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

Explore Carnegie Science

SDSS/Caltech/Keck
October 11, 2018

Pasadena, CA—Carnegie’s Anthony Piro was part of a Caltech-led team of astronomers who observed the peculiar death of a massive star that exploded in a surprisingly faint and rapidly fading supernova, possibly creating a compact neutron star binary system. Piro’s theoretical work provided crucial context for the discovery. Their findings are published by Science.

Observations made by the Caltech team—including lead author Kishalay De and project principal investigator Mansi Kasliwal (herself a former-Carnegie postdoc)—suggest that the dying star had an unseen companion, which gravitationally siphoned away most of the star's mass before it exploded as a supernova. The explosion is

John Graham
September 24, 2018

Washington, DC—Carnegie astronomer John Graham—who also served during different periods as both Vice President and Secretary of the American Astronomical Society—died at home in Washington, D.C., September 13 after a battle with brain cancer. He was 79.

Graham, who specialized in the observation of young stars and the star formation process in the Milky Way and neighboring galaxies, joined Carnegie’s Department of Terrestrial Magnetism from the Cerro Tololo Inter-American Observatory in 1985. George Preston, who was Director of the Carnegie Observatories at the time Graham came to DTM, also offered Graham a simultaneous five-year adjunct appointment at the Mount Wilson and Las

August 9, 2018

Washington, D.C.—Observatories NASA Hubble Postdoctoral Fellow Maria Drout will receive the tenth Postdoctoral Innovation and Excellence Award (PIE). These awards are made through nominations from the departments and are chosen by the Office of the President. The recipients are awarded a cash prize for their exceptionally creative approaches to science, strong mentoring, and contributing to the sense of campus community.

Maria Drout was one of four Carnegie astronomers who, along with colleagues from UC Santa Cruz, provided the first-ever glimpse of two neutron stars colliding last August. She was first author on a Science paper, which measured the changing light from that merger

August 2, 2018

Pasadena, CA—What happens when a star behaves like it exploded, but it’s still there?

About 170 years ago, astronomers witnessed a major outburst by Eta Carinae, the brightest known star in our Milky Way galaxy. The blast unleashed almost as much energy as a standard supernova explosion.

Yet, Eta Carinae survived.

An explanation for the eruption has eluded astrophysicists, but Carnegie telescopes played an important role in solving the mystery.

Researchers can’t t a time machine back to the mid-1800s to observe the outburst with modern technology. However, astronomers can use nature’s own “time machine,” courtesy of the fact that light travels at a finite

No content in this section.

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 improved the

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 will

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/ccd/caps.

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. 

Nick Konidaris is a staff scientist at the Carnegie Observatories and Instrument Lead for the SDSS-V Local Volume Mapper (LVM). He works on a broad range of new optical instrumentation projects in astronomy and remote sensing. Nick's projects range from experimental to large workhorse facilities. On the experimental side, he recently began working on a new development platform for the 40-inch Swope telescope at Carnegie's Las Campanas Observatory that will be used to explore and understand the explosive universe.

 Nick and his colleagues at the Department of Global Ecology are leveraging the work on Swope to develop a new airborne spectrograph that will be used to provide a direct

Experimental petrologist Michael Walter became director of the Geophysical Laboratory beginning April 1, 2018. His recent research has focused on the period early in Earth’s history, shortly after the planet accreted from the cloud of gas and dust surrounding our young Sun, when the mantle and the core first separated into distinct layers. Current topics of investigation also include the structure and properties of various compounds under the extreme pressures and temperatures found deep inside the planet, and information about the pressure, temperature, and chemical conditions of the mantle that can be gleaned from mineral impurities preserved inside diamonds.

Walter had been at

Guoyin Shen's research interests lie in the quest to establish and to examine models for explaining and controlling the behavior of materials under extreme conditions. His research activities include investigation of phase transformations and melting lines in molecular solids, oxides and metals; polyamorphism in liquids and amorphous materials; new states of matter and their emergent properties under extreme conditions; and the development of enabling high-pressure synchrotron techniques for advancing compression science. 

He obtained a Ph.D. in mineral physics from Uppsala University, Sweden in 1994 and a B.S. in geochemistry from Zhejiang University, China in 1982. For more