On Sunday February 15, 2009 (11:00
A.M. CST), News 8 cameraman Eddie Garcia recorded a fireball 180 km
south of downtown Austin, Texas. From SE of Austin to Ft. Worth, many
people observed the bolide. Using National Weather Service Doppler
reflectivity radar measurements (NWS Ft. Worth and Granger stations) the
bolide location was recorded at 11:03 A.M. D. Dawn led a team, which
interviewed witnesses in the strewn field within 48 hours following the
fall. In southern Hill County, straddling the northern corner of
McLennan County, sonic booms were widely heard for a duration of 20–30 s
in the area from Hubbard to Aquilla. The fireball was bright and the
meteoroid fragmented overhead near Birome, where the sonic booms were
reported loudest. In Aquilla, the rumblings were likened to “a jet
taking off,” and the event was described at 30–40 degrees altitude in
the eastern sky, with some horizontal movement. Strong sonic booms were
widely reported from Hubbard and Penelope. J. Trussell heard a rumbling,
which initially vibrated a window at about 11:00 A.M. CST. He looked
north along Ash Creek and saw two segments of a smoke trail separated by
a thick cloud. Shortly afterwards, a blackened stone rolled near his
foot and a second impacted a shed behind him. Meteorites were found on
February 17 by D. Sadilenko and D. Dawn on the banks Ash Creek, northern
corner of McLennan County.
large masses were found: a 1.7 kg specimen recovered by L.B. Etter on a
farm in Menlow; a 1.673 kg stone purchased by meteorite dealer S.
Arnold; and a 1.5 kg specimen purchased by M. Farmer from an anonymous
landowner who suggested it was found in the vicinity of Aquilla. All
other masses reported were less than 300 g each. According to reports,
over 300 stones were found in McLennan and Hill Counties with an
estimated total of over 11.7 kg. Approximately 75% of the finds were
completely covered with thick black fusion crust, often with dark rust
colored spots, even on specimens recovered within two days of the fall.
Drizzle and heavy dew wet specimens in the strewn field for the first
two nights following the fall, and heavy rain on March 13 soaked the
area, oxidizing many specimens. Broken and cut surfaces reveal a
dark/light gray breccia.
(A. Rubin, UCLA):
Many plagioclase grains exceed 50 µm in size. Some metal grains contain
irregular troilite inclusions. Metallic Cu is present in some metal.
Metal- and sulfide-bearing shock veins are present and the meteorite
exhibits silicate darkening.
Rubin, UCLA): Olivine (Fa24.2 ± 0.2; n = 12),
low-Ca pyroxene (Fs20.5 ± 0.7, Wo1.6 ± 0.2; n =
12). Taenite is more abundant than kamacite; average compositions:
kamacite (Fe = 93.1%, Ni = 5.8%, Co = 0.83%; n = 4) and taenite (Fe =
69.6%, Ni = 30.3%, Co = 0.30%; n = 9).
|State/Prov/County:||McLennan County, TX|
|Date:||15-Feb- 2009, fell 1|
|Fayalite (mol%):||24.2 ±0.2|
|Ferrosilite (mol%):||20.5 ±0.7|
|Wollastonite (mol%):||1.6 ±0.2|
|Classifier:||A. Rubin, UCLA|
|Type spec mass (g):||30.6|
|Type spec location:||UCLA|