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1.
Apostolos A. Christou 《Earth, Moon, and Planets》2004,95(1-4):425-431
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. 相似文献
2.
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. 相似文献
3.
Apostolos A Christou 《Icarus》2004,168(1):23-33
We investigate the possibility of detectable meteor shower activity in the atmosphere of Venus. We compare the Venus-approaching population of known periodic comets, suspected cometary asteroids and meteor streams with that of the Earth. We find that a similar number of Halley-type comets but a substantially lesser population of Jupiter family comets approach Venus. Parent bodies of prominent meteor showers that might occur at Venus have been determined based on minimum orbital distance. These are: Comets 1P/Halley, parent of the η Aquarid and Orionid streams at the Earth; 45P/Honda-Mrkos-Pajdusakova which currently approaches the venusian orbit to 0.0016 AU; three Halley-type comets (12P/Pons-Brooks, 27P/Crommelin and 122P/de Vico), all intercepting the planet's orbit within a 5-day arc in solar longitude; and Asteroid (3200) Phaethon, parent of the December Geminids at the Earth. In addition, several minor streams and a number of cometary asteroid orbits are found to approach the orbit of Venus sufficiently close to raise the possibility of some activity at that planet. Using an analytical approach described in Adolfsson et al. (Icarus 119 (1996) 144) we show that venusian meteors would be as bright or up to 2 magnitudes brighter than their Earth counterparts and reach maximum luminosity at an altitude range of 100-120, 20-30 km higher than at the Earth, in a predominantly clear region of the atmosphere. We discuss the feasibility of observing venusian showers based on current capabilities and conclude that a downward-looking Venus-orbiting meteor detector would be more suitable for these purposes than Earth-based monitoring. The former would detect a shower of an equivalent Zenithal Hourly Rate of at least several tens of meteors. 相似文献
4.
In order to assess the possibility of meteoroid streams detectable from the surface of Mars as meteor showers we have derived minimum distances and associated velocities for a large sample of small body orbits relative to the orbits of Mars and the Earth. The population ratio for objects approaching to within 0.2 AU of these two planets is found to be approximately 2:1. The smaller relative velocities in the case of Mars appears to be the main impediment to the detection of meteors in the upper atmosphere of that planet. We identify five bodies, including the unusual object (5335) Damocles and periodic comet 1P/Halley, with relative orbital parameters most suitable to produce prominent meteor showers. We identify specific epochs at which showers related to these bodies are expected to occur. An overview of possible detection methods taking into account the unique characteristics of the Martian environment is presented. We pay particular attention on the effects of such streams on the dust rings believed to be present around Mars. 相似文献
5.
Joseph A. Nuth III John L. Lowrance George R. Carruthers 《Earth, Moon, and Planets》2008,102(1-4):495-504
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. 相似文献
6.
Martin Beech 《Monthly notices of the Royal Astronomical Society》1998,294(2):259-264
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. 相似文献
7.
Štefan Gajdoš 《Earth, Moon, and Planets》2008,102(1-4):117-123
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. 相似文献
8.
E Lyytinen 《Icarus》2003,162(2):443-452
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. 相似文献
9.
P.B. Babadzhanov 《Celestial Mechanics and Dynamical Astronomy》1997,69(1-2):221-234
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. 相似文献
10.
A.A. Christou J. Oberst S. Elgner J. Flohrer A. Margonis J.P. McAuliffe D. Koschny 《Planetary and Space Science》2012,60(1):229-235
We investigate the expected performance of a wide-angle camera in Martian orbit, which, unlike previous cameras that have flown to Mars, is capable of recording meteor activity in that planet's atmosphere. We show that, based on our current understanding of meteor physics and the interplanetary meteoroid population, several meteors will be detected by this instrument during a single nightside pass on a low Martian orbit. The instrument will also record the signatures of meteor showers expected to occur every Martian year (1.88 Earth years). The results of this investigation will test models of the flux of “large” (mm-cm) meteoroids at the orbit of Mars and their interaction with the Martian atmosphere. 相似文献
11.
P. B. Babadzhanov I. P. Williams G. I. Kokhirova 《Monthly notices of the Royal Astronomical Society》2008,386(4):2271-2277
Using the Everhart radau19 numerical integration method, the orbital evolution of the near-Earth asteroid 2003EH1 is investigated. This asteroid belongs to the Amor group and is moving on a comet-like orbit. The integrations are performed over one cycle of variation of the perihelion argument ω. Over such a cycle, the orbit intersect that of the Earth at eight different values of ω. The orbital parameters are different at each of these intersections and so a meteoroid stream surrounding such an orbit can produce eight different meteor showers, one at each crossing. The geocentric radiants and velocities of the eight theoretical meteor showers associated with these crossing points are determined. Using published data, observed meteor showers are identified with each of the theoretically predicted showers. The character of the orbit and the existence of observed meteor showers associated with 2003EH1 confirm the supposition that this object is an extinct comet. 相似文献
12.
The meteoroid streams associated to short-period comets 9P/Tempel 1 (the target of the Deep Impact mission). and 67P/Churyumov-Gerasimenko (the target of the Rosetta mission) are studied. Their structure is overwhelmingly under the
control of Jupiter and repeated relatively close encounters cause a reversal of the direction of the spatial distribution
of the stream relative to the comet* an initial stream trailing the comet as usually seen eventually collapses, becomes a
new stream leading the comet and even splits into several components. Although these two comets do not produce meteor showers
on Earth, this above feature shows that meteor storms can occur several years before the perihelion passage of a parent body. 相似文献
13.
D. J. Asher 《Earth, Moon, and Planets》2008,102(1-4):27-33
The spatial structure of meteor streams, and the activity profiles of their corresponding meteor showers, depend firstly on
the distribution of meteoroid orbits soon after ejection from the parent comet nucleus, and secondly on the subsequent dynamical
evolution. The latter increases in importance as more time elapses. For younger structures within streams, notably the dust
trails that cause sharp meteor outbursts, it is the cometary ejection model (meteoroid production rate as a function of time
through the several months of the comet’s perihelion return, and velocity distribution of the meteoroids released) that primarily
determines the shape and width of the trail structure. This paper describes how a trail cross section can be calculated once
an ejection model has been assumed. Such calculations, if made for a range of ejection model parameters and compared with
observed parameters of storms and outbursts, can be used to constrain quantitatively the process of meteoroid ejection from
the nucleus, including the mass distribution of ejected meteoroids. 相似文献
14.
We consider in this paper the motion of small meteoroids near to the Earth taking into account gravitation, acceleration and heating of particles in the upper atmosphere, and also the processes of thermal radiation, sputtering and evaporation.It is concluded that during an encounter of the Earth with a meteor stream a dust cloud can be formed only at very small geocentric velocities of the particles.We also carry out calculation of the ion-formation rate in the atmosphere due to the collision of ablated meteor atoms and air molecules reflected from a meteoroid with air molecules encountered. Meteor ionization makes the contribution necessary to the maintenance of the high E-region ionization. During annual meteor showers the rate of meteor ion-formation increases by not more than four times. Additional night sources of ionization of air molecules influence the relative number of atmospheric and meteor ions in the E-region. The contribution of the kinetic energy of meteor matter to the heating of the upper atmosphere is evaluated. 相似文献
15.
David D. Meisel Johan Kero Csilla Szasz Vladimir Sidorov Stan Briczinski 《Earth, Moon, and Planets》2008,102(1-4):315-322
In the northern hemisphere, the month of February is characterized by a lack of major meteor shower activity yet a number
of weak minor showers are present as seen by the Kazan radar. Using the Feller transformation to obtain the distribution of
true meteor velocities from the distribution of radial velocities enables the angle of incidence to be obtained for the single
beam AO (Arecibo Observatory) data. Thus the loci of AO radiants become beam-centered circles on the sky and one can, with
simple search routines, find where these circles intersect on radiants determined by other means. Including geocentric velocity
as an additional search criterion, we have examined a set of February radiants obtained at Kazan for coincidence in position
and velocity. Although some may be chance associations, only those events with probabilities of association > 0.5 have been
kept. Roughly 90 of the Kazan showers have been verified in this way with mass, radius and density histograms derived from
the AO results. By comparing these histograms with those of the “background” in which the minor showers are found, a qualitative
scale of dynamical minor shower age can be formulated. Most of the showers are found outside the usual “apex” sporadic source
areas where it is easiest to detect discrete showers with less confusion from the background. 相似文献
16.
P. B. Babadzhanov 《Earth, Moon, and Planets》1996,72(1-3):305-310
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). 相似文献
17.
对近20年来狮子座流星雨的预报工作，进行了系统的阐述和分析。1998年Tempel-Tuttle彗星的回归，再度带来了狮子座流星雨的观测热，也大大促进了对狮子座流星雨预报工作的研究与验证。有的研究在时间预报准确度方面已显示出其模型的优越性，有的在流星雨的强度方面显示出一定的准确度。指出了两大类不同的方法实际上是在三维空间强调了不同的方面。将不同方法的优势结合起来，可能会使流星雨的预报更加成熟。 相似文献
18.
Paul A. Wiegert 《Earth, Moon, and Planets》2008,102(1-4):15-26
The Canadian Meteor Orbit Radar (CMOR) has collected information on a number of weak meteor showers that have not been well
characterized in the literature. A subsample of these showers (1) do not show a strong orbital resemblance to any known comets
or asteroids, (2) have highly inclined orbits, (3) are at low perihelion distances ( AU) and (4) are at small semimajor axes (<2 AU). Though one might conclude that the absence of a parent object could be the
result of its disruption, it is unclear how this relatively inaccessible (dynamically speaking) region of phase space might
have been populated by parents in the first place. It will be shown that the Kozai secular resonance and/or Poynting–Robertson
drag can modify meteor stream orbits rapidly (on time scales comparable to a precession cycle) and may be responsible for
placing some of these streams into their current locations. These same effects are also argued to act on these streams so
as to contribute to the high-ecliptic latitude north and south toroidal sporadic meteor sources. There remain some differences
between the simple model results presented here and observations, but there may be no need to invoke a substantial population
of high-inclination parents for the observed high-inclination meteoroid streams with small perihelion distances. 相似文献
19.
In the fall of 2005, a dedicated meteor observing campaign was carried out by the Panoramic Camera (Pancam) onboard the Mars Exploration Rover (MER) Spirit to determine the viability of using MER cameras as meteor detectors and to obtain the first experimental estimate of the meteoroid flux at Mars. Our observing targets included both the sporadic meteoroid background and two predicted martian meteor showers: one associated with 1P/Halley and a potential stream associated with 2001/R1 LONEOS. A total of 353 images covering 2.7 h of net exposure time were analyzed with no conclusive meteor detections. From these data, an upper limit to the background meteoroid flux at Mars is estimated to be for meteoroids with mass larger than 4 g. For comparison, the estimated flux to this mass limit at the Earth is [Grün, E., Zook, H.A., Fechtig, H., Giese, R.H., 1985. Icarus 62, 244-272]. This result is qualitatively consistent, within error bounds, with theoretical models predicting martian fluxes of ∼50% that at Earth for meteoroids of mass 10−3-101 g [Adolfsson, L.G., Gustafson, B.A.S., Murray, C.D., 1996. Icarus 119, 144-152]. The MER cameras, even using the most sensitive mode of operation, should expect to see on average only one coincident meteor on of order 40-150 h of total exposure time based on these same theoretical martian flux estimates. To more meaningfully constrain these flux models, a longer total integrated exposure time or more sensitive camera is needed. Our analysis also suggests that the event reported as the first martian meteor [Selsis, F., Lemmon, M.T., Vaubaillon, J., Bell, J.F., 2005. Nature 435, 581] is more likely a grazing cosmic ray impact, which we show to be a major source of confusion with potential meteors in all Pancam images. 相似文献
20.
P. B. Babadzhanov 《Earth, Moon, and Planets》1995,68(1-3):165-170
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). 相似文献