We are all made of stardust. Almost all of the chemical elements were produced by nuclear reactions in the interiors of stars. When a star dies a fraction of the elements is released into the inter-stellar gas clouds, out of which successive generations of stars form.

 Astronomers have a basic understanding of this chemical enrichment cycle, but chemical evolution and nulceosynthesis are still not fully understood. Andrew McWilliam measures the detailed chemical composition of Red Giant stars, which are about as old as the galaxy and retain their original chemical composition.  He is seeking answer to questions such as: What are the sites of nucleosynthesis? What modulates element production? What can we learn about galactic history by reading this fossil record?

McWilliam tests nucleosynthesis and chemical evolution theory by studying the composition of Red Giant stars in different systems. The central bulge of our galaxy, for instance, probably evolved quickly and was the destination for infalling gas. Dwarf galaxies likely evolved slowly and lost much of their initial gas. McWilliam and colleagues verified theory by studying these different systems; although the two systems displayed more complexity than anticipated.

  Approximately 100 million supernova events—giant stellar explosions—have occurred in our galaxy. The ejecta were mixed and averaged, resulting in an homogeneous composition. This homogeneity makes it very difficult to determine the range of element ratios produced by supernovae. McWilliam and colleagues studied the composition of a sample of very old stars, with few elements (dubbed metal-poor) and found that they possess an enormous range in certain element abundance ratios indicating that not all supernovae are alike. Their results indicate that certain elements in the extreme metal-poor stars were dominated by the ejecta from very few supernovae, in some cases from just one. These very rare stars are ideal for testing supernova nucleosynthesis predictions, and to probe the early evolution of the galaxy.

McWilliam received his B.Sc. from London University and his M.A. and Ph.D. from the University of Texas–Austin. Before joining the Carnegie staff as staff astronomer he was a research associate at Cerro Tololo Inter American Observatory, a visiting assistant professor at New Mexico State University, a Carnegie postdoctoral associate and the first Barbara McClintock Fellow at Carnegie. For more information see http://obs.carnegiescience.edu/users/andy

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The Magellan Telescopes at Carnegie's Las Campanas Observatory in Chile
September 6, 2022

Washington, DC— An anonymous bequest of $34.8 million will enable Carnegie to continue to play a leading role advancing the frontiers of astronomy and astrophysics. The largest gift to the Institution since it was founded by Andrew Carnegie, this new fund will support staff and instrumentation at the Carnegie Observatories.

“Since George Ellery Hale built the first telescope on Mount Wilson, Carnegie has played a forefront role in some of the most important astronomical discoveries of the modern era,” said Carnegie President Eric D. Isaacs. “This transformative gift will empower new generations of Carnegie astronomers to reveal the physics that underpins

Artist's concept of the Giant Magellan Telescope courtesy of GMTO
August 2, 2022
Washington, DC—A Carnegie-led effort secured $205 million toward the completion of the next-generation Giant Magellan Telescope, which is currently being built at our Las Campanas Observatory in Chile. When completed, the GMT will enable breakthrough astronomy—from revealing the fundamental physics underpinning the cosmos to advancing our ability to search for life on distant worlds.

Last November, the National Academies of Science, Engineering, and Medicine ranked the GMT as a top strategic priority, recommending an injection of federal support to complete its construction and bring about a new era in astronomy. The endorsement was part of the academies’ review of the

Artist's conception of JWST. Credit: NASA GSFC/CIL/Adriana Manrique Gutierrez
July 24, 2022

Pasadena, CA— The first of six projects led by Carnegie-affiliated astronomers will, for the next three days, use the James Webb Space Telescope to make some of the most-accurate measurements ever taken of the chemistry of very early galaxies—studying light that traveled 10 billion years to reach us.

Carnegie’s Gwen Rudie and Allison Strom, formerly a Carnegie-Princeton Postdoctoral Fellow, now a Northwestern professor, are heading up the CECILIA project, which will take extremely accurate measurements from a carefully selected set of ancient galaxies in order to understand their compositions and chart the remarkable growth that they experienced in the universe

June 28, 2022

Washington, DC—The violent event that likely preceded our Solar System’s formation holds the solution to a longstanding meteorite mystery, says new work from Carnegie’s Alan Boss published in The Astrophysical Journal.

The raw material from which our Solar System was constructed was dispersed when the shock wave from an exploding supernova injected material into a cloud of dust and gas, causing it to collapse in on itself. In the aftermath of this event, most of the injected matter was gravitationally drawn into the center of the whirlwind, where the intense buildup of pressure enabled nuclear fusion to commence, and the Sun was born. The young star was

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The fund supports a postdoctoral fellowship in astronomy that rotates between the Carnegie Science departments of Terrestrial Magnetism in Washington, D.C., and the Observatories in Pasadena California. 

The Earthbound Planet Search Program has discovered hundreds of planets orbiting nearby stars using telescopes at Lick Observatory, Keck Observatory, the Anglo-Australian Observatory, Carnegie's Las Campanas Observatory, and the ESO Paranal Observatory.  Our multi-national team has been collecting data for 30 years, using the Precision Doppler technique.  Highlights of this program include the detection of five of the first six exoplanets, the first eccentric planet, the first multiple planet system, the first sub-Saturn mass planet, the first sub-Neptune mass planet, the first terrestrial mass planet, and the first transit planet.Over the course of 30 years we have

The Giant Magellan Telescope will be one member of the next class of super giant earth-based telescopes that promises to revolutionize our view and understanding of the universe. It will be constructed in the Las Campanas Observatory in Chile. Commissioning of the telescope is scheduled to begin in 2021.

The GMT has a unique design that offers several advantages. It is a segmented mirror telescope that employs seven of today’s largest stiff monolith mirrors as segments. Six off-axis 8.4 meter or 27-foot segments surround a central on-axis segment, forming a single optical surface 24.5 meters, or 80 feet, in diameter with a total collecting area of 368 square meters. The GMT

Along with Alycia Weinberger and Ian Thompson, Alan Boss has been running the Carnegie Astrometric Planet Search (CAPS) program, which searches for extrasolar planets by the astrometric method, where the planet's presence is detected indirectly through the wobble of the host star around the center of mass of the system. With over eight years of CAPSCam data, they are beginning to see likely true astrometric wobbles beginning to appear. The CAPSCam planet search effort is on the verge of yielding a harvest of astrometrically discovered planets, as well as accurate parallactic distances to many young stars and M dwarfs. For more see  http://instrumentation.obs.carnegiescience.edu/

Ana Bonaca is Staff Member at Carnegie Observatories. Her specialty is stellar dynamics and her research aims to uncover the structure and evolution of our galaxy, the Milky Way, especially the dark matter halo that surrounds it. In her research, she uses space- and ground-based telescopes to measure the motions of stars, and constructs numerical experiments to discover how dark matter affected them.

She arrived in September 2021 from Harvard University where she held a prestigious Institute for Theory and Computation Fellowship. 

Bonaca studies how the uneven pull of our galaxy’s gravity affects objects called globular clusters—spheres made up of a million

Peter Gao's research interests include planetary atmospheres; exoplanet characterization; planet formation and evolution; atmosphere-surface-interior interactions; astrobiology; habitability; biosignatures; numerical modeling.

His arrival in September 2021 continued Carnegie's longstanding tradition excellence in exoplanet discovery and research, which is crucial as the field prepares for an onslaught of new data about exoplanetary atmospheres when the next generation of telescopes come online.

Gao has been a part of several exploratory teams that investigated sulfuric acid clouds on Venus, methane on Mars, and the atmospheric hazes of Pluto. He also

Anne Pommier's research is dedicated to understanding how terrestrial planets work, especially the role of silicate and metallic melts in planetary interiors, from the scale of volcanic magma reservoirs to core-scale and planetary-scale processes.

She joined Carnegie in July 2021 from U.C. San Diego’s Scripps Institution of Oceanography, where she investigated the evolution and structure of planetary interiors, including our own Earth and its Moon, as well as Mars, Mercury, and the moon Ganymede.

Pommier’s experimental petrology and mineral physics work are an excellent addition to Carnegie’s longstanding leadership in lab-based mimicry of the

Johanna Teske became the first new staff member to join Carnegie’s newly named Earth and Planets Laboratory (EPL) in Washington, D.C., on September 1, 2020. She has been a NASA Hubble Fellow at the Carnegie Observatories in Pasadena, CA, since 2018. From 2014 to 2017 she was the Carnegie Origins Postdoctoral Fellow—a joint position between Carnegie’s Department of Terrestrial Magnetism (now part of EPL) and the Carnegie Observatories.

Teske is interested in the diversity in exoplanet compositions and the origins of that diversity. She uses observations to estimate exoplanet interior and atmospheric compositions, and the chemical environments of their formation