The radiant distribution of AMOR radar meteors

Galligan, D. P.; Baggaley, W. J.

doi:10.1111/j.1365-2966.2005.08918.x

Cited by 43 publications

(38 citation statements)

References 13 publications

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“…The more northern of these appears to have a greater intensity than the southern one, and these sources appear weaker than the helion and anti-helion sources. This is in broad agreement with the studies of Taylor and Elford (1998) and Galligan and Baggaley (2005). Additionally, two weaker sources are observed to lie approximately 60 • above and below the ecliptic plane.…”

Section: The Sporadic Radiant Distributionsupporting

confidence: 80%

“…One of the first things to note about Fig. 5 is that all six sporadic sources identified by Galligan and Baggaley (2005) are represented. The helion and anti-helion sources (located approximately 70 • to the left and right of the direction of the Earth's motion) are meteoroids in highly elliptical low inclination orbits (Taylor and Elford, 1998) that strike the Earth postperihelion (in the case of helion source) or pre-perihelion (anti-helion source).…”

Section: The Sporadic Radiant Distributionmentioning

confidence: 99%

“…Figure 5 presents the monthly-mean sporadic meteor radiant distributions of all meteors detected over Ascension Island for each month from January 2005 to December 2006 inclusive. These are derived using geocentric velocity of meteors versus heliocentric longitude and ecliptic latitude based on observations given in Galligan and Baggaley (2005).…”

Section: Observed Meteor Count Ratesmentioning

confidence: 99%

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The sporadic radiant and distribution of meteors in the atmosphere as observed by VHF radar at Arctic, Antarctic and equatorial latitudes

et al. 2009

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Abstract.Results are presented of a study of the temporal and spatial variability in meteor count rate observations from three VHF meteor radars. These radar are located in the Arctic (at Esrange, 68 • N), in the Antarctic (at Rothera, 68 • S) and near the Equator (on Ascension Island, 8 • S). It is found that for all three locations there is a strong diurnal cycle in observed hourly meteor counts and the time of maxima and minima in these counts depends on the month of the year. In addition, at high latitude there is a strong annual cycle in observed monthly-mean meteor counts, whereas for the radar at low latitude there is a semi-annual cycle. At high latitude there is also an annual cycle in the mean height at which meteors are observed. However, no such annual cycle is found in observed meteor count rates from the low latitude radar. The meteor count data from all the radars are combined to investigate the sporadic radiant distribution (i.e. the distribution of direction of arrival on the celestial sphere of sporadic meteors). This combined radiant distribution shows that there are six main source regions for meteors. The latitudinal and temporal dependence in observed meteor count rates appears to result from a combination of the sporadic radiant distribution, annual fluctuations in atmospheric density, the sensitivity of the radar to meteors from different source directions and the temporal and spatial variability in meteor fluxes.

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Section: The Sporadic Radiant Distributionsupporting

confidence: 80%

Section: The Sporadic Radiant Distributionmentioning

confidence: 99%

Section: Observed Meteor Count Ratesmentioning

confidence: 99%

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The sporadic radiant and distribution of meteors in the atmosphere as observed by VHF radar at Arctic, Antarctic and equatorial latitudes

et al. 2009

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“…The north toroidal source was first discovered and fully described in the early 1960s from the analysis of Harvard Radio Meteor Project (Hawkins 1962(Hawkins , 1963, with hints coming from earlier projects such as at Jodrell Bank (e.g., Davies 1957;Davies & Gill 1960). Its counterpart, the south toroidal source was confirmed in a study of meteor orbit surveys by Jones & Brown (1993), and later in the more detailed study of AMOR data by Galligan & Baggaley (2005), or Jicamarca high-power large-aperture radar by Chau et al (2007). The most detailed study of the north toroidal complex so far was presented by .…”

Section: Introductionmentioning

confidence: 69%

“…Re-evaluation of the relative weight at which this dust component and dust from new (Oort cloud) comets contribute at apex (as advocated by Nesvorný et al 2011b), however, needs a separate, dedicated study. It would be advantageous to combine CMOR data with other radars that have different limiting sensitivity for instance the AMOR system (e.g., Galligan & Baggaley 2005) or the MU system (e.g., Kero et al 2012). Nesvorný et al (2010Nesvorný et al ( , 2011a have calibrated the zodiacal cloud parameters using a combination of a dynamical model and infrared measurements from the IRAS spacecraft.…”

Section: Htc Contribution To Other Radiant Source Regionsmentioning

confidence: 99%

Dynamical Model for the Toroidal Sporadic Meteors

Pokorný

Vokrouhlický

Nesvorný

et al. 2014

ApJ

115

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More than a decade of radar operations by the Canadian Meteor Orbit Radar have allowed both young and moderately old streams to be distinguished from the dispersed sporadic background component. The latter has been categorized according to broad radiant regions visible to Earth-based observers into three broad classes: the helion and anti-helion source, the north and south apex sources, and the north and south toroidal sources (and a related arc structure). The first two are populated mainly by dust released from Jupiter-family comets and new comets. Proper modeling of the toroidal sources has not to date been accomplished. Here, we develop a steady-state model for the toroidal source of the sporadic meteoroid complex, compare our model with the available radar measurements, and investigate a contribution of dust particles from our model to the whole population of sporadic meteoroids. We find that the long-term stable part of the toroidal particles is mainly fed by dust released by Halley type (long period) comets (HTCs). Our synthetic model reproduces most of the observed features of the toroidal particles, including the most troublesome low-eccentricity component, which is due to a combination of two effects: particles' ability to decouple from Jupiter and circularize by the Poynting-Robertson effect, and large collision probability for orbits similar to that of the Earth. Our calibrated model also allows us to estimate the total mass of the HTC-released dust in space and check the flux necessary to maintain the cloud in a steady state.

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Interferometric meteor head echo observations using the Southern Argentina Agile Meteor Radar

et al. 2014

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A radar meteor echo is the radar scattering signature from the free electrons generated by the entry of extraterrestrial particles into the atmosphere. Three categories of scattering mechanisms exist: specular, nonspecular trails, and head echoes. Generally, there are two types of radars utilized to detect meteors. Traditional VHF all‐sky meteor radars primarily detect the specular trails, while high‐power, large‐aperture (HPLA) radars efficiently detect meteor head echoes and, in some cases, nonspecular trails. The fact that head echo measurements can be performed only with HPLA radars limits these studies in several ways. HPLA radars are sensitive instruments constraining the studies to the lower masses, and these observations cannot be performed continuously because they take place at national observatories with limited allocated observing time. These drawbacks can be addressed by developing head echo observing techniques with modified all‐sky meteor radars. Such systems would also permit simultaneous detection of all different scattering mechanisms using the same instrument, rather than requiring assorted different classes of radars, which can help clarify observed differences between the different methodologies. In this study, we demonstrate that such concurrent observations are now possible, enabled by the enhanced design of the Southern Argentina Agile Meteor Radar (SAAMER). The results presented here are derived from observations performed over a period of 12 days in August 2011 and include meteoroid dynamical parameter distributions, radiants, and estimated masses. Overall, the SAAMER's head echo detections appear to be produced by larger particles than those which have been studied thus far using this technique.

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The radiant distribution of AMOR radar meteors

Cited by 43 publications

References 13 publications

The sporadic radiant and distribution of meteors in the atmosphere as observed by VHF radar at Arctic, Antarctic and equatorial latitudes

The sporadic radiant and distribution of meteors in the atmosphere as observed by VHF radar at Arctic, Antarctic and equatorial latitudes

Dynamical Model for the Toroidal Sporadic Meteors

Interferometric meteor head echo observations using the Southern Argentina Agile Meteor Radar

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