Leonard Kornos

Independent identification of meteor showers in EDMOND database

Abstract Cooperation and data sharing among national networks and International Meteor Organization Video Meteor Database (IMO VMDB) resulted in European viDeo MeteOr Network Database (EDMOND). The current version of the database (EDMOND 5.0) contains 144 749 orbits collected from 2001 to 2014. This paper presents the results obtained by a proposed new independent method of meteor showers identification, which is applied to the current version of the database (EDMOND 5.0). In the first step of the survey we used the DSH criterion to find groups around each meteor within the similarity threshold. Mean parameters of the groups were calculated and compared using a new function DX based on geocentric parameters ( λ ⊙ , α, δ, and Vg). Similar groups were merged into final clusters (representing meteor showers), and compared with the IAU Meteor Data Center list of meteor showers.

Near-Earth asteroid (3200) Phaethon: Characterization of its orbit, spin state, and thermophysical parameters

Context. The near-Earth asteroid (3200) Phaethon is an intriguing object: its perihelion is at only 0.14 au and is associated with the Geminid meteor stream. Aims. We aim to use all available disk-integrated optical data to derive a reliable convex shape model of Phaethon. By interpreting the available space- and ground-based thermal infrared data and Spitzer spectra using a thermophysical model, we also aim to further constrain its size, thermal inertia, and visible geometric albedo. Methods. We applied the convex inversion method to the new optical data obtained by six instruments and to previous observations. The convex shape model was then used as input for the thermophysical modeling. We also studied the long-term stability of Phaethon’s orbit and spin axis with a numerical orbital and rotation-state integrator. Results. We present a new convex shape model and rotational state of Phaethon: a sidereal rotation period of 3.603958(2) h and ecliptic coordinates of the preferred pole orientation of (319°, −39°) with a 5° uncertainty. Moreover, we derive its size ( D = 5.1 ± 0.2 km), thermal inertia (Γ = 600 ± 200 J m –2 s –1/2 K –1 ), geometric visible albedo ( p V = 0.122 ± 0.008), and estimate the macroscopic surface roughness. We also find that the Sun illumination at the perihelion passage during the past several thousand years is not connected to a specific area on the surface, which implies non-preferential heating.

Meteor showers of comet C/1917 F1 Mellish

December Monocerotids and November Orionids are weak but established annual meteor showers active throughout November and December. Analysis of a high quality orbits subset of the SonotaCo video meteor data base shows that the distribution of orbital elements, geocentric velocity and also the orbital evolution of the meteors and potential parent body may imply a common origin for these meteors coming from the parent comet C/1917 Fl Mellish. This is also confirmed by the physical properties and activity of these shower meteors. An assumed release of meteoroids at the perihelion of the comet in the past and the sky-plane radiant distribution reveal that the December Monocerotid stream might be younger than the November Orionids. A meteoroid transversal component of ejection velocity at the perihelion must be larger than 100 m s -1 . A few authors have also associated December Canis Minorids with the comet C/1917 F1 Mellish. However, we did not find any connection.

Photographic Leonids 1998 Observed at Modra Observatory

Results of photographic observations of the 1998 Leonids performed at Modra Observatory (Slovakia) are presented and discussed. During an exposure time of 7 hr 14 min on November 16/17 a total of 168 meteors were recorded. Photographic rates of bright Leonid meteors as well as their magnitude distribution are presented and compared with the results obtained by other techniques. The photographic 1998 Leonids exhibit a maximum at the solar longitude 234.52°, Equinox 2000.0 (Nov. 17, 01:40 UT).