Pluie de météorites

[Olivier Girard]

Un peu de science-fiction : http://www.cidehom.com/apod.php?_date=120707 future solution pour nous protéger des méchants géocroiseurs ?

[Dom...]

Ah ben finalement, elle serait plus grosse que ce qui a été dit au début : 17 m, pour 7 à 10000 tonnes.
Et une explosion de 500 kilotonnes de TNT (30 fois Hiroshima) à 15/20 km du sol.

Bigre.

Ah, et puis, il parait que c'est un OVNI qui a fait péter la météorite !!! Impayable la Presse Galactique !!!

[Eric Chariot]

Oui ça commence à délirer ferme

[Vincent Boudon]

Vous avez tout faux ! C'était en fait le Nyan Cat !



:lol :lol :lol

[Vincent Boudon]

Plus sérieusement, voici des données précises de l'UAI, transmises sur la liste FRIPON :

Electronic Telegram No. 3423
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
CBAT Director: Daniel W. E. Green; Hoffman Lab 209; Harvard University;
20 Oxford St.; Cambridge, MA 02138; U.S.A.
e-mail: cbatiau@eps.harvard.edu (alternate cbat@iau.org)
URL http://www.cbat.eps.harvard.edu/index.html" onclick="window.open(this.href);return false;
Prepared using the Tamkin Foundation Computer Network

TRAJECTORY AND ORBIT OF THE CHELYABINSK SUPERBOLIDE
Jiri Borovicka, Pavel Spurny, and Lukas Shrbeny, Astronomical Institute
of the Academy of Sciences, Ondrejov, Czech Republic, report that they have
computed the atmospheric trajectory and velocity of the superbolide of 2013
Feb. 15.139 UT (3h20m UT), which caused some damage in the city of
Chelyabinsk, Russia. They used seven casual video records provisionally
calibrated with Google Maps tools. The trajectory was assumed to be linear.
The geographical coordinates of selected points along the trajectory are as
tabulated below:

Relative Longitude Latitude Height Velocity Notes
Time (s) (deg E) (deg N) (km) (km/s)

0.00 64.266 54.508 91.83 17.5 beginning of
registration
9.18 61.913 54.788 41.02 17.5 minor flare
11.20 61.455 54.836 31.73 17.5 major flare
12.36 61.159 54.867 25.81 17.5 flare
13.20 60.920 54.891 21.05 12.5 minor flare
16.20 60.606 54.922 14.94 4.3 end of
registration

The observed trajectory was 254 km long. The azimuth of the trajectory was
279.5 degrees, and the slope was 16.5 degrees to the horizontal (for the end
point). The uncertainty of the radiant is about one degree. The uncertainty
of the position of the trajectory is about 1 km (at the beginning, up to 4
km).
The pre-entry object that caused the superbolide was relatively fragile.
Severe fragmentation started at a height of 32 km under dynamic pressure of 4
MPa. The mass of the largest fragment, which landed in the lake Chebarkul,
was estimated to be 200-500 kg. One or two meteorites of the mass of several
tens of kg can be expected not far from the village Travniki. One piece of
mass approximately 1 kg may have landed to the northwest of Shchapino.
Numerous small fragments can be expected in the wide band located about 5 km
south of the trajectory, mostly between longitudes 60.9 and 61.35 degrees.
The blast wave, which strongly affected Chelyabinsk, was generated
between heights of 25 and 30 km. The radiant and heliocentric orbit were
calculated to be as follows:

Apparent radiant: Right ascension 328.6 +/- 1.0 deg
(equinox 2000.0) Declination +8.0 +/- 1.0 deg
Velocity 17.5 +/- 0.5 km/s

Geocentric radiant: Right ascension 334.7 +/- 1.2 deg
Declination -1.0 +/- 1.4 deg
Velocity 13.2 +/- 0.7 km/s

Orbit: a = 1.55 +/- 0.07 AU e = 0.50 +/- 0.02
q = 0.768 +/- 0.011 AU Q = 2.33 +/- 0.14 AU
(equinox 2000.0) Peri. = 109.7 +/- 1.8 deg Node = 326.41 deg
i = 3.6 +/- 0.7 deg

The data do not allow determination of the initial mass of the object prior
to entering the atmosphere. The trajectory will be further refined in the
future, provided that proper in situ calibrations of the videos are made.


NOTE: These 'Central Bureau Electronic Telegrams' are sometimes
superseded by text appearing later in the printed IAU Circulars.

(C) Copyright 2013 CBAT
2013 February 23 (CBET 3423) Daniel W. E. Green

[Vincent Boudon]

Et une sacrée image dans l'APPD :
[thumb]http://apod.nasa.gov/apod/image/1302/Ah ... G_7083.jpg[/thumb]

http://apod.nasa.gov/apod/ap130223.html" onclick="window.open(this.href);return false;

[Eric Chariot]

Excellentes ces infos ! On n'aurait pas une image de l'ellipse d'impact ?

[Eric Chariot]

Il y a déjà une page wiki en anglais sur la météorite de Chebarkoul, celle qui est tombée dans le lac. On a pas encore retrouvé celle de 200 kg qui a creusé le cratère, mais on a retrouvé quelques fragments sur la glace du lac.
http://en.wikipedia.org/wiki/Chebarkul_meteorite" onclick="window.open(this.href);return false;

[Vincent Boudon]

53 petits fragments tout de même autour de ce trou ...
[thumb]http://upload.wikimedia.org/wikipedia/c ... ke_ice.jpg[/thumb]

Une chondrite standard, semble-t-il.

[Eric Chariot]

Un reportage rigolo où on voit des enfants chercher des météorites dans la neige. Et la mafia russe de la météorite qui s'organise

Visiblement y en a plein de ces petits cailloux, mais encore une fois, ce ne sont pas eux qui ont causé les dégâts, ceux là ont du tomber à faible vitesse.

http://www.nytimes.com/2013/02/19/world ... ments.html" onclick="window.open(this.href);return false;