Perseus Research Articles

Precision of meteor trajectory and orbital measurements by the MIOS

Abstract Measurement errors of meteors can substantially affect the accuracy of meteoroid trajectory and orbit determinations, potentially leading to spurious meteoroid orbits. Here, we evaluate the measurement errors associated with the meteor and ionospheric irregularity observation system (MIOS) developed at low latitude Ledong and Sanya, China, aimed at observing various meteors and their associated plasma density irregularity phenomena, and investigate how these errors affect the determination of meteor trajectories and orbits. The measurement error of meteor position is estimated to be ∼2 pixels, corresponding to 0.04○, which is sufficient to detect true radiant dispersion and structural characteristics in younger meteor showers. By simulating meteoroids from the Draconid, Geminid, and Perseid meteor showers with the ∼2 pixels measurement error and the Monte Carlo trajectory method, the precision of corresponding meteoroid trajectories is derived. The radiant accuracy is 1.09○, with right ascension and declination accuracies of 0.78○ and 0.77○, respectively. The velocity accuracy is 0.64 km/s. The comparison of estimated and true radiant uncertainties shows that the estimated errors of the MIOS are generally consistent with the true meteor trajectory errors. Finally, we estimate the orbital measurement errors, which include an eccentricity of 0.05, a perihelion distance of 0.0086 AU, an inclination of 1.4○, and an argument of the perihelion of 1.86○. Based on observations of eight representative meteor showers during 2019-2023, the accuracy of the MIOS in detecting meteor trajectories and orbits is further validated.

Spatially Resolved Observations of Meteor Radio Afterglows With the OVRO‐LWA

AbstractWe conducted an all‐sky imaging transient search with the Owens Valley Radio Observatory Long Wavelength Array (OVRO‐LWA) data collected during the Perseid meteor shower in 2018. The data collection during the meteor shower was motivated to conduct a search for intrinsic radio emission from meteors below 60 MHz known as the meteor radio afterglows (MRAs). The data collected were calibrated and imaged using the core array to obtain lower angular resolution images of the sky. These images were input to a pre‐existing LWA transient search pipeline to search for MRAs as well as cosmic radio transients. This search detected 5 MRAs and did not find any cosmic transients. We further conducted peeling of bright sources, near‐field correction, visibility differencing and higher angular resolution imaging using the full array for these 5 MRAs. These higher angular resolution images were used to study their plasma emission structures and monitor their evolution as a function of frequency and time. With higher angular resolution imaging, we resolved the radio emission size scales to less than 1 km physical size at 100 km heights. The spectral index mapping of one of the long duration event showed signs of diffusion of plasma within the meteor trails. The unpolarized emission from the resolved radio components suggest resonant transition radiation as the possible radiation mechanism of MRAs.

Meteor cluster event indication in variable-length astronomical video sequences

Abstract In recent years, the study of parallel or cluster meteor events has become increasingly popular. Many imaging systems currently focus on meteor detection, but the algorithms exploiting the data from such systems do not investigate the probability of cluster or parallel meteor events. This paper presents a novel approach to indicate a potential meteor cluster or parallel meteor event based on variable-length astronomical video sequences. The presented algorithm consists of two main parts: meteor event pre-detection and meteor cluster event probability evaluation. The first part of the algorithm involves a meteor pre-detection method based on the Hough transform (HT) and the exact event location within the time domain. In addition to pre-detecting meteor events, the method outputs event trajectory parameters that are further exploited in a second part of the algorithm. This subsequent part of the algorithm then operates over these meteor trajectory parameters and indicates the probability of cluster occurrence. The algorithm is experimentally evaluated on video sequences generated by the Meteor Automatic Imager and Analyzer (MAIA) astronomical imaging system, covering the Draconid and September ε Perseid (SPE) meteor showers. Compared to the current MAIA meteor detection software, the proposed part of the pre-detection algorithm shows promising results, especially the increased rate of correct meteor detection. The meteor cluster evaluation part of the algorithm then demonstrates its ability to successfully select related meteor event candidates (disintegrated from the same parental object) and reject unrelated ones.

Абляция мелких метеорных тел: сравнение модели сплошного и пористого тела

An ablation model is used to describe the interaction of small meteoroids with the Earth’s atmosphere. In this model, the mass loss of a meteoroid is determined using the saturated vapor pressure of the assumed meteoroid substance. The meteoroid is considered in two modifications as a solid and a porous object. An automated method for estimating the parameters of meteoroids (mass, size, and density) from light curves is developed based on the model of small meteor body ablation, which has been used to estimate the parameters of the Perseid meteors with a brightness of -2m to +2m. The effect of the dependence for saturated vapor pressure and the residual on the parameters of the meteoric body is analyzed. It is shown that for the same meteor, the use of different dependences for pressure or different residuals leads to the dispersion of the meteor mass estimate of not more than 10-15% of the average value, and for the meteor size not more than 35-40%. The difference between the maximum and minimum density estimates can be up to five times. The selected dependence for the saturation vapor pressure strongly affects the shape of the light curve, the quality of its approximation, and the density estimate. The average porosity for all meteoroids is 86±5%, which is close to the values for IDP. The density of meteoroids is determined with a large error. The selected model better describes meteoroids with the degree of skewness of the light curve in the range of 0.4 - 0.5. The use of the porous body model has little effect on the mass estimate, while the density estimates increase by up to 2 times.

Ejection velocities, age, and formation process of SPE meteoroid cluster

Context. Meteoroid clusters represent a unique opportunity to study processes of meteoroid disruptions in interplanetary space. We follow our previous work about the September epsilon Perseid (SPE) meteoroid cluster from 2016 with a detailed analysis of the observed data and cluster formation conditions. Aims. Our goal is to determine ejection velocities of the cluster members and SPE’s age, as well as to estimate the most probable formation process. Methods. We precisely determined mutual positions and masses of all meteoroids including the errors. We assumed that the massdominated meteoroid is the parent body of the cluster and that the observed positions of meteoroids are controlled by the ejection velocities and the action of solar radiation pressure. A formula for the dependence of meteoroid ejection velocities on the mutual positions, masses, and cluster age was derived. It was assumed that the time at which the initial kinetic energy of all meteoroids reached a minimum value corresponds to the age of the cluster. Knowing values and directions of ejection velocities together with meteoroid masses then allowed us to determine the most likely process of cluster formation. Results. The meteoroids occupy a volume of 66 × 67 × 50 km and are shifted in the antisolar direction by 27 km relative to the parent meteoroid. The age of the cluster is 2.28 ± 0.44 days. The ejection velocities range from 0.13 ± 0.05 m s−1 to 0.77 ± 0.34 m s−1 with a mean value of 0.35 m s−1. The ejection velocity directions are inside the cone with an apex angle of 101 ± 5°. The axis of the cone is ~45° away from the solar direction and ~34° away from the mean direction of the flux of small meteoroids’ incident on the parent meteoroid. Formation due to the separation of part of the surface due to very fast rotation is the least likely thing to occur. We estimate the rotation frequency to be about 2 Hz and the corresponding stress is several orders of magnitude lower than the predicted strength limit. It is also difficult to explain the formation of the cluster by an impact of a small meteoroid on the parent body. However, this possibility, although not very likely, cannot be completely ruled out. The most probable process is the exfoliation due to thermal stresses. Their estimated magnitude is sufficient and the derived ejection velocities are consistent with this process of formation.

The meteor shower complex of comet 109P/Swift-Tuttle based on its cloned orbits

Comet 109P/Swift-Tuttle is the well-known parent body of the Perseid meteor shower, and, possibly, a few other showers, as we found in our previous work (Paper I). In Paper I, we studied the meteoroid stream of the comet using models derived from the comet’s nominal orbit. In respect to the uncertainty of its determination, the nominal orbit did not appear to be the most probable orbit. Furthermore, our modeling predicted the semi-major axes of Perseids typically larger than the published mean semi-major axis of this shower by some authors. In this paper, we repeat the modeling, in the same way as in Paper I, except we derive the models of the stream from two cloned orbits of the nominal orbit. The first clone attempts to fit the most probable 109P’s orbits and the second clone had, in a certain period in the past, the smallest semi-major axis among all constructed clones. We confirmed the clear relationship of 109P with the Perseids, #7, and, with regard to the stronger influence of non-gravitational forces, its relationship with the 49 Andromedids, #549. Furthermore, we found an indication that parts of the stream meteoroids of 109P, which have long evolutionary periods, may correspond to the ζ-Cassiopeiids, #444, u-Andromedids, #507, and UY Lyncids, #705. However, the modeling based on the cloned orbits did not result, in general, in a better match of our prediction with the real showers (mainly Perseids) than the modeling described in Paper I, which was based on the nominal orbit of 109P.

Meteors with extreme beginning heights from observations with high-sensitivity super-isocon TV systems

ABSTRACT Meteors with extremely high altitudes are considered. Parameters of seven meteors having anomalous beginning heights recorded with highly sensitive super-Isocon TV systems are presented. One 1993 Perseid meteor, one 2001 sporadic meteor and five meteors from the 2002 Leonid storm had beginning heights in the range 135–145 km. The sporadic meteor is used to demonstrate the methods of data processing and observation precision results. The original TV meteor images, photometric calibration curves and meteor light curve are shown. Light curves are shown for the Leonid shower meteors as well. Based on the sporadic meteor and the 2002 Leonid shower meteor data, mass-loss curves were calculated as functions of height and time: the maximum rates of mass loss were 0.14 and 0.20 g s−1, respectively. Using the classic equation for partially isothermal stone particle heating, the detected beginning heights of most meteors considered (136–135 km) are shown to possibly be related to blowing the molten layer off from a meteoroid surface and most segments of the light curves (below 124 km) show intensive evaporation. For some Leonid meteors, appearing higher than 145–140 km, energy exchange of atmosphere molecules and atoms with the ‘cold’ meteoroid surface can also be assumed. Another possible explanation lies in the low melting temperature of 1500–1600 K for Leonid meteors.

Dynamical and physical features of Perseid meteoroids from Tajikistan fireball network observations

ABSTRACTWe present the results of a study of the dynamical and physical properties of large-sized Perseid meteoroids based on optical observations. Photographic observations of the Perseid meteor shower were carried out during the maximum of its activity in 2007–2011 using the Tajikistan fireball network. Multistation images of 29 Perseids recorded during this period were processed. The atmospheric trajectories, velocities, radiants, orbits, photometric masses and densities of the meteoroids were determined using the astrometric and photometric reduction of fireball images. The initial masses of meteoroids that produced fireballs range from several to 20 g. The observed light-curves of the Perseids and the mean bulk density of most meteoroids of ~0.4 g cm−3 are typical for cometary matter. According to the radiants, velocities and orbits, the captured Perseids are related both to the annual component of the stream and to the dust trail ejected by the parent comet 109P/Swift–Tuttle during its last perihelion passage in 1992.

ВИЗНАЧЕННЯ ЕКВАТОРІАЛЬНИХ КООРДИНАТ БОЛІДА ЗА СПОСТЕРЕЖЕННЯМИ ЗІ СТАЦІОНАРНОЮ МАЛОЧУТЛИВОЮ ПОБУТОВОЮ ОХОРОННОЮ ВІДЕОКАМЕРОЮ

Method for determination of equatorial coordinates of a bright bolide detected with wide-angle low-sensitive home guard camera on 9 August 2020 above Kyiv is presented. Due to low sensitivity of the camera there were no objects for comparison in the frames with the bolide, and sky was obstructed more than a half by the crown of threes. For a search of objects of comparison with known equatorial coordinates we proposed to use the images of the Moon and Mars, which systematically got into frames during the next month – September. The corresponding formulae are presented. The precision of the bolide’s equatorial coordinates calculation were tenths of degree at field of view of the camera 100°, and the trajectory angular length was near 15°. The bolide was very slow, and according to calculations did not belong to the Perseid meteor shower, which was active during the observations.

September epsilon Perseids observed by the Czech Fireball Network

We present 25 photographic fireballs belonging to the September epsilon Perseid (SPE, IAU #208) meteor shower observed by the Czech part of the European Fireball Network in 2013–2017. Exceptional high activity of bright photographic fireballs was observed in 2013, while a lower activity, but still higher than in other years, was observed in the period of 2015–2017. Physical properties of these SPE fireballs were studied and compared to other meteor showers. Perseids are found to be the closest analog to SPE. Corrected geocentric radiant of the 2013 outburst fireballs was determined for solar longitude 167.20° and has right ascension 47.67 ± 0.04° and declination 39.493 ± 0.013° (J2000.0). On the basis of determined heliocentric orbits the parent body of the shower is an unknown long-period comet on retrograde orbit with an orbital period of the order of a thousand years.

Characterisation of the Perseid meteoroid stream through SPOSH observations between 2010–2016

We have characterised the Perseid meteoroid stream from data acquired in a series of observing campaigns between 2010 and 2016. The data presented in this work were obtained by the Smart Panoramic Optical Sensor Head (SPOSH), an all-sky camera system designed to image faint transient noctilucent phenomena on dark planetary hemispheres. For the data reduction, a sophisticated software package was developed that utilises the high geometric and photometric quality of images obtained by the camera system. We identify 934 meteors as Perseids, observed over a long period between late July (~124°) and mid-to-late August (~147°). The maximum meteor activity contributing to the annual shower was found at λ⊙ = 140°.08 ± 0°.07. The radiant of the shower was estimated at RA = 47°.2 and Dec = 57°.5 with a median error of 0°.6 and 0°.2, respectively. The mean population index of the shower between solar longitudes of 120°.68 and 145°.19 was r = 2.36 ± 0.05, showing strong temporal variation. A predicted outburst in shower activity for the night of August 11–12, 2016 was confirmed, with a peak observed 12.75 hr before the annual maximum at 23:30 ± 15′ UT. We measure a peak flux of 6.1 × 10−4 km−2 hr−1 for meteoroids of mass 1.6 × 10−2 g or more, appearing in the time period between 23:00 and 00:00 UT. We estimate the measured flux of the outburst meteoroids to be approximately twice as high as the annual meteoroid flux of the same mass. The population index of r = 2.19 ± 0.08, computed from the outburst Perseids in 2016, is higher than the value of r = 1.92 ± 0.06 derived from meteors observed in 2015 belonging to the annual Perseid shower which was active near the time of the outburst. A dust trail with an unusually high population index of r = 3.58 ± 0.24 was encountered in 2013 between solar longitudes 136°.261 and 137°.442. The relatively high r-value implies an encounter with a dust trail rich in low-mass particles.

Evaluating Strategies To Collect Micrometeorites From Rainwater For Citizen Scientists

Micrometeorites originate from small pieces of rock from space colliding with the Earth’s atmosphere at high velocity, such as the Perseid meteors which hit the atmosphere at 60 km/s. When they do so, they burn up, causing a flash of light that we see as a meteor. Many groups have been successful collecting these particles using various devices. Such activities make great science projects for middle and high school students, and we plan to start a program to train students in the collecting methods and get them interested in science, technology, engineering and math (STEM) careers. Various methods are used to collect micrometeorites from rainwater, but little work has been done to assess the most efficient method of collecting these particles from space and then analyzing them. Before we began our citizen science project, we determined that it was necessary to conduct a pilot project to determine the most effective method of collecting micrometeorites from rainwater. Four collecting methods were tried and the method that collected the most micrometeorites was also the simplest, that being a simple bucket under the downspout of the gutter system of a house and a magnet which is then run through the bucket to gather the meteorites.

Perseid Meteor Shower To Reach Peak August 12-13: Here's How To See It

Perseid Meteor Shower To Reach Peak August 12-13: Here's How To See It

Analysis of the September ε-Perseid outburst in 2013

We analyze the outburst experienced by the September $\varepsilon$-Perseid meteor shower on 9 September 2013. As a result of our monitoring the atmospheric trajectory of 60 multi-station events observed over Spain was obtained and accurate orbital data were derived from them. On the basis of these orbits, we have tried to determine the likely parent body of this meteoroid stream by employing orbital dissimilarity criteria. In addition, the emission spectra produced by two events belonging to this meteor shower were also recorded. The analysis of these spectra has provided information about the chemical nature of their progenitor meteoroids. We also present an estimation of the tensile strength for these particles.

A meteoroid stream survey using meteor head echo observations from the Middle Atmosphere ALOMAR Radar System (MAARSY)

Results from a meteor head echo shower survey using the quasi continuous meteor observations of the high power large aperture radar MAARSY, located in northern Norway (69.30°N, 16.04°E) are presented. The data set comprises 760 000 head echoes detected during two and half years sensitive to an effective limiting masses below 10−8 kg. Using a wavelet shower search algorithm, we identified 33 meteor showers in the data set all of which are found in the IAU meteor shower catalog. We find ∼ 1% of all measured head echoes at these masses are associated with meteor showers. Comparison of shower radiants from this survey with the observation of the Canadian Meteor Orbit radar (CMOR) transverse scattering radar system shows generally good agreement, although there are large differences in the measured durations of some meteor showers. Differential mass indices (s) of ∼ 1.5–1.6 are measured for the Perseids (PER), Geminids (GEM) and Quadrantids (QUA) showers. The Orionids (ORI) show a much steeper mass index of 2.0, in agreement with other observations at small particle sizes, suggesting the Halleyid showers, in particular, are rich in very small meteoroids.

МЕТЕОРИ З МУЛЬТИМОДАЛЬНИМИ КРИВИМИ БЛИСКУ: СПОСТЕРЕЖЕННЯ ТА ЯКІСНІ МОДЕЛІ

The problem of TV or video registration of meteors with anomalous light curves, in particular with multimodal and bimodal types is considered. The results of observations of two meteors from Perseid shower, obtained with the help of TV systems of super-isocon type are presented. The initial velocities of meteors were typical for Perseid shower meteors: 62.4 km/s and 58.4 km/s. One of the meteors has a light curve of a multimodal character, which can be explained by the fragmentation of the body. Another light curve has an evident bimodal type, which has no final explanation for the present. In opposite to most of registered for the moment meteors with bimodal light curves the given meteor from Perseid shower demonstrates the first peak of illumination to be much more intensive, and the second one to be significantly lower. The maximal brightness in the first peak was +2 magnitude, in the second one +3.5 magnitude, and in depression +4.5 magnitude which almost corresponds to the sky background, while the sensitivity of our observational instruments was +5.5 magnitude; but nevertheless the entire radiation disappearance was not happen. The qualitative models for interpretation of the meteor with bimodal light curve are proposed. One of them stipulates for different variants of realization of the 2-components composition of a meteoroid, when a body as the matter of fact consists of two particles. One of particles, inner as a rule, is high melting, for example a stone of iron; another one, the cover, is lower melting, for example a mix of dust and ice. Other types of the models use the cases of uniform monolith meteoroid of specific geometric shape. It is also intended that the meteoroid can rotate during its motion dependently on changing body shape or shifting its mass center. The proposed models are the simplest in accordance with the number of varying parameters, and can therefore pretend to their reality after successful application of quantitative analysis and according numerical modeling. It is noted that the final confirmation or abolishment of the model type will be possible after carrying out parallel spectral observations of meteors.

Starry Eyes by Jenn Bennett

Reviewed by: Starry Eyes by Jenn Bennett Kate Quealy-Gainer Bennett, Jenn Starry Eyes. Simon Pulse, 2018 [432p] Trade ed. ISBN 978-1-4814-7880-9 $17.99 E-book ed. ISBN978-1-4814-7882-3 $10.99 Reviewed from galleys Ad Gr. 9-12 Control freak Zorie is not looking forward to a weekend camping trip with her best friend, and she's especially not happy when Lennon, the boy who broke her heart last year, joins their group as their unofficial wilderness guide. Still, best pal Reagan is having a rough year, so Zorie's willing to go along with it out of BFF loyalty, and as an astronomy nerd she's excited about seeing the upcoming Perseid meteor shower. A spat leads the rest of the group to split off from Zorie and Lennon, but Zorie still hopes to see the Perseids, so Lennon is game to guide her on the long trek to the highest viewing spot. The book is loaded with contrivance: it's unclear how the rest of the group makes their way back through the woods without Lennon since they needed him in the first place, Zorie's decision to hike days to the peak is wildly out of character, and her inability to do anything right camping-wise is grating. That's mostly backdrop to Zorie and Lennon's reunion story, though, which is one with witty love/hate banter and plenty of intense make-up sex. There's humor in Lennon's background (his parents run the sex toy shop next to Zorie's parents' acupuncture place), drama in Zorie's family life (her dad is a serial cheater), and plenty of non-sexual thrills in the various forest threats, making for an acceptable romance read, especially under starry skies. KQG [End Page 323] Copyright © 2017 The Board of Trustees of the University of Illinois

Networks of cameras are tracking meteorites with unprecedented precision

Networks of cameras are trained on the skies in hopes of gathering meteorite samples—from events such as the Perseid Meteor Shower shown here—that can help researchers understand the rocks' origins, frequency, and composition. Image courtesy of NASA/JPL.

Video Observation of Perseids meteor shower 2016 from Egypt

Abstract The results of single television observations of Perseid meteor shower in 2016 are presented. The Perseid shower occurs from 17 July to 24 August, peaking on or around August 12 every year. In 2016, the peak of the Perseids was Night of Aug 11 to the morning of Aug 12. The meteor video observations in Egypt are carried out at The National Researcher Institute of Astronomy and Geophysics (NRIAG). The system consists of TV - cameras Watec -902H Ultimate with the lens DV10x8SA-1 (8-80 mm (10x)) capable of recording the rapid motion of meteors entering the Earth atmosphere.

September epsilon Perseid cluster as a result of orbital fragmentation

Context. A bright fireball was observed above the Czech Republic on September 9, 2016, at 23:06:59 UT. Moreover, the video cameras at two different stations recorded eight fainter meteors flying on parallel atmospheric trajectories within less than 2 s. All the meteors belong to the September epsilon Perseid meteor shower. The measured proximity of all meteors during a very low activity meteor shower suggests that a cluster of meteors was observed.Aims. The goal of the paper is first to determine whether this event was a random occurrence or a real meteor cluster and second, if it was a cluster, to determine the epoch and at what distance from the Earth the separation of the particles occurred.Methods. The atmospheric trajectories of the observed meteors, masses, and relative distances of individual particles were determined using a double-station observation. According to the distances and masses of the particles, the most probable distance and time of fragmentation is determined.Results. The observed group of meteors is interpreted as the result of the orbital fragmentation of a bigger meteoroid. The fragmentation happened no earlier than 2 or 3 days before the encounter with the Earth at a distance smaller than ~0.08 AU from the Earth.