Astronomy Stories
Earth's Moon, public domain image
Pasadena, CA— “Can moons have moons?” This simple question—asked by the four-year old son of Carnegie’s Juna...
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Pasadena, CA— Miguel Roth, director of Carnegie’s Las Campanas Observatory in Chile from 1990 to 2014 and the current representative of the Giant Magellan Telescope Organization (GMTO) in...
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An artist’s conception of a type Ia supernova exploding, courtesy of ESO.
Pasadena, CA—New work from the Carnegie Supernova Project provides the best-yet calibrations for using type Ia supernovae to measure cosmic distances, which has implications for our...
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Pan-STARRS image showing the host galaxy of the newly discovered supernova ASASSN-18bt
Pasadena, CA—A supernova discovered by an international group of astronomers including Carnegie’s Tom Holoien and...
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Pasadena, CA—Carnegie’s Anthony Piro was part of a Caltech-led team of astronomers who observed the peculiar death of a massive...
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John Graham
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...
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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...
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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...
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The recent discovery that the universe is expanding at an accelerating rate has profoundly affected physics. If the universe were gravity-dominated then it should be decelerating. These contrary results suggest a new form of “dark energy”—some kind of repulsive force—is...
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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...
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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...
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Guillermo Blanc wants to understand the processes by which galaxies form and evolve over the course of the history of the universe. He studies local galaxies in the “present day” universe as well as very distant and therefore older galaxies to observe the early epochs of galaxy...
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With the proliferation of discoveries of planets orbiting other stars, the race is on to find habitable worlds akin to the Earth. At present, however, extrasolar planets less massive than Saturn cannot be reliably detected. Astrophysicist John Chambers models the dynamics of these newly found giant...
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Galacticus is not a super hero; it’s a super model used to determine the formation and evolution of the galaxies. Developed by Andrew Benson, the George Ellery Hale Distinguished Scholar in Theoretical Astrophysics, it is one of the most advanced models of galaxy formation available. Rather...
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In the days after the death of Stephen Hawking, some of our scientists reflected on meeting him, on his contributions to science and science communication, and his impact on humanity.  ALAN BOSS,...
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An unusual stellar explosion is shining new light on the origins of a specific subgroup of Type Ia supernovae. Called LSQ14fmg, the exploding star exhibits certain characteristics that are unlike any...
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Dwarf galaxies are enigmas wrapped in riddles. Although they are the smallest galaxies, they represent some of the biggest mysteries about our universe. While many dwarf galaxies surround our own...
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Alan Boss
January 14, 2022

Washington, DC— Carnegie’s Alan Boss was named one of 23 new Fellows of the American Astronomical Society. The honorees were chosen for their “extraordinary achievement and service” to the field.

Boss, whose contributions to the fields of astronomy and astrophysics are numerous, was specifically recognized for “innovative theoretical investigations of the formation of stars and exoplanets” as well as “tireless leadership within the exoplanet exploration community in ensuring that NASA executes a credible and successful exoplanet program.”

The AAS fellowship program began in 2020 and its members include professional astronomers

Mars mosaic courtesy of NASA.
January 13, 2022

Washington, DC—Organic molecules found in a meteorite that hurtled to Earth from Mars were synthesized during interactions between water and rocks that occurred on the Red Planet about 4 billion years ago, according to new analysis led by Carnegie’s Andrew Steele and published by Science.  

The meteorite, called Allan Hills (ALH) 84001, was discovered in the Antarctic in 1984 and is considered one of the oldest known projectiles to reach Earth from Mars.  

“Analyzing the origin of the meteorite’s minerals can serve as a window to reveal both the geochemical processes occurring early in Earth’s history and Mars’ potential for

Milky Way and stellar streams, Credit: James osephides and S5 Collaboration.
January 11, 2022

Pasadena CA—A new map of a dozen associations of moving stars—called stellar streams—orbiting within the Milky Way’s halo has brought astronomers one step closer to revealing the properties of the dark matter enveloping our galaxy and shaping the universe.  Accepted for publication in The Astrophysical Journal, the map was produced by an international collaboration of astronomers, including several current and former Carnegie scientists.

“Stellar streams are the shredded remains of neighboring small galaxies and star clusters that are torn apart by the Milky Way,” explained Carnegie’s Josh Simon, a co-author on the paper. “These

Artist conception. Credit: NASA GSFC/CIL/Adriana Manrique Gutierrez
December 23, 2021

Washington, DC—A a perfect seasonal gift to astronomers around the world—the James Webb Space Telescope successfully launched on the morning of December 25.  This next-generation space telescope will drive a new era of discovery—with capabilities that will complement the upcoming era of extremely large ground-based telescopes, including the Giant Magellan Telescope under construction at Carnegie’s Las Campanas Observatory in Chile.

Several Carnegie astronomers will be among the first to lead projects using data from JWST observations. Their planned investigations will span the breadth of expertise at our Observatories and Earth and Planets Laboratory

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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 Carnegie-Spitzer-IMACS (CSI) survey, currently underway at the Magellan-Baade 6.5m telescope in Chile, has been specifically designed to characterize normal galaxies and their environments at a distance of about 4 billion years post Big Bang, expresses by astronomers as  z=1.5.

The survey selection is done using the Spitzer Space Telescope Legacy fields, which provides as close a selection by stellar mass as possible.

Using the IMACS infrared camera, the survey goal is to study galaxies down to low light magnitudes. The goal is to reduce the variance in the density of massive galaxies at these distances and times to accurately trace the evolution of the galaxy mass

The recent discovery that the universe is expanding at an accelerating rate has profoundly affected physics. If the universe were gravity-dominated then it should be decelerating. These contrary results suggest a new form of “dark energy”—some kind of repulsive force—is driving the universe. To get a grasp of dark energy, it is extremely important that scientists get the most accurate measurements possible of Type Ia supernovae. These are specific types of exploring stars with exceptional luminosity that allow astronomers to determine distances and the acceleration rate at different distances. At the moment, the reality of the accelerating universe remains

The Carnegie Hubble program is an ongoing comprehensive effort that has a goal of determining the Hubble constant, the expansion rate of the universe,  to a systematic accuracy of 2%. As part of this program, astronomers are obtaining data at the 3.6 micron wavelength using the Infrared Array Camera (IRAC) on Spitzer Space Telescope. The team has demonstrated that the mid-infrared period-luminosity relation for Cepheids, variable stars used to determine distances and the rate of the expansion,  at 3.6 microns is the most accurate means of measuring Cepheid distances to date. At 3.6 microns, it is possible to minimize the known remaining systematic uncertainties in the Cepheid

Guillermo Blanc wants to understand the processes by which galaxies form and evolve over the course of the history of the universe. He studies local galaxies in the “present day” universe as well as very distant and therefore older galaxies to observe the early epochs of galaxy evolution. Blanc conducts a series of research projects on the properties of young and distant galaxies, the large-scale structure of the universe, the nature of Dark Energy—the mysterious repulsive force, the process of star formation at galactic scales, and the measurement of chemical abundances in galaxies.

To conduct this work, he takes a multi-wavelength approach including

Anthony Piro is the George Ellery Hale Distinguished Scholar in Theoretical Astrophysics at the Carnegie Observatories. He is a theoretical astrophysicist studying compact objects, astrophysical explosions, accretion flows, and stellar dynamics. His expertise is in nuclear physics, thermodynamics, condensed matter physics, General Relativity, and fluid and magneto-hydrodanmics. He uses this background  to predict new observational phenomena as well as to understand the key underlying physical mechanisms responsible for current observations. He uses a combination of analytic and simple numerical models to build physical intuition for complex phenomena.

Piro recieved his 

Alycia Weinberger wants to understand how planets form, so she observes young stars in our galaxy and their disks, from which planets are born. She also looks for and studies planetary systems.

Studying disks surrounding nearby stars help us determine the necessary conditions for planet formation. Young disks contain the raw materials for building planets and the ultimate architecture of planetary systems depends on how these raw materials are distributed, what the balance of different elements and ices is within the gas and dust, and how fast the disks dissipate.

Weinberger uses a variety of observational techniques and facilities, particularly ultra-high spatial-

Globular clusters are spherical systems of some 100,000  gravitationally bound stars. They are among the oldest components of our galaxy and are key to understanding the age and scale of the universe. Previous measurements of their distances have compared the characteristics of different types of stars in the solar neighborhood with the same types of stars found in the clusters. However, these measurements have systematic errors, which limit the determination of cluster ages and distances.

 Ian Thompson has a different approach to the problem: using observations of exceedingly rare Detached Eclipsing Binary stars. These systems have two separated stars orbiting each