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

Survey of cometary CO2, CO, and particulate emissions using the Spitzer Space Telescope: Smog check for comets

We surveyed 23 comets using the Infrared Array Camera on the Spitzer Space Telescope in wide filters centered at 3.6 and 4.5 microns. Emission in the 3.6 micron filter arises from sunlight scattered by dust grains; these images generally have a coma near the nucleus and a tail in the antisolar direction due to dust grains swept back by solar radiation pressure. The 4.5 micron filter contains the same dust grains, as well as strong emission lines from CO2 and CO gas; these show distinct morphologies, in which cases we infer they are dominated by gas. Based on the ratio of 4.5 to 3.6 micron brightness, we classify the survey comets as CO2+CO "rich" and "poor." This classification is correlated with previous classifications by A'Hearn based on carbon-chain molecule abundance, in the sense that comets classified as "depleted" in carbon-chain molecules are also "poor" in CO2+CO. The gas emission in the IRAC 4.5 micron images is characterized by a smooth morphology, typically a fan in the sunward hemisphere with a radial profile that varies approximately as the inverse of projected distance from the nucleus, as would apply for constant production and free expansion. There are very significant radial and azimuthal enhancements in many of the comets, and these are often distinct between the gas and dust, indicating that ejection of solid material may be driven either by H2O or CO2. Notable features in the images include the following. There is a prominent loop of gas emission from 103P/Hartley 2, possible due to an outburst of CO2 before the Spitzer image. Prominent, double jets are present in the image of 88P/Howell. A prominent single jet is evident for 3 comets. Spirals are apparent in 29P and C/2006 W3; we measure a rotation rate of 21 hr for the latter comet. Arcs (possibly parts of a spiral) are apparent in the images of 10P/Tempel 2, and 2P/Encke.Comment: accepted for publication in Icaru

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

Demonstration of gaps due to Jupiter in meteoroid streams. What happened with the 2003 Pi-Puppids ?

The original publication is available in Astronomy & Astrophysics at www.aanda.org.International audienceWe simulated the dynamics of the Pi-Puppid meteoroid stream. The evolution of such a short period stream is dominated by close encounters with Jupiter. The effect is so great that it can cause the stream to split into several parts and form gaps. The difference in period of each part leads to the possibility of a meteor outburst on Earth while the parent body is at aphelion. Past observations are linked to streams ejected in the 19th and 20th century. Sometimes there are overlaps between several streams ejected at different perihelion passages of the parent body, affecting the time of maximum meteor activity. Generally speaking, observations suffer from a lack of coverage. In the 1972 and 2003 cases, only radio observations are available, and they are not in accordance with our predictions. This can be due to the radio detectors' lack of sensivity or to the poor knowledge of the efficiency of this physical process

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&

Encounters of the dust trails of comet 45P/Honda-Mrkos-Pajdusakova with Venus in 2006

The original publication is available in Astronomy & Astrophysics at www.aanda.org.International audienceAims. We aim to investigate the dynamical fate of meteoroids ejected during past perihelion passages of comet 45P/Honda-Mrkos-Pajdusakova that intersect the orbit of Venus. Of particular interest is the possibility, borne of previous work, that a significant flux of these particles will reach the planet during early June and late August 2006, when the Venus Express spacecraft will be operating in orbit around Venus. Methods. We have simulated the generation of meteoroid trails ejected by the comet at some past perihelion passages, and numericaly integrated them forward in time until they approach Venus in 2006. Results. On the inbound leg of the comet's path towards perihelion, we find a trail composed of dust particles ejected between 1943 and 1980 that encounters Venus on 9 June 2006 at a distance of 0.009 AU. On the outbound leg, we observe a dense trail of particles ejected between 1985 and 2001 that measures 3.4 × 10−4 AU (5 × 104 km) in half-width, and passes under the planet at a distance of 1.72 × 10−3 AU (2.6 × 105 km) on 30 August. Based on these results, we conclude that, on both occasions, the incident flux at Venus will likely be too low to allow for the detection of a shower by optical means. We discuss the circumstances under which Venus Express may encounter a significant flux of small particles detectable through impact ionization or disturbances in the interplanetary magnetic field

Meteor hurricane at Mars on 2014 October 19 from comet C/2013 A1

International audienceComet C/2013 A1 will make a very close approach with the planet Mars on 2014 October 19. For this event, we compute the density of cometary dust particles around the Mars Express spacecraft, in order to assess the real risk for space probes. We also estimate the zenithal hourly rate (ZHR) and discuss observational opportunities for the resulting Martian meteor shower. We find, for a surface of 2.7 m 2 , that the Mars Express spacecraft will experience approximately 10 impacts from particles larger than 100 µm in size. The fluence per square metre is found to be 3.5 during the encounter. The equivalent ZHR is computed to be ZHR 4.75 × 10 9 h −1 , making this event the strongest meteor storm ever predicted. We call this event a 'meteor hurricane', which we define to be a meteor shower with ZHR exceeding 10 6 h −1

A new method to predict meteor showers. I. Description of the model

The original publication is available in Astronomy & Astrophysics at www.aanda.org.International audienceObservations of meteor showers allow us to constrain several cometary parameter and to retrieve useful parameters on cometary dust grains, for instance the dust size distribution index s. In this first paper, we describe a new model to compute the time and level of a meteor shower whose parent body is a known periodic comet. The aim of our work was to use all the available knowledge on cometary dust to avoid most of the "a priori" hypotheses of previous meteoroid stream models. The ejection velocity is based on a hydrodynamic model. Because of the large amount of particles released by the comet, it is impossible to compute the orbits of all of them. Instead, we link each computed particle with the real number of meteoroids ejected in the same conditions, through a "dirty snowball" cometary model calibrated with the [A f ρ] parameter. We used a massive numerical integration for all the particles without hypotheses about size distribution. The time of maximum is evaluated from the position of the nodes of impacting meteoroids. The model allows us to compute ephemerides of meteors showers and the spatial density of meteors streams, from which a ZHR can be estimated. At the end a fit of our predictions with observations allows us to compute the dust size distribution index. We used 2002 and 2003 leonid meteor showers to illustrate our method. The application of our model to the Leonid meteor shower from 1833 to 2100 is given in Paper II