Aguas Zargas
A commission received in August from Curator Sally Lai was to respond to the aesthetic qualities, the narratives, scientific value and astronomical background of meteorites in the collection of Graham Ensor. I chose the ‘Aguas Zargas’ for my response. 5 other artists were commissioned and can be seen in the link ‘The Meteorite Collection’ below:
Aguas Zargas: a very recent fall.
History: At 21:07 local time on 23 April 2019, a meteorite fall was reported in Aguas Zarcas, San Carlos county, Alajuela province, Costa Rica. The fireball traveled WNW to ESE and was caught on cameras of the National Seismological Network (RSN) at the summit of Poás and Turrialba volcanoes, and from the Volcanological and Seismological Observatory of Costa Rica (OVSICORI). Sightings were reported from Quepos (Central Pacific) in the south and north to La Palmera in San Carlos. The first piece recovered, 1152g, crashed through a house at 10°23’29.03″N, 84°20’28.58″W. A dog house was hit by a 280g piece at 10°24’9.35″N 84°21’51.26″W. The BRAMON (Brazilian Meteors Observation Network), UNESP (São Paulo State University) and USP (University of São Paulo) teams determined the atmospheric trajectory of the bolide from four security videos and dashcam cameras. The bolide had an entry angle of 73° relative to the ground, traveling 20.7 km in the 4-s analyzed interval, with an atmospheric velocity of 14 km/s. Analysis shows a projected elliptical strewn-field with major axis length of 6.3 and minor axis of 3.3 km. Hundreds of stones were recovered within the projected strewn-field. The bolide orbit was determined, with the following preliminary elements: semi-major axis 2.7 AU, eccentricity 0.63, inclination 3.09°, pericenter longitude of 185.3° and ascending node 33.4°. Current total recovered mass is around 27 kg, of which ~11 kg was collected before rain fell over the fall site.
Physical characteristics: (L. Garvie, ASU) Hundreds of fusion-crusted stones ranging from 0.1 to 1868g. Stones under ~50 g are typically angular to blocky and lack regmaglypts. Also found were several plate-like, oriented stones. For example, one oriented plate is 13 cm wide and 1 cm thick. Many stones are oriented with a domed leading edge and well-developed roll-over lip along the rim of the trailing edge. Larger stones, especially those near 1 kg, show broad regmaglypts, some well developed. The fusion crust on several of the trailing edge surfaces is iridescent. Pre-rain material crushed in a few ml of water emits a powerful “Murchison-like” odor, though with a more prominent compost-like scent.
It has been almost exactly 50 years since the last important one of the same type fell, a CM carbonaceous meteorite called Murchison in Australia. This is about the most studied meteorite ever because of its primitive nature full of amino acids formed in space. It is the kind that probably brought the building blocks of life to earth and perhaps much of our water. Aguas Zarcas thus is very exciting material. The sample in Graham’s collection is just over 130g. You can still smell the volatiles and amino acids from space from this sample. Carbonaceous meteorites are analysed to determine the date of the solar system which works out at around 4.7 thousand million years…so these are the oldest materials we can handle. More recently there are studies that show they contain material from before the solar system formed, possibly from a supernova that initiated the spinning dust ring and formation of our solar system.