is responsible for meteor outbursts. A method that calculates in what year these showers are likely to return and at what hour is presented. The calculations improve on earlier approximate methods that used the Sun’s reflex motion to gauge the trail motion relative to Earth’s orbit.     

A meteoroid stream survey using the Canadian Meteor Orbit Radar: I. Methodology and radiant catalogue

Using a meteor orbit radar, a total of more than 2.5 million meteoroids with masses ∼10⁻⁷ kg have had orbits measured in the interval 2002-2006. From these data, a total of 45 meteoroid streams have been identified using a wavelet transform approach to isolate enhancements in radiant density in geocentric coordinates. Of the recorded streams, 12 are previously unreported or unrecognized. The survey finds >90% of all meteoroids at this size range are part of the sporadic meteoroid background. A large fraction of the radar detected streams have q<0.15 AU suggestive of a strong contribution from sungrazing comets to the meteoroid stream population currently intersecting the Earth. We find a remarkably long period of activity for the Taurid shower (almost half the year as a clearly definable radiant) and several streams notable for a high proportion of small meteoroids only, among these a strong new shower in January at the time of the Quadrantids (January Leonids). A new shower (Epsilon Perseids) has also been identified with orbital elements almost identical to Comet 96P/Machholz.