Parent Comet Research Articles

Near-Earth Asteroids as the parents of the $\delta$-Cancrid Meteoroid Stream

Abstract The $\delta$-Cancrid meteoroid stream forms four active meteor showers which are observable on the Earth annually during January-February and August-September. The stream's definite parent comet has not been established. We performed a search for near-Earth
 asteroids (NEAs) associated with this stream. We have followed the backward evolution of the orbital elements of a sample of NEAs and found their orbits at the Earth-crossing positions. Using these orbits, we calculated the theoretical parameters of meteor showers
 associated with the considered NEAs. We carried out our search for observable active showers that match theoretically predicted ones with published data, and the result turned out that the predicted meteor showers of 13 NEAs were identified with the active showers produced by the $\delta$-Cancrid meteoroid stream. The comet-like orbits of NEAs and established association with active meteor showers indicate their common cometary origin. The NEAs considered are moving within the stream and likely represent the dormant remnants of a parent comet of the $\delta$-Cancrid asteroid-meteoroid complex disintegrated more than 12 thousand years
 ago.

Determining the population of large meteoroids in major meteor showers

We have estimated the largest meteoroids present in major meteor showers from observations conducted between 2019-2022 by the Geostationary Lightning Mapper (GLM) instrument on the GOES-R satellites. Our integrated time area products for the Leonids, Perseids and eta Aquariids are of order 5 × 1010 km2 hours. We compute photometric masses for shower fireballs using the approach of Vojáček et al. (2022) to correct from narrow-band GLM luminosity to bolometric luminosity and apply the luminous efficiency relation of Ceplecha & McCrosky (1976) at high speeds. Between 2019 and 2022, the showers definitely observed by GLM were the Leonids, Perseids, and eta Aquariids, with probable detections of the Orionids and Taurids. We find the largest meteoroids to be of order 7 kg for the Leonids, 3 kg for the Perseids, and 3 kg for the eta Aquariids, corresponding to meteoroids of ≈0.2 m diameter. The Orionids and Taurids had maximum meteoroid masses of 4 kg and 150 kg respectively. The Leonids and eta Aquariids are well fit by a single power-law with differential mass exponent, s, of 2.08 ± 0.08 and 2.00 ± 0.09 over the mass range 10−7< m < 1 kg. All showers had maximum meteoroid masses compatible with Whipple gas-drag ejection, with the exception of the Perseids which have much larger meteoroids than expected a result also consistent with observations from ground based instruments. This may reflect preferential ejection in narrow jets or possibly some form of mantle erosion/release in the past for the parent comet, 109P/Swift-Tuttle.

Near-Earth asteroids of cometary origin associated with the Virginid complex

The Virginid meteoroid streams produce a series of meteor showers active annually during February–May. A certain parent comet is not found but a related association of some showers with near-Earth asteroids was previously established and a cometary origin of these asteroids was suggested. We performed a new search for NEAs belonging to the Virginid asteroid–meteoroid complex. On the base of calculation of orbital evolution of a sample of NEAs and determination of theoretical features of related showers a search for observable active showers close to theoretically predicted ones was carried out. As a result, the predicted showers of 27 NEAs were identified with the showers of the Virginid complex. Revealed association points to a cometary nature of NEAs that are moving within the stream and may be considered as extinct fragments of a larger comet-progenitor of the Virginid asteroid–meteoroid complex.

The Lyrids meteor shower: A historical perspective

The April Lyrid meteor shower is the oldest meteor shower ever recorded continuously throughout history, dating as far back as 687 BC. Before the 20th century, historical sources only provided reports of two years of strong activity and up to nine possible additional events. Currently, the shower has low activity, but it has had significant episodes that, during the 20th century, seem to repeat at time intervals that are multiples of 12yr or 60 yr. Earlier outbursts may have also occurred with a frequency consistent with this period. Outbursts of activity are also known in other meteor showers. The classical explanation that they are correlated to the close proximity of the parent comet to the Earth was proven wrong in the last years of the 20th century and this is also clear in the case of the April Lyrids, whose parent comet is C/1861 G1 (Thatcher), with an orbital period of about 400 yr. Our previous research has led us to compile an additional list of possible April Lyrids in the last 2000 years. This paper has two objectives. First, to present the list of possible Lyrids that we have compiled that would significantly increase the number of historical observations considered to date. Secondly, to study if the historical data fit well with the main theories and recent studies concerning the Lyrids.

Prediction of the collisions of meteoroids originating in comet 21P/Giacobini-Zinner with the Mercury, Venus, and Mars

After the prediction of meteor showers in the Earth’s atmosphere caused by the particles originating in the nucleus of comet 21P/Giacobini-Zinner, we went on with the prediction of showers on the other three terrestrial planets. Based on our modeling of theoretical stream of the parent comet, we predicted several related impacted meteoroid (on Mercury) or meteor (on Venus and Mars) showers. There occurred the filaments, in the stream, with the particles coming to each planet from a similar direction. We found that this is a consequence of the specific distribution of argument of perihelion (peaked close to the value of 180°) and longitude of ascending node of the stream, and that the particles collide with each planet in an arc of their orbits being close to perihelion.

The grain size distribution of matrix in primitive chondrites

AbstractThe matrix of primitive chondrites is composed of submicron crystals embedded in amorphous silicates. These grains are thought to be the remains of relatively unprocessed dust from the inner regions of the protoplanetary disk. The matrix of primitive meteorites is often compared to chondritic porous interplanetary dust particles (CP‐IDPs) which are believed to be of cometary origin, having accreted in the outermost regions of the solar nebula. Crystalline grains in CP‐IDPs show evidence of a size–density relationship between the silicates and sulfides suggesting that these components experienced sorting prior to accretion. Here, we investigate whether such evidence of sorting is also present in the matrix constituents of primitive chondrites. We report findings from our study of grain size distributions of discrete silicate and opaque (sulfide and metal) grains within the matrix of the primitive meteorites Acfer 094 (C2‐ung.), ALHA77307 (CO3), MIL 07687 (C3‐ung.), and QUE 99177 (CR2). Mean radii of matrix silicate grains range from 103 nm in QUE 99177 to 2018 nm in MIL 07687. The opaque grains show a wider variation, with average radii ranging from 15 nm in QUE 99177 to 219 nm in MIL07687. Our results indicate that, in contrast to CP‐IDPs, the size distribution of matrix components of these primitive meteorites cannot be explained by aerodynamic sorting that took place prior to accretion. We conclude that any evidence of sorting is likely to have been lost due to a greater variety and degree of processing experienced on these primitive chondrites than on cometary parent bodies.

Long-period dynamical evolution of the meteoroid stream originating in comet 21P/Giacobini-Zinner

We investigated the dynamical evolution of the meteoroid stream originating in the nucleus of comet 21P/Giacobini-Zinner. We created 20 partial models, in each assuming 10,000 test particles, and fixed values for the evolutionary time and the strength of the Poynting–Robertson effect. These models provided a “mosaic” with which to map the entire stream. We confirmed that the orbit of the parent comet and the orbits of the test particles, representing the meteoroids, evolved rapidly. This fast evolution resulted in a relatively short duration (up to approx. 1000 years) of the orbital concentrations of the meteoroids that could be identified as the meteor showers. We confirmed the relationship between comet 21P and the October Draconid meteor shower, #9. In addition to this shower, we predicted another five showers related to the comet. Four of these showers were also identified with their real counterparts. Some identifications were multiple. Specifically, we further found an association, or indication of association of 21P, with the ι-Cygnids, #525, August β-Aquariids, #474, June ξ1-Sagittariids, #861, ξ2-Capricornids, #623, Northern σ-Sagittariids, #167, α-Capricornids, #1, Daytime Capricornids-Sagittariids, #115, and ν-Draconids, #220.

New and improved orbits of historical comets: Late 4th and 5th century

Since as early as the 19th century, many scholars have devoted themselves to the calculation of sets of orbital elements for particular historical comets. In many cases, these studies have led to proposing orbits that have given satisfactory answers to contemporary observations or later reports about these celestial bodies. As new records or improved translations of existing sources appear, the already calculated orbits can be refined, or even new ones can be achieved. In this paper we focus on historical observations from Eastern and European countries in the late 4th and 5th centuries to suggest new determinations of orbital elements for some of these comets, or, where appropriate, to discuss or improve existing ones. We will also carry out a separate study of comets from the years AD422–423 and AD467, which have been suggested as the parent comets of the Kreutz system of sungrazer comets.

Evolution of the dust trail of comet 17P/Holmes

ABSTRACT The massive outburst of the comet 17P/Holmes in 2007 October is the largest known outburst by a comet thus far. We present a new comprehensive model describing the evolution of the dust trail produced in this phenomenon. The model comprises of multiparticle Monte Carlo simulation including the solar radiation pressure effects, gravitational disturbance caused by Venus, Earth and Moon, Mars, Jupiter and Saturn, and gravitational interaction of the dust particles with the parent comet itself. Good accuracy of computations is achieved by its implementation in Orekit, which executes Dormad-Prince numerical integration methods with higher precision. We demonstrate performance of the model by simulating particle populations with sizes from 0.001 to 1 mm with corresponding spherically symmetric ejection speed distribution, and towards the Sun outburst modelling. The model is supplemented with and validated against the observations of the dust trail in common nodes for 0.5 and 1 revolutions. In all cases, the predicted trail position showed a good match to the observations. Additionally, the hourglass pattern of the trail was observed for the first time within this work. By using variations of the outburst model in our simulations, we determine that the assumption of the spherical symmetry of the ejected particles leads to the scenario compatible with the observed hourglass pattern. Using these data, we make predictions for the two-revolution dust trail behaviour near the outburst point that should be detectable by using ground-based telescopes in 2022.

Recent formation and likely cometary activity of near-Earth asteroid pair 2019 PR2–2019 QR6

ABSTRACT Asteroid pairs are genetically related asteroids that recently separated (&amp;lt;few million years), but still reside on similar heliocentric orbits. A few hundred of these systems have been identified, primarily in the asteroid main belt. Here, we studied a newly discovered pair of near-Earth objects (NEOs): 2019 PR2 and 2019 QR6. Based on broad-band photometry, we found these asteroids to be spectrally similar to D-types, a type rare amongst NEOs. We recovered astrometric observations for both asteroids from the Catalina Sky Survey from 2005, which significantly improved their fitted orbits. With these refinements we ran backwards orbital integrations to study formation and evolutionary history. We found that neither a pure gravitational model nor a model with the Yarkovsky effect could explain their current orbits. We thus implemented two models of comet-like non-gravitational forces based on water or CO sublimation. The first model assumed quasi-continuous, comet-like activity after separation, which suggested a formation time of the asteroid pair $300^{+120}_{-70}$ yr ago. The second model assumed short-term activity for up to one heliocentric orbit (∼13.9 yr) after separation, which suggested that the pair formed 272 ± 7 yr ago. Image stacks showed no activity for 2019 PR2 during its last perihelion passage. These results strongly argue for a common origin that makes these objects the youngest asteroid pair known to date. Questions remain regarding whether these objects derived from a parent comet or asteroid, and how activity may have evolved since their separation.

On the origin of the Kreutz family of sungrazing comets

ABSTRACT We evaluate numerically three different models for the parent comet of the Kreutz family of sungrazers: (i) A Centaur on a highly inclined or retrograde orbit that diffuse to the inner planetary region where it became a sungrazer (Model 1). (ii) A parent comet injected from the Oort cloud straight into a near-parabolic, sungrazing orbit. Near perihelion the comet was disrupted by tidal forces from the Sun giving rise to a myriad of fragments that created the Kreutz family (Model 2). (iii) A two-step process by which an Oort cloud comet is first injected in a non-sungrazing, Earth-crossing orbit where its semimajor axis decreases from typical Oort cloud values (a ∼ 104 au) to around 102 au, and then it evolves to a sungrazing orbit by the Lidov–Kozai mechanism (Model 3). Model 1 fails to produce sungrazers of the Kreutz type. Model 2 produces some Kreutz sungrazers and has the appeal of being the most straightforward. Yet the impulses received by the fragments originated in the catastrophic disruption of the parent comet will tend to acquire a wide range of orbital energies or periods (from short-period to long-period orbits) that is in contradiction with the observations. Model 3 seems to be the most promising one since it leads to the generation of some sungrazers of the Kreutz type and, particularly, it reproduces the clustering of the argument of perihelion ω of the observed Kreutz family members around 60°–90°, as a natural consequence of the action of the Lidov–Kozai mechanism.

About C/539W1 and C/1245D1 as the parent comet of 15-BOOTIDS

In a recent paper published in this journal it was presented an interesting study on the 2019 outburst of the 15-Bootids and it was suggested the possibility that comet C/539W1 was the parent comet of this meteor shower. It was also deducted from the method employed that this parent comet could have had a first passage through perihelion around the year AD1260. In this paper, we review both assumptions and we propose the possibility that the previous perihelion passage of the parent comet of the 15-Bootids was observed and recorded as C/1245D1.

Modeling the meteoroid streams of comet C/1861 G1 (Thatcher), Lyrids

The meteoroid stream of long-period comet C/1861 G1 (Thatcher) is modeled in course to reveal the details of its structure. Specifically, we modeled several parts of the comet's theoretical stream, which were characterized by various values of evolutionary times and various strengths of the Poynting-Robertson effect. The dynamical behaviour of 10 ​000 test particles in each model from the time of their ejection up to the present was followed via a numerical integration of their orbits. The characteristics of the particles that moved on orbits approaching the Earth's orbit were used to predict a shower. Primarily, we wanted to find whether C/1861 G1 is the parent body of other meteor showers than the April Lyrids. However, we confirm that the orbit of this parent and its meteoroid stream is relatively stable during a long time and the meteoroids can collide with our planet only in the pre-perihelion orbital arc corresponding to the April Lyrids, No. 6, code LYR. Our modeling did not show any clustering of the meteoroids in the stream due to the gravitational perturbations that could explain the observed outbursts. The observed semi-major axes are, in general, smaller than those of the modeled particles and the parent comet because of a selection effect. Namely, the meteoroids in orbits with smaller semi-major axes pass the Earth's orbit more frequently. They are then observed and recorded in the data more often than the meteors with the larger axes.

Modeling the meteoroid streams of comets C/1894 G1 (Gale) and C/1936 O1 (Kaho-Kozik-Lis)

We modeled meteoroid streams of two long-period comets, C/1894 G1 (Gale) and C/1936 O1 (Kaho-Kozik-Lis), in order to reveal their possible associations with meteor showers observed in the Earth’s atmosphere. For both comets, we modeled several parts of their theoretical streams, characterized by various values of evolutionary times and various strengths of the Poynting-Robertson effect. We studied the dynamical behaviour of 10000 test particles in each model from the time of their ejection up to the present. The characteristics of the particles that moved on orbits approaching the Earth’s orbit were used to predict showers which are related to the parent comet. We also mapped the impacts of possibly different cometary orbits on our predictions by creating models of the streams based on several cloned orbits.The modeling of the stream of the comet C/1894 G1 led to a prediction of a single shower related to the comet. Its existence was, however, not confirmed by real meteor data. Nevertheless, as a byproduct of our investigation, we found a new meteor shower in three databases of video meteors. In line with our suggestion, the shower was named the December ι-Ursae Majorids, No. 1049 and code DIU. We do not consider it as related to the comet.The stream models of the C/1936 O1 also yielded a single predicted shower. Its identification was, in this case, successful and also supported by the cloned-orbit models. In two datasets, we found a shower with characteristics consistent with the predictions. After our suggestion, the shower was newly added into the IAU MDC list as the January ψ-Scorpiids, No. 1048, code JAS.

The relationship between comet C/1853 G1 (Schweizer) and the γ-Aquilids and 52 Herculids meteor showers

ABSTRACT We modelled several discrete parts of the meteoroid stream originating in comet C/1853 G1 (Schweizer). In a given model, the orbit of this parent comet was integrated in time backwards for a chosen period (10 000, 20 000, 40 000, or 80 000 yr) and, then, a cloud of 10 000 test particles was assumed to be ejected from the nucleus at the moment of the nearest comet’s perihelion passage. This set was subsequently integrated forward, up to the present. The showers related to the comet were predicted on the basis of the dynamical properties of the particles moving in orbits that approached close to the orbit of the Earth at the present. An uncertainty of the comet’s nominal orbit and its possible consequences on the predicted showers was estimated with a simultaneous following of a set of cloned orbits. We confirmed the proposed relationship between the comet and the γ-Aquilids, #531. Furthermore, our study yielded an indication that comet C/1853 G1 could also be the parent body of another shower, 52 Herculids, #605. We also found the real shower corresponding to the γ-Aquilids in three video data bases used. The 52 Herculids were identified in one of these data bases.

Forbidden mass ranges for shower meteoroids

Burns et al. (1979) use the parameter β to describe the ratio of radiation pressure to gravity experienced by a small particle in the solar system. The central potential that these particles experience is effectively reduced by a factor of (1 − β), lowering the escape velocity. Burns et al. (1979) also provide a simple expression for the value of β at which particles ejected from a comet follow parabolic orbits and thus leave the solar system; this paper expands on this to calculate critical β values that take ejection velocity into account. We first derive an expression for the speed at which particles are ejected from a comet that is valid at all particle sizes. We then calculate β values for both idealized and real materials to determine which particles will be lost from meteor streams. We perform these calculations for cometary ejecta leading, trailing, and following the parent comet's nucleus for 10 major meteor showers. These values bound mass regimes within which meteoroids are ejected from the solar system and therefore cannot contribute to meteor showers.

The χ-Andromedids and January α-Ursae Majorids: A new and a probable shower associated with Comet C/1992 W1 (Ohshita)

The meteoroid stream of the long-period comet C/1992 W1 (Ohshita) is studied in course to predict and, eventually, confirm the existence of meteor showers originating in this comet. In total, we created 36 models, each representing a part of a theoretical meteoroid stream of the parent comet considered. We used a method of modeling which has given reliable results for the stream associated with other parent bodies in several past studies. We predict six meteor showers which originate from the nucleus of comet C/1992 W1. One of the predicted showers was identified with the χ-Andromedids, #580 in the IAU MDC list of all showers. The mean characteristics of another predicted shower are similar to the mean characteristics of the January α-Ursae Majorids, #606, given in the IAU MDC list. Evidence of both showers were also found in the three video databases which we considered; a shower resembling the χ-Andromedids was, moreover, found in the photographic data.

An outburst of delta Pavonids and the orbit of parent comet C/1907 G1 (Grigg-Mellish)

The CAMS New Zealand meteor shower survey detected a brief outburst of delta Pavonids (IAU shower 120, code DPA) with a compact radiant on March 31, 2019. This is the first instrumental detection of a shower long suspected to exist by visual observers monitoring the theoretical radiant of parent comet C/1907 G1 (Grigg-Mellish), despite it being listed in comet catalogs only with a parabolic orbit. The 2019 detection of an associated meteor shower confirms that this comet moves in an elliptical orbit. The range of allowed orbit solutions fitted to the 1907 observations of the comet strongly correlate node and semi-major axis. Taking into account the difference in node between comet orbit and dust trail, the time of the outburst constrains the comet orbital period to 447 ​± ​80 years (heliocentric), having last been near the sun in A. D. 1460 ​± ​80 years. The corresponding elliptical orbital elements for C/1907 G1 are presented. The short 23-min duration of the outburst (FWHM ​= ​16 ​min) confirms that C/1907 G1 is a small comet, having ejected dust with low ejection speeds. It passed close enough to Earth orbit to be a potentially hazardous comet in future returns.

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.

A photochemical model of ultraviolet atomic line emissions in the inner coma of comet 67P/Churyumov-Gerasimenko

Alice ultraviolet spectrometer onboard Rosetta space mission observed several spectroscopic emissions emanated from volatile species of comet 67P/Churyumov-Gerasimenko (hearafter 67P/C-G) during its entire escorting phase. The measured emission intensities, when the comet was at around 3 AU pre-perihelion, have been used to derive electron densities in the cometary coma assuming that H I and O I lines are solely produced by electron impact dissociative excitation of cometary parent species (Feldman et al., 2015). We have developed a photochemical model for comet 67P/C-G to study the atomic hydrogen (H I 1216, 1025, & 973 Å), oxygen (O I 1152, 1304, & 1356 Å), and carbon (C I 1561 & 1657 Å) line emissions by accounting for major production pathways. The developed model has been used to calculate the emission intensities of these lines as a function of nucleocentric projected distance and also along the nadir view by varying the input parameters, viz., neutral abundances and cross sections. We have quantified the percentage contributions of photon and electron impact dissociative excitation processes to the total intensity of the emission lines, which has an important relevance for the analysis of Alice observed spectra. It is found that in comet 67P/C-G, with a neutral gas production rate of about 1027 s−1 when it was at 1.56 AU from the Sun, photodissociative excitation processes are more significant compared to electron impact reactions in determining the atomic emission intensities. Based on our model calculations, we suggest that the observed atomic hydrogen, oxygen, and carbon emission intensities can be used to derive H2O, O2, and CO, abundances, respectively, rather than electron density in the coma of 67P/C-G, when the comet has a gas production rate of 1027 s−1 or more.