(meteorobs) Hypervelocity meteors

[Francisco Ocaña]

Hello list,

before reading this article I thought that meteors at v>73km/s were 
uncommon. What do you know/think about this topic?


arXiv:0712.1571
Date: Mon, 10 Dec 2007 19:11:42 GMT   (401kb)

Title: Detection of an intergalactic meteor particle with the 6-m telescope
Authors: V.L. Afanasiev (1), V.V. Kalenichenko (2), I.D. Karachentsev 
(1) ((1)
  Special Astrophysical Observatory Russian Academy of Sciences (2)
  Astronomical Observatory, Kyiv Taras Shevchenko University)
Categories: astro-ph
Comments: 9 pages, 6 EPS figures
Journal-ref: Astrophysical Bulletin, 2007, v. 62, p. 301-310
\\
  On July 28, 2006 the 6-m telescope of the Special Astrophysical 
Observatory
of the Russian Academy of Sciences recorded the spectrum of a faint 
meteor. We
confidently identify the lines of FeI and MgI, OI, NI and 
molecular-nitrogen
N_2 bands. The entry velocity of the meteor body into the Earth's 
atmosphere
estimated from radial velocity is equal to 300 km/s. The body was 
several tens
of a millimeter in size, like chondrules in carbon chondrites. The 
radiant of
the meteor trajectory coincides with the sky position of the apex of the 
motion
of the Solar system toward the centroid of the Local Group of galaxies.
Observations of faint sporadic meteors with FAVOR TV CCD camera 
confirmed the
radiant at a higher than 96% confidence level. We conclude that this meteor
particle is likely to be of extragalactic origin. The following important
questions remain open: (1) How metal-rich dust particles came to be in the
extragalactic space? (2) Why are the sizes of extragalactic particles 
larger by
two orders of magnitude (and their masses greater by six orders of 
magnitude)
than common interstellar dust grains in our Galaxy? (3) If extragalactic 
dust
surrounds galaxies in the form of dust (or gas-and-dust) aureoles, can such
formations now be observed using other observational techniques (IR
observations aboard Spitzer satellite, etc.)? (4) If inhomogeneous
extragalactic dust medium with the parameters mentioned above actually 
exists,
does it show up in the form of irregularities on the cosmic microwave
background (WMAP etc.)?
\\ ( http://arxiv.org/abs/0712.1571 ,  401kb)