It is the time of the year again when planetary scientists come together in Houston to discuss their latest findings from meteorites to impact craters, from remote sensing to rover missions. It is the Lunar and Planetary Science Conference held in Houston, Texas.
I have been in my favourite session this morning, presolar grains. This session is normally concluding LPSC on a Friday afternoon so it was a big change for everyone, who is working on stardust, to meet first thing on a Monday morning.
The talks covered a wide range from spallation-produced Lithium, used to determine the age of these presolar grains to Barium and Strontium isotopes used to constrain the neutron production rates in stellar models to atom probe techniques dissecting nano-diamonds atom by atom. Ages coming out from the Lithium isotope measurements span a wide range from a few tens to thousands of millions of years and the latter are rather problematic as grains are not thought to survive this long in the interstellar medium. The Barium and Strontium isotope results suggest smaller neutron-production rates from 22Ne compared to current models as otherwise the measured results can’t be reproduced. The atom probe results show 13C-enriched nano-diamonds but there seem to be some unknown instrument effects skewing the results towards 13C-enrichment so more work will need to be done to ensure results are accurate.
But, the talk with the biggest discussion was definitely the last one in the session and it wasn’t actually about presolar grains, rather GEMS, glass with embedded metals and sulphides. These GEMS are very odd and hard to explain and there are two parties confronting each other, one claiming low-temperature irradiation and the second a hot environment where these particles are produced. A controversial but not escalating debate ended pretty much in a draw suggesting much more research needs to be done to get down to the source of the GEMS and who knows maybe both are right or none…..