178 research outputs found
Minor Planet 2008 ED69 and the Kappa Cygnid Meteor Shower
Until recently, the kappa Cygnids (IAU#12) were considered an old shower, because the meteors were significantly dispersed in node, radiant, and speed, despite being 28-38° inclined. In 1993, an outburst of kappa Cygnids was observed, which implied that this meteoroid stream was relatively young, instead. At least some dust was still concentrated in dust trailets. Until now, no active comet parent body was known, however, and the wide 22° dispersion of nodes was difficult to explain. This work reports that a minor planet has been discovered that has the right orbital dynamics to account for the kappa Cygnids. Minor planet 2008 ED69 is intrinsically bright, with H = 16.7 ± 0.3, and moves in a highly inclined orbit (i = 36.3°). With one node near Jupiter's orbit, the perihelion distance, longitude of perihelion, and node quickly change over time, but in a manner that keeps dust concentrated for a long period of time. The stream is more massive than the remaining body, and a form of fragmentation is implicated. A break-up, leaving a stream of meteoroids and at least the one remaining fragment 2008 ED69, can account for the observed dispersion of the kappa Cygnids in Earth's orbit, if the formation epoch is about 2-3 nutation cycles ago, dating to around 4000-1600 BC. Most of that debris now passes close to the orbit of Venus, making the kappa Cygnids a significant shower on Venus
3D/Biela and the Andromedids: Fragmenting versus Sublimating Comets
Comet 3D/Biela broke up in 1842/1843 and continued to disintegrate in the returns of 1846 and 1852. When meteor storms were observed in November of 1872 and 1885, it was surmised that those showers were the debris from that breakup. This could have come from one of two sources: (1) the initial separation of fragments near aphelion or (2) the continued disintegration of the fragments afterward. Alternatively, the meteoroids could simply have come from water vapor drag when the fragments approached perihelion (option 3). We investigated the source of the Andromedid storms by calculating the dynamical evolution of dust ejected in a normal manner by water vapor drag in the returns from 1703 to 1866, assuming that the comet would have remained similarly active over each return. In addition, we simulated the isotropic ejection of dust during the initial fragmentation event at aphelion in December of 1842. We conclude that option 2 is the most likely source of meteoroids encountered during the 1872 and 1885 storms, but this accounts for only a relatively small amount of mass lost in a typical comet breakup
Real-Time Flux Density Measurements of the 2011 Draconid Meteor Outburst
During the 2011 outburst of the Draconid meteor shower, members of the Video Meteor Network of the International Meteor Organization provided, for the first time, fully automated flux density measurements in the optical domain. The data set revealed a primary maximum at 20:09 UT ± 5 min on 8 October 2011 (195.036° solar longitude) with an equivalent meteoroid flux density of (118 ± 10) × 10/km/h at a meteor limiting magnitude of +6.5, which is thought to be caused by the 1900 dust trail. We also find that the outburst had a full width at half maximum of 80 min, a mean radiant position of α = 262.2°, δ = +56.2° (±1.3°) and geocentric velocity of v = 17.4 km/s (±0.5 km/s). Finally, our data set appears to be consistent with a small sub-maximum at 19:34 UT ±7 min (195.036° solar longitude) which has earlier been reported by radio observations and may be attributed to the 1907 dust trail. We plan to implement automated real-time flux density measurements for all known meteor showers on a regular basis soon.Peer reviewedFinal Accepted Versio
Hyperbolic meteors: is CNEOS 2014-01-08 interstellar?
In 2019 a claim was made that the CNEOS 2014-01-08 meteor is interstellar.
However, apparent interstellar meteors have been detected for decades.
Moreover, they are expected from any meteor observation survey, as a natural
consequence of measurement error propagation. Here we examine if enough
scientific data were published to identify the orbital and physical nature of
CNEOS 2014-01-08. Given the lack of proof regarding the accuracy of the
observation, the derivation of the trajectory, velocity and tensile strength,
and given the current state of meteor observations and reduction tools, we find
no scientific ground to conclude about the interstellar orbit nor the physical
properties of CNEOS 2014-01-08. Moreover, given the current data release of
this object, to find any piece at the bottom of the ocean seems extremely
unlikely.Comment: 4 pages, 0 figure, published in WGN, the Journal of the IM
Spectral properties of the largest asteroids associated with Taurid Complex
We obtained spectra of six of the largest asteroids (2201, 4183, 4486, 5143,
6063, and 269690) associated with Taurid complex. The observations were made
with the IRTF telescope equipped with the spectro-imager SpeX. Their taxonomic
classification is made using Bus-DeMeo taxonomy. The asteroid spectra are
compared with the meteorite spectra from the Relab database. Mineralogical
models were applied to determine their surface composition. All the spectral
analysis is made in the context of the already published physical data.
Five of the objects studied in this paper present spectral characteristics
similar to the S taxonomic complex. The spectra of ordinary chondrites
(spanning H, L, and LL subtypes) are the best matches for these asteroid
spectra. {\bf The asteroid} (269690) 1996 RG3 presents a flat featureless
spectrum which could be associated to a primitive C-type object. The increased
reflectance above 2.1 microns constrains its geometrical albedo to a value
around 0.03.
While there is an important dynamical grouping among the Taurid Complex
asteroids, the spectral data of the largest objects do not support a common
cometary origin. Furthermore, there are significant variations between the
spectra acquired until now.Comment: Accepted for publication in A&
Numerical Modeling of Cometary Meteoroid Streams Encountering Mars and Venus
We have simulated numerically the existence of meteoroid streams that encounter the orbits of Mars and Venus, potentially producing meteor showers at those planets. We find that 17 known comets can produce such showers, the intensity of which can be determined through observations. Six of these streams contain dense dust trails capable of producing meteor outbursts
Evidence for a meteoritic origin of the September 15, 2007, Carancas crater
On September 15th, 2007, around 11:45 local time in Peru, near the Bolivian border, the
atmospheric entry of a meteoroid produced bright lights in the sky and intense detonations. Soon after,
a crater was discovered south of Lake Titicaca. These events have been detected by the Bolivian
seismic network and two infrasound arrays operating for the Comprehensive Nuclear-Test-Ban Treaty
Organization, situated at about 80 and 1620 km from the crater. The localization and origin time
computed with the seismic records are consistent with the reported impact. The entry elevation and
azimuthal angles of the trajectory are estimated from the observed signal time sequences and backazimuths.
From the crater diameter and the airwave amplitudes, the kinetic energy, mass and
explosive energy are calculated. Using the estimated velocity of the meteoroid and similarity criteria
between orbital elements, an association with possible parent asteroids is attempted. The favorable
setting of this event provides a unique opportunity to evaluate physical and kinematic parameters of
the object that generated the first actual terrestrial meteorite impact seismically recorded
French Meteor Network for High Precision Orbits of Meteoroids
There is a lack of precise meteoroids orbit from video observations as most of the meteor stations use off-the-shelf CCD cameras. Few meteoroids orbit with precise semi-major axis are available using film photographic method. Precise orbits are necessary to compute the dust flux in the Earth s vicinity, and to estimate the ejection time of the meteoroids accurately by comparing them with the theoretical evolution model. We investigate the use of large CCD sensors to observe multi-station meteors and to compute precise orbit of these meteoroids. An ideal spatial and temporal resolution to get an accuracy to those similar of photographic plates are discussed. Various problems faced due to the use of large CCD, such as increasing the spatial and the temporal resolution at the same time and computational problems in finding the meteor position are illustrated
Monitoring Observations of the Jupiter-Family Comet 17P/Holmes during 2014 Perihelion Passage
We performed a monitoring observation of a Jupiter-Family comet, 17P/Holmes,
during its 2014 perihelion passage to investigate its secular change in
activity. The comet has drawn the attention of astronomers since its historic
outburst in 2007, and this occasion was its first perihelion passage since
then. We analyzed the obtained data using aperture photometry package and
derived the Afrho parameter, a proxy for the dust production rate. We found
that Afrho showed asymmetric properties with respect to the perihelion passage:
it increased moderately from 100 cm at the heliocentric distance r_h=2.6-3.1 AU
to a maximal value of 185 cm at r_h = 2.2 AU (near the perihelion) during the
inbound orbit, while dropping rapidly to 35 cm at r_h = 3.2 AU during the
outbound orbit. We applied a model for characterizing dust production rates as
a function of r_h and found that the fractional active area of the cometary
nucleus had dropped from 20%-40% in 2008-2011 (around the aphelion) to
0.1%-0.3% in 2014-2015 (around the perihelion). This result suggests that a
dust mantle would have developed rapidly in only one orbital revolution around
the sun. Although a minor eruption was observed on UT 2015 January 26 at r_h =
3.0 AU, the areas excavated by the 2007 outburst would be covered with a layer
of dust (<~ 10 cm depth) which would be enough to insulate the subsurface ice
and to keep the nucleus in a state of low activity.Comment: 25 pages, 6 figures, 2 tables, ApJ accepted on December 29, 201
A 2022 -Herculid meteor cluster from an airborne experiment: automated detection, characterization, and consequences for meteoroids
Context. The existence of meteor clusters has long since been a subject of
speculation and so far only seven events have been reported, among which two
involve less than five meteors, and three were seen during the Leonid storms.
Aims. The 1995 outburst of Comet 73P/Schwassmann-Wachmann was predicted to
result in a meteor shower in May 2022. We detected the shower, proved this to
be the result of this outburst, and detected another meteor cluster during the
same observation mission. Methods. The {\tau}-Herculids meteor shower outburst
on 31 May 2022 was continuously monitored for 4 hours during an airborne
campaign. The video data were analyzed using a recently developed
computer-vision processing chain for meteor real-time detection. Results. We
report and characterize the detection of a meteor cluster involving 38
fragments, detected at 06:48 UT for a total duration of 11.3 s. The derived
cumulative size frequency distribution index is relatively shallow: s = 3.1.
Our open-source computer-vision processing chain (named FMDT) detects 100% of
the meteors that a human eye is able to detect in the video. Classical
automated motion detection assuming a static camera was not suitable for the
stabilized camera setup because of residual motion. Conclusions. From all
reported meteor clusters, we crudely estimate their occurrence to be less than
one per million observed meteors. Low heliocentric distance enhances the
probability of such meteoroid self-disruption in the interplanetary space.Comment: 6 pqges, 5 figure
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