Young_lab


Researchers Karen Ziegler and Eric Tonui	CAI in the Allende meteorite	Keck telescope (E. Young)	Overview - artwork courtesy of NASA

Overview

Our projects range from the origins of the solar system to identifying isotopic biosignatures here on Earth. Our tools are mass spectrometers, ultraviolet and infrared lasers, ion exchange resins, telescopic observations of young stars, and presses for squeezing and heating rocks to emense pressures and temperatures. The latter involve collaborations with colleagues both here at UCLA and in other institutions. With these many tools we are conducting research spanning topics as diverse as the origins of the heat that melted rock in the early solar system to the meaning of isotope anomalies in Earth's atmosphere.

What are isotope geochemistry and cosmochemistry?

Isotope geochemistry is the application of isotopes of different elements as tracers of physicochemical processes in planetary systems, including the geospheres, hydrospheres, cryospheres and atmospheres of Earth, other planets, and asteroids and comets. Cosmochemistry refers to the study of meteorites. Isotope selectivity between materials such as minerals, liquids, and gases is related to the effects of mass on frequencies of vibrations at the atomic scale. We exploit this dependence of frequency on mass in our research. Below the relationship between frequency of vibrations of atoms and isotope substitution is dramatized with two "isotopologues" of the CO molecule (thanks Edwin Schauble):


C¹⁸O	C¹⁶O

	Isotope ratios of elements like O, Mg, Si, Cl, Fe, Pb, and Hf in meteorites and terrestrial samples are measured using gas-source mass spectrometers and a multiple-collector inductively coupled plasma-source mass spectrometer (MC-ICPMS) in the Young lab. At left is a view of the MC-ICPMS and ArF excimer laser ablation systems in our icp lab.
	We use vacuum extraction lines like the one shown here to extract oxygen from rocks in order to measure their oxygen isotope ratios. The process involves fluorinating samples with F₂ gas. Sampling methods include infrared laser heating, ultraviolet laser ablation, and acid digestion. Our primary analytical goal is to obtain high precision and high spatial resolution.

Linking astrophysics, meteoritics, and isotope chemistry

The question of the origins of rock in the solar system is central to our understanding of whether or not formation of rocky planets is "typical." If our solar system was formed by canonical processes in the Galaxy, then the chances that there are other planetary systems like ours is enhanced. Conversely, if the processes that gave rise to rocky planets are unconventional, the odds of finding other Earths are comparatively low. One of our goals is to compare what we learn about the early solar system through studies of meteorites to astronomical observations of stars in their infancy in order to address this question.

	Young stars have circumstellar disks of gas and dust that obscure the light emanating from them. This material is the progenitor of planets. At left is a disk of gas and dust around a star seen edge on. The disk is the dark horizontal band obscuring the reflected stellar light above and below the edge of the disk . The image also shows jets of material being ejected along the rotation axis of the star perpendicular to the disk. This is clear evidence for the dynamic nature of disk-star systems in their infancy, and underscore their complexity. We are interested in how these disks process materials to form planets.
	The image at left is a diagramatic representation of our solar system when it was on the order of one million years or younger. It is analogous to the young star and surrounding disk shown in the preceeding image. The diagram makes reference to various components of primitive meteorites (e.g., CAIs, or calcium aluminum-rich inclusions, like the one shown at the top of this page, and chondrules). The collimated bipolar jets seen in the above image of a star-disk system are depicted here as well. The young solar system was clearly a dynamical system with large variations in conditions from place to place.
	This image of the near-Earth asteroid (25143) Itokawa from the Hyabusa space craft, obtained by the Japan Aerospace Exploration Agency (JAXA), is an example of the sort of primitive body available to us for study in the solar system. We obtain samples of rocks like this in the form of meteorites. Cosmochemists try to relate the chemical and isotopic compositions of meteorites to the astronomical processes attending star and disk formation - processes like those shown in the preceeding images.
	The photograph at left shows the reflections of Ed Young (UCLA, on the right) and geochemist Hiroshi Ohmoto (Penn State, on the left) in one of the 36 pentagon-shaped segments that together comprise one of the two Keck telescope hyperbolic mirrors. Our group, in collaboration with our astronomy colleagues, is using the Keck NIRSPEC instrument, as well as other instruments on other telescopes, to test hypotheses for the cause of the oxygen isotope "anomaly" in the solar system. The oxygen isotope anomaly is a pronounced yet mysterious feature of the solar system. Our work represents a synergy between astronomers and cosmochemists that is forging a new brand of space science at UCLA.

Young Laboratory

Introduction

Overview