Alan Boss is a theorist and an observational astronomer. His theoretical work focuses on the formation of binary and multiple stars, triggered collapse of the presolar cloud that eventually made  the Solar System, mixing and transport processes in protoplanetary disks, and the formation of gas giant and ice giant protoplanets. His observational works centers on the Carnegie Astrometric Planet Search project, which has been underway for the last decade at Carnegie's Las Campanas Observatory in Chile.

While fragmentation is universally recognized as the dominant formation mechanism for binary and multiple stars, there are still major questions. The most important of these is the role of magnetic fields. Boss has been studying the collapse of individual molecular cloud cores via special computer modeling, to understand the chances for binary and multiple star system formation and to define which cloud cores are likely to collapse to form single stars, such as our Sun.

 A shock from an exploding star called a supernova has been considered the most attractive mechanism for introducing short-lived radioisotopes (SLRIs) into the solar nebula. Boss has been modeling the problem of simultaneous triggering and injection. His results support the supernova trigger hypothesis because thin supernova shocks are better at injecting SLRIs than the thick planetary nebula. Boss is currently running 3D models, including the effects of target cloud rotation, to learn to what extent injection occurs into a protoplanetary disk formed as a result of triggered collapse.

Boss also studies the mixing and transport of solids in protoplanetary disks to form gas giant planets similar to Jupiter, or to undergo outbursts in marginally gravitationally unstable (MGU) disks. Boss' 3D models show how crystalline silicates, observed in the outskirts of protoplanetary disks and in long-period comets, could have been formed by thermal “cooking” closer to their protostar and then transported back outward to cooler regions of the disk. Boss has joined with Conel Alexander and Morris Podolak to study the detailed thermal evolution of finite-size particles in MGU disks.

 While the core accretion mechanism is still considered by most to be the leading explanation for the formation of our solar system's gas giant planets, for the last decade Boss has been working to learn whether another mechanism, disk instability, could also form gas giant planets.

 Along with Alycia Weinberger and Ian Thompson, 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 six years of CAPSCam data, they are beginning to see likely true astrometric wobbles..

 Boss received his B.S. from the University of South Florida and his M.A. and Ph. D. in physics from UC-Santa Barbara, where he was also a postdoctoral researcher. Before joining Carnegie in 1981 as a staff associate (now a staff scientist), he was a research associate at NASA Ames Research Center. For more information see http://www.dtm.ciw.edu/people/alan-p-boss

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Caltech logo
March 17, 2020

The Carnegie Institution for Science is consolidating our California research departments into an expanded presence in Pasadena. With this move, we are building on our existing relationship with Caltech, with a goal of broadening our historic collaborations in astronomy and astrophysics and pursuing new opportunities in ecology and plant biology that will support the global fight against climate change.

This plan, which affects our research operations in Pasadena and Palo Alto, reflects Carnegie’s ongoing efforts to extend our leadership in space, Earth, and life sciences and to enhance our ability to explore new frontiers.

In selecting our Pasadena location, we

 Illustration of DS Tuc AB by M. Weiss, CfA.
March 9, 2020

Pasadena, CA— A new kind of astronomical observation helped reveal the possible evolutionary history of a baby Neptune-like exoplanet.

To study a very young planet called DS Tuc Ab, a Harvard & Smithsonian Center for Astrophysics-led team that included six Carnegie astronomers—Johanna Teske, Sharon Wang, Stephen Shectman, Paul Butler, Jeff Crane, and Ian Thompson—developed a new observational modeling tool. Their work will be published in The Astrophysical Journal Letters and represents the first time the orbital tilt of a planet younger than 45 million years—or about 1/100th the age of the Solar System—has been measured.

“A

John Mulchaey
March 2, 2020

Pasadena, CA—John Mulchaey, Director and Crawford H. Greenewalt Chair of the Carnegie Observatories, was presented with a Humanitarian STAR Award by the honor’s founding body—the Rotary Club of Sierra Madre. These recognitions, which reward “outstanding scientific and technological achievements with significant humanitarian benefit” were launched locally in 2015, but now include chapters and recipients from around the country.

Mulchaey was selected for the club’s Helios award in acknowledgment of his longstanding efforts at promoting outreach events and activities to share astronomy with enthusiasts of all ages throughout the Los Angeles area.

February 26, 2020

Washington, DC— Carnegie astronomers Stephen Shectman and Alycia Weinberger were selected for the inaugural class of Fellows of the American Astronomical Society in recognition of their “extraordinary achievement and service” to the field. 

The newly established accolade will honor members of the organization for original research, innovative technique and instrumentation development, significant public outreach and educational efforts, and other noteworthy contributions to the society. To launch the program, the AAS selected 200 “legacy” fellows, including Shectman and Weinberger. Carnegie trustee Sandra Faber of UC Santa Cruz and former-

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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/

Evolutionary geneticist Moises Exposito-Alonso joined the Department of Plant Biology as a staff associate in September 2019. He investigates whether and how plants will evolve to keep pace with climate change by conducting large-scale ecological and genome sequencing experiments. He also develops computational methods to derive fundamental principles of evolution, such as how fast natural populations acquire new mutations and how past climates shaped continental-scale biodiversity patterns. His goal is to use these first principles and computational approaches to forecast evolutionary outcomes of populations under climate change to anticipate potential future

Staff Associate Kamena Kostova joined the Department of Embryology in November 2018. She studies ribosomes, the factory-like structures inside cells that produce proteins. Scientists have known about ribosome structure, function, and biogenesis for some time. But, a major unanswered question is how cells monitor the integrity of the ribosome itself. Problems with ribosomes have been associated with diseases including neurodegeneration and cancer. The Kostova lab investigates the fundamental question of how cells respond when their ribosomes break down using mass spectrometry, functional genomics methods, and CRISPR genome editing.

Kostova received a B.S. in Biology from the

Sally June Tracy applies cutting-edge experimental and analytical techniques to understand the fundamental physical behavior of materials at extreme conditions. She uses dynamic compression techniques with high-flux X-ray sources to probe the structural changes and phase transitions in materials at conditions that mimic impacts and the interiors of terrestrial and exoplanets. She is also an expert in nuclear resonant scattering and synchrotron X-ray diffraction. She uses these techniques to understand novel behavior at the electronic level.  Tracy received her Ph.D. from the California Institute of

The Ludington lab investigates complex ecological dynamics from microbial community interactions using the fruit fly  Drosophila melanogaster. The fruit fly gut carries numerous microbial species, which can be cultured in the lab. The goal is to understand the gut ecology and how it relates to host health, among other questions, by taking advantage of the fast time-scale and ease of studying the fruit fly in controlled experiments.