Leonid Meteor Research Articles

Recovering Data of an Observation of the Leonids in 1869 from the Lisbon Geophysical Observatory (Portugal)

The Leonid meteor shower is renowned for its scientific and public interest. In a search for meteorological data from Portuguese stations, records on an observation of the Leonids in 1869 from the Lisbon Geophysical Observatory “Infante Dom Luiz” were found. Given their potential value, a digital version with metadata is provided in the present note (the recovered data are available on doi:10.5281/zenodo.11221019). The observation took place from 9 PM on 1869 November 13 to 6 AM on November 14, local time in Lisbon, with mostly clear skies and 4–5 observers covering completely the sky. They recorded 1980 meteors, noting Zodiacal Light visibility and detailing meteor counts every five minutes.

Robert Frost and the Leonid Meteor Shower

Robert Frost (1874–1963) enjoyed a lifelong interest in astronomy, and a number of his works refer to astronomical phenomena and to our propensity to look for meaning in them. Frost’s poem ‘A Loose Mountain (Telescopic)’, published in 1942, provides an apt—and humorous—description of the Leonid meteor shower. Aspects of the poem suggest Frost was inspired by the complex history of the Leonids, and in particular, the failure of the Leonid ‘storm’ to appear as predicted in 1899. Like the old constellation myths, the poem tells a story that helps us understand and remember a night-sky phenomenon. It also invites us to think about our relationship to the night sky, and warns us, with references to Milton’s Paradise Lost, against losing our connection with it.

Multi-instrumental detection of a fireball during Leonids of 2019

During the 2019 Leonid meteor shower, the European Fireball Network recorded a bright fireball (meteor code: EN171119_041459) at 04:15:0.2 (UT) on 17 November 2019. The fireball appeared at coordinates 49.95°N 15.56°E at the height of 134.46 km, and disappeared at coordinates 50.23°N 15.26°E and at the height of 71.81 km. The ionization effect caused by the fireball appeared in the digisonde’s campaign measurements taken with a 2 ionogram/min time resolution at Průhonice station (50.00°N, 14.60°E). The trace appeared on the ionograms as a faint sporadic E-like layer, and the maximum ionization reached the upper limit of the measurement, 17 MHz. The trace persisted for 20 min on the ionograms, first appearing at 04:15:40 (UT) and finally disappearing at 04:35:40 (UT). The virtual height of the trace according to the ionograms appeared between 114 and 142 km, first it descended and then it ascended. Drift measurements were also taken with the digisonde every minute. Between 04:19:20 and 04:35:20 (UT), between altitudes of 122–142 km, 1-5 reflections were recorded on most SkyMaps. In addition, the Continuous Doppler Sounding developed by the Institute of Atmospheric Physics CAS also recorded the ionization signature of the fireball between 04:18 and 04:30 (UT) on 2 of the 3 sounding paths operating at 4.65 MHz. This is the first evidence that the plasma trail of a documented fireball can be detected by a DPS-4D digisonde (not only on ionograms, but also by drift measurements) and by the Continuous Doppler Sounding system.

Daily distribution of meteor flight frequency according to radio observations

The paper considers the problem of studying the daily distribution of the passage of meteoroids by radio observation. The advantages of the chosen method of registration over the classical optical and photographic methods of observation are considered. A voluminous series of data was obtained using a registration facility implemented on the basis of the Center for Astrophysical Research at the North Kazakhstan University named after Manash Kozybayev. Processing, analysis and systematization of the obtained data on meteor phenomena have been carried out. Based on the obtained observational data, on the basis of the Center for Astrophysical Research at the North Kazakhstan University named after Manash Kozybayev, using the Multi VirAnalyzer program, namely the Date Recorder, the daily distribution of the meteor flight frequency was calculated. Also, with the help of the Microsoft Excel software application, diagrams of the daily distribution of the meteor passage frequency were constructed. During the analysis of the obtained diagrams of the daily distribution of the meteor passage frequency, the peak and average daily values of meteor activity were determined. Based on the daily distribution, diagrams of the frequency of meteor passages were constructed for certain months during which the Perseid and Leonid meteor showers are active. A clear correlation with the results of studies of other laboratories of a similar line of research is shown.

TALES FROM INDIA. 1: METEOR SHOWERS IN CLASSICAL AND COLONIAL SOURCES

Meteor phenomena are always fascinating and capture popular attention. This paper reports results of a search for references to and records of meteor showers observed in the Indian region, until the close of the nineteenth century. The sources explored were the Indian classics and chronicles, institutional reports and accounts by individuals, including those published in professional journals. We found very few references to such events in the classical sources. The earliest datable references that we found were in Shuka's <italic>Rajatarangini</italic> (Perseids or Leonids, 1533), Abu'l Fazl's <italic>Akbarnama</italic> (Alpha Capricornids or Delta Aquarids, 1592) and in Krishnaji Sabhasad's account of the life of Chhatrapati Shivaji Maharaj (Leonids, 1680). The subsequent accounts belong to the nineteenth century. Some of these are about sporadic meteors, while others are about meteor showers. The earliest published report is of the November Leonid meteor shower of 1832. We also came across a strong meteor shower on 10 September 1841 reported in the 13 September issue of the <italic>Englishman</italic> newspaper. We believe this is the September Epsilon Perseids, a minor shower known to peak on 9/10 September. This 1841 observation is 37 years before the September Epsilon Perseids were first described by William Denning, in 1878. We believe that such records can be of great value in fine-tuning time-lines in Indian history and understanding the dynamics of meteoroid streams.

Probing plasma physics and elemental composition of a leonid meteor by fitting complex plasma radiation model parameters

ABSTRACT A numerical simulation model was developed and employed in elemental composition determination and characterization of meteor plasma physical parameters, particularly the plasma excitation temperature and electron density, by fitting the model parameters to the emission spectrum of a bright Leonid bolide recorded in the visible spectral range. Novel model introduced in this study involves self-absorption and enables parallel optimization of tens of the parameters. We also discuss that the observed bolide spectrum is strongly dependent on observation geometry.

Prediction of meteoroid stream structure based on meteoroid fragmentation

Every day, large number of meteoroids enter the Earth’s atmosphere and deposit their mass either in atomic form or in ionic form depending on whether it has undergone ablation or fragmentation. The heavier meteoroids undergo fragmentation while the lighter ones are more prone to ablate. In this paper, we would like to speculate meteoroid stream structure of Leonid meteor shower based on fragmenting meteoroids. A 23 revolutions old meteoroid trail left behind by the comet 55P/Tempel-Tuttle in the year 1213 AD, which instigated Leonid meteor shower in the year 2010 is considered for our study. We have calculated mass of the meteoroids, echo durations and percentage of fragmentation. From the observed echo durations of meteoroids, estimated masses and from the percentage of fragmentation, we visualize the stream structure to be like the lighter particles wrapping up the heavier ones. The results we draw from these three different studies are matching with each other. To our knowledge, we are the first to speculate on the meteor stream structure based on fragmentation and making it a new tool in meteor stream evolution. Based on echo durations, it has been observed that 72% of the activity during the shower is contributed by lighter particles of the stream. It is found that about 20% of the meteoroids have undergone fragmentation indicating the minimal role of heavier particles (> $$10^{-6}$$ g) during Leonid Meteor Shower (LMS). The masses of the meteors are estimated to be in the range of $$10^{-10}$$ – $$10^{-5}$$ g.

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.

John Couch Adams: mathematical astronomer, college friend of George Gabriel Stokes and promotor of women in astronomy.

John Couch Adams predicted the location of Neptune in the sky, calculated the expectation of the change in the mean motion of the Moon due to the Earth's pull, and determined the origin and the orbit of the Leonids meteor shower which had puzzled astronomers for almost a thousand years. With his achievements Adams can be compared with his good friend George Stokes. Not only were they born in the same year but were also both senior wranglers, received the Smith's Prizes and Copley medals, lived, thought and researched at Pembroke College, and shared an appreciation of Newton. On the other hand, Adams' prediction of Neptune's location had absolutely no influence on its discovery in Berlin. His lunar theory did not offer a physical explanation for the Moon's motion. The origin of the Leonids was explained by others before him. Adams refused a knighthood and an appointment as Astronomer Royal. He was reluctant and slow to publish, but loved to derive the values of logarithms to 263 decimal places. The maths and calculations at which he so excelled mark one of the high points of celestial mechanics, but are rarely taught nowadays in undergraduate courses. The differences and similarities between Adams and Stokes could not be more striking. This volume attests to the lasting legacy of Stokes' scientific work. What is then Adams' legacy? In this contribution, I will outline Adams' life, instances when Stokes' and Adams' lives touched the most, his scientific achievements and a usually overlooked legacy: female higher education and support of a woman astronomer. This article is part of the theme issue 'Stokes at 200 (part 2)'.

Initial Results of Meteor Wind with Langfang Medium Frequency Radar

We conducted meteor observations during the Leonid meteor shower on 16 November 2017 and 17 November 2018 with Langfang medium frequency (MF) radar (116° E, 40° N). This was the first nighttime meteor observation by MF radar in mid-latitude China. The observation period was 12:00–22:00 (UT) and the observation range was 78–150 km. By using broad vertical beams, totally 94 and 92 meteor echoes were obtained, along with their spatial, time and height distribution. Quite a few meteor echoes are within 30° zenith angles, from the southwest direction, and with a mean height of 107 km which is almost 10 km higher than traditional VHF (Very High Frequency) meteor radar observations. Initial bi-hourly and nightly averaged wind profiles were calculated, and well fitted the wind estimations by co-located VHF meteor radar at the altitude of 100–110 km. On the other side, echoes around 140 km are successfully detected in our observation, which may suggest that for most running MF radars, meteor echoes around 140 km altitude could be detected with a sampling pulse frequency less than 100 Hz.

A comparison of ELF/VLF signals generated by different types of meteor showers

Understanding the meteoroids environment and their properties are important for several fields such as solar system evolution and space science. The investigation of their emissions helps to a better understanding of the physics of meteors and their interactions with the atmosphere. We have compared the ELF/VLF signals generated by Perseids-2016, Leonids-2018 and Geminids-2018 meteors. The results show that a typical meteor generated by small meteoroids, can produce ELF/VLF signals just like brighter fireballs but with lower amplitude and time duration. Also, the results show that the ELF/VLF waves which are generated by Leonids meteors are signals with the most during the effective time and maximum signals per minutes. The results also show that the PER’s and GEM’s signals are a combination of several separated smaller signals. The typical meteor signals have the frequency ranges below 2 kHz but GEM’s meteors generated signals in 3 minutes which have the frequency range up to 4.5 kHz.

Proton-induced halo formation in charged meteors

Despite a very long history of meteor science, our understanding of meteor ablation and its shocked plasma physics is still far from satisfactory as we are still missing the microphysics of meteor shock formation and its plasma dynamics. Here we argue that electrons and ions in the meteor plasma above $\sim$100 km altitude undergo spatial separation due to electrons being trapped by gyration in the Earth's magnetic field, while the ions are carried by the meteor as their dynamics is dictated by collisions. This separation process charges the meteor and creates a strong local electric field. We show how acceleration of protons in this field leads to the collisional excitation of ionospheric N$_2$ on the scale of many 100 m. This mechanism explains the puzzling large halo detected around Leonid meteors, while it also fits into the theoretical expectations of several other unexplained meteor related phenomena. We expect our work to lead to more advanced models of meteor-ionosphere interaction, combined with the electrodynamics of meteor trail evolution.

Leonids in the IAU MDC database

The structure of the Leonid meteor stream was studied using the IAU MDC Photographic Orbits Database. Two notable peaks of activity of photographic Leonids were identified at λ⊙ = 234.5° and λ⊙ = 235.5°. Two smaller peaks were tentatively found at λ⊙ = 236.6° and λ⊙ = 235.9°. The first identified peak of the shower activity is formed merely by the meteors observed in the year 1998; the second one is composed mainly of Leonids observed in the years 1998 and 1999. The smaller peaks of activity are formed by the meteors observed in the years 2001 and 2002. The peaks of activity of three different types of meteors - photographic, visual, and radar as well, were in the year 1999 observed almost at the same solar longitude. This feature of the Leonid trail which caused the 1999 shower is in contrast to many other meteor streams (e.g. Orionids) that are characterized by a shift in the peak of activity depending on the mass of recorded meteoroids. In a comparison with other showers with comparable numbers of meteors listed in the IAU MDC database, the Leonids seems to have an incomparable inner structure. Each of six identified associations of orbits is composed of meteors observed mainly in one individual year. Declination of two associations composed of meteors observed mainly from 1999 does not fit the theoretical trend of the daily motion of the radiant. The results confirm the observation of a spatially separated dust trail of Leonids in 1999.

Calibration-free quantitative elemental analysis of meteor plasma using reference laser-induced breakdown spectroscopy of meteorite samples

Aims. We aim to analyse real-time Perseid and Leonid meteor spectra using a novel calibration-free (CF) method, which is usually applied in the laboratory for laser-induced breakdown spectroscopic (LIBS) chemical analysis. Methods. Reference laser ablation spectra of specimens of chondritic meteorites were measured in situ simultaneously with a high-resolution laboratory echelle spectrograph and a spectral camera for meteor observation. Laboratory data were subsequently evaluated via the CF method and compared with real meteor emission spectra. Additionally, spectral features related to airglow plasma were compared with the spectra of laser-induced breakdown and electric discharge in the air. Results. We show that this method can be applied in the evaluation of meteor spectral data observed in real time. Specifically, CF analysis can be used to determine the chemical composition of meteor plasma, which, in the case of the Perseid and Leonid meteors analysed in this study, corresponds to that of the C-group of chondrites.

THE EFFECT OF MAJOR METEOR STREAMS ON THE TOTAL OZONE IN THE EARTH’S ATMOSPHERE

The correlation between the total ozone and activity of major meteor streams, such as the Perseids, Geminids, Leonids and Orionids, has been found using the Total Ozone Mapping Spectrometer (TOMS) measurements of the global ozone distribution over the periods 1978 − 1993 and 1996 − 2001. The autocorrelation analysis of the total ozone time series for the period of about 20 years has confirmed the existence of regular changes in the ozone levels at the peaks of meteor shower activity. It has been established that TO decreases after the dates of peak activity of meteor streams (e.g. the Perseids) or during the whole periods of meteor shower activity (e.g. the Geminids, Orionids and Leonids). The analysis of the total ozone distribution (in the Southern and Northern Hemispheres), as well as the local distribution of ozone (over the selected surface area of several hundred square kilometres), was performed during the Leonid meteor shower in 1999. The atmospheric zones for which the ozone distribution pattern can be described as a result of interaction between the meteor shower material and the ozone layer were localised by applying the TOMS data. Such zones correspond to the regions where the highest Leonid activity has been observed. According to the radar observations (conducted in Kazan, Russian Federation), three activity maxima of the 1988 Geminid shower were reported: on the nights of 7th, 12th and 14th December, 1988. The TO decrease was observed on the same dates. Thus, the analysis of the TO changes during the periods of intense meteor shower’s activity enables to preliminary assess the maximum overall decline in the total ozone concentration which makes about 5 DU over two weeks. From the results obtained it can be inferred that the ozone layer can be used as an indicator of the interaction between the meteoric material and the Earth’s atmosphere.

Falling Stars as Seen From the Balloon

T ravels in the Air is a 19th-century narrative of balloon ascents by meteorologist James Glaisher (1809-1903), astronomer Camille Flammarion, science journalist Wilfrid de Fonvielle, and chemist Gaston Tissandier. Falling Stars as Seen From the Balloon, by Albert Tissandier (18391906), is a chromolithograph from Travels in the Air that illustrates de Fonvielle’s balloon flight of November 14-15, 1867, to view the Leonid meteor shower. In this romantically shaded image, the trajectories of several meteors are superimposed in the night sky. In 1867 an observer would have had to look directly into the moonlight to see the Leonids, but hundreds of meteors were visible despite the glare. De Fonvielle was born in Paris, France, in 1826. He was a student of mathematics in 1848 when the citizens of Paris rebelled against the monarchy of King Louis Philippe. In the subsequent suppression, De Fonvielle, who was a staunch supporter of the insurrection, was arrested and expelled from the country. Eventually he was allowed to return to France, where he became a writer and editor for the scientific publications La Nature, L'Aerophile, and Lumiere Electrique. During the 1850s De Fonvielle made scientific observations in gasfilled balloons. His flight of November 14-15, 1867, was in a small balloon called L'hirondelle. There was just room in the basket for provisions, warm clothing, scientific instruments, and three men: de Fonvielle, the balloon’s owner, and an American aeronaut who wore a parachute and offered to jump out (in poor light, over unknown terrain) if there was a need to lighten the craft. After filling the balloon with hydrogen gas, the aeronauts ascended in the dark, admiring the lights of Paris as

Strong E region ionization caused by the 1767 trail during the 2002 Leonids

AbstractIntensive E region ionization extending up to 140 km altitude and lasting for several hours was observed with the European Incoherent Scatter (EISCAT) UHF radar during the 2002 Leonids meteor shower maximum. The level of global geomagnetic disturbance as well as the local geomagnetic and auroral activity in northern Scandinavia were low during the event. Thus, the ionization cannot be explained by intensive precipitation. The layer was 30–40 km thick, so it cannot be classified as a sporadic E layer which are typically just a few kilometers wide. Incoherent scatter radars have not to date reported any notable meteor shower‐related increases in the average background ionization. The 2002 Leonids storm flux, however, was so high that it might have been able to induce such an event. The Chemical Ablation Model is used to estimate deposition rates of individual meteors. The resulting electron production, arising from hyperthermal collisions of ablated atoms with atmospheric molecules, is related to the predicted Leonid flux values and observed ionization on 19 November 2002. The EISCAT Svalbard Radar (ESR) located at some 1000 km north of the UHF site did not observe any excess ionization during the same period. The high‐latitude electrodynamic conditions recorded by the SuperDARN radar network show that the ESR was within a strongly drifting convection cell continuously fed by fresh plasma while the UHF radar was outside the polar convection region maintaining the ionization.

Meteor radar wind over Chung-Li (24.9°N, 121°E), Taiwan, for the period 10-25 November 2012 which includes Leonid meteor shower: Comparison with empirical model and satellite measurements

The neutral winds in the mesosphere and lower thermosphere (MLT) region are measured by a newly installed meteor trail detection system (or meteor radar) at Chung-Li, Taiwan, for the period 10–25 November 2012, which includes the Leonid meteor shower period. In this study, we use the 3 m field-aligned plasma irregularities in the sporadic E (Es) region in combination with the International Geomagnetic Reference Field model to calibrate the system phase biases such that the true positions of the meteor trails can be correctly determined with interferometry technique. The horizontal wind velocities estimated from the radial velocities of the meteor trails and their locations by using a least squares method show that the diurnal tide dominates the variation of the MLT neutral wind with time over Chung-Li, which is in good agreement with the horizontal wind model (HWM07) prediction. However, harmonic analysis reveals that the amplitudes of the mean wind, diurnal, and semidiurnal tides of the radar-measured winds in height range 82–100 km are systematically larger than those of the model-predicted winds by up to a factor of 3. A comparison shows that the overall pattern of the height-local time distribution of the composite radar-measured meteor wind is, in general, consistent with that of the TIMED Doppler Interferometer-observed wind, which is dominated by a diurnal oscillation with downward phase progression at a rate of about 1.3 km/h. The occurrences of the Es layers retrieved from fluctuations of the amplitude and excess phase of the GPS signal received by the FORMOSAT-3/COSMIC satellites during the GPS radio occultation (RO) process are compared with the shear zones of the radar-measured meteor wind and HWM07 wind. The result shows that almost all of the RO-retrieved Es layers occur within the wind shear zones that favor the Es layer formation based on the wind shear theory, suggesting that the primary physical process responsible for the Es layer events retrieved from the scintillations of the GPS RO signal is very likely the plasma convergence effect of the neutral wind shear.

The unexpected 2012 Draconid meteor storm

An unexpected intense outburst of the Draconid meteor shower was detected by the Canadian Meteor Orbit Radar (CMOR) on October 8, 2012. The peak flux occurred at ~16:40 UT on October 8 with a maximum of 2.4 +/- 0.3 hr-1 km-2 (appropriate to meteoroid mass larger than 10-7 kg), equivalent to a ZHRmax = 9000 +/- 1000 using 5-minute intervals, using a mass distribution index of s = 1.88 +/- 0.01 as determined from the amplitude distribution of underdense Draconid echoes. This makes the out- burst among the strongest Draconid returns since 1946 and the highest flux shower since the 1966 Leonid meteor storm, assuming a constant power-law distribution holds from radar to visual meteoroid sizes. The weighted mean geocentric radiant in the time interval of 15-19h UT, Oct 8, 2012 was {\alpha}g = 262.4 +/- 0.1 deg, {\delta}g = 55.7 +/- 0.1 deg (epoch J2000.0). Visual observers also reported increased activity around the peak time, but with a much lower rate (ZHR 200), suggesting that the magnitude-cumulative num- ber relationship is not a simple power-law. Ablation modeling of the observed meteors as a population does not yield a unique solution for the grain size and distribution of Draconid meteoroids, but is consistent with a typical Draconid meteoroid of mtotal between 10-6 to 10-4 kg being composed of 10 - 100 grains. Dynamical simulations indicate that the outburst was caused by dust particles released during the 1966 per- ihelion passage of the parent comet, 21P/Giacobini-Zinner, although there are dis- crepancies between the modelled and observed timing of the encounter, presumably caused by approaches of the comet to Jupiter during 1966-1972. Based on the results of our dynamical simulation, we predict possible increased activity of the Draconid meteor shower in 2018, 2019, 2021 and 2025.

Investigation on spectral character of ELF electromagnetic radiations during Leonid 2009 meteor shower

There are several reports of simultaneous optical flashes as well as audible sounds called electrophonics during the passage of meteors through the Earth’s atmosphere, but the exact physical mechanism behind these phenomena is still poorly understood. Some experiments performed during meteor showers indicate the presence of ELF-VLF electromagnetic waves generated simultaneously with the passage of a meteor, which after suitable transduction are converted into audible sound waves. In this context, the present paper investigates the temporal and spectral character of ELF electromagnetic waves produced during the Leonid meteor shower on 18th November, 2009. A well calibrated broadband GPS locked software receiver was used to perform the experiment at the Department of Physics, Tripura University, India (23.50° N 91.25° E). The analysis of temporal data and dynamic spectrogram reveals distinct electromagnetic pulses in the frequency range of a few Hz to 2 kHz during the predicted time of peak activity of the shower. The spectral character of these pulses is found to be completely different from the spectral signatures originating from lightning discharges. During the peak activity period, the meteor counts using ELF method is found to be around 11,000 meteors hr−1, which is around 137 times more than the worldwide reported visible rate. The observational results are discussed from the viewpoint of deposition of meteoric dust particles and its interaction with ionospheric plasma, leading to emission of electromagnetic waves during the passage of meteors through the Earth’s atmosphere.